Provided by: python-mpi4py-doc_3.1.6-9ubuntu1_all 
NAME
mpi4py - MPI for Python
Author Lisandro Dalcin
Contact
dalcinl@gmail.com
Date September 05, 2024
Abstract
This document describes the MPI for Python package. MPI for Python provides Python
bindings for the Message Passing Interface (MPI) standard, allowing Python applications to
exploit multiple processors on workstations, clusters and supercomputers.
This package builds on the MPI specification and provides an object oriented interface
resembling the MPI-2 C++ bindings. It supports point-to-point (sends, receives) and
collective (broadcasts, scatters, gathers) communication of any picklable Python object,
as well as efficient communication of Python objects exposing the Python buffer interface
(e.g. NumPy arrays and builtin bytes/array/memoryview objects).
INTRODUCTION
Over the last years, high performance computing has become an affordable resource to many
more researchers in the scientific community than ever before. The conjunction of quality
open source software and commodity hardware strongly influenced the now widespread
popularity of Beowulf class clusters and cluster of workstations.
Among many parallel computational models, message-passing has proven to be an effective
one. This paradigm is specially suited for (but not limited to) distributed memory
architectures and is used in today’s most demanding scientific and engineering application
related to modeling, simulation, design, and signal processing. However, portable
message-passing parallel programming used to be a nightmare in the past because of the
many incompatible options developers were faced to. Fortunately, this situation
definitely changed after the MPI Forum released its standard specification.
High performance computing is traditionally associated with software development using
compiled languages. However, in typical applications programs, only a small part of the
code is time-critical enough to require the efficiency of compiled languages. The rest of
the code is generally related to memory management, error handling, input/output, and user
interaction, and those are usually the most error prone and time-consuming lines of code
to write and debug in the whole development process. Interpreted high-level languages can
be really advantageous for this kind of tasks.
For implementing general-purpose numerical computations, MATLAB [1] is the dominant
interpreted programming language. In the open source side, Octave and Scilab are well
known, freely distributed software packages providing compatibility with the MATLAB
language. In this work, we present MPI for Python, a new package enabling applications to
exploit multiple processors using standard MPI “look and feel” in Python scripts.
[1] MATLAB is a registered trademark of The MathWorks, Inc.
What is MPI?
MPI, [mpi-using] [mpi-ref] the Message Passing Interface, is a standardized and portable
message-passing system designed to function on a wide variety of parallel computers. The
standard defines the syntax and semantics of library routines and allows users to write
portable programs in the main scientific programming languages (Fortran, C, or C++).
Since its release, the MPI specification [mpi-std1] [mpi-std2] has become the leading
standard for message-passing libraries for parallel computers. Implementations are
available from vendors of high-performance computers and from well known open source
projects like MPICH [mpi-mpich] and Open MPI [mpi-openmpi].
What is Python?
Python is a modern, easy to learn, powerful programming language. It has efficient
high-level data structures and a simple but effective approach to object-oriented
programming with dynamic typing and dynamic binding. It supports modules and packages,
which encourages program modularity and code reuse. Python’s elegant syntax, together with
its interpreted nature, make it an ideal language for scripting and rapid application
development in many areas on most platforms.
The Python interpreter and the extensive standard library are available in source or
binary form without charge for all major platforms, and can be freely distributed. It is
easily extended with new functions and data types implemented in C or C++. Python is also
suitable as an extension language for customizable applications.
Python is an ideal candidate for writing the higher-level parts of large-scale scientific
applications [Hinsen97] and driving simulations in parallel architectures [Beazley97] like
clusters of PC’s or SMP’s. Python codes are quickly developed, easily maintained, and can
achieve a high degree of integration with other libraries written in compiled languages.
Related Projects
As this work started and evolved, some ideas were borrowed from well known MPI and Python
related open source projects from the Internet.
• OOMPI
• It has no relation with Python, but is an excellent object oriented approach to MPI.
• It is a C++ class library specification layered on top of the C bindings that
encapsulates MPI into a functional class hierarchy.
• It provides a flexible and intuitive interface by adding some abstractions, like Ports
and Messages, which enrich and simplify the syntax.
• Pypar
• Its interface is rather minimal. There is no support for communicators or process
topologies.
• It does not require the Python interpreter to be modified or recompiled, but does not
permit interactive parallel runs.
• General (picklable) Python objects of any type can be communicated. There is good
support for numeric arrays, practically full MPI bandwidth can be achieved.
• pyMPI
• It rebuilds the Python interpreter providing a built-in module for message passing. It
does permit interactive parallel runs, which are useful for learning and debugging.
• It provides an interface suitable for basic parallel programing. There is not full
support for defining new communicators or process topologies.
• General (picklable) Python objects can be messaged between processors. There is not
support for numeric arrays.
• Scientific Python
• It provides a collection of Python modules that are useful for scientific computing.
• There is an interface to MPI and BSP (Bulk Synchronous Parallel programming).
• The interface is simple but incomplete and does not resemble the MPI specification.
There is support for numeric arrays.
Additionally, we would like to mention some available tools for scientific computing and
software development with Python.
• NumPy is a package that provides array manipulation and computational capabilities
similar to those found in IDL, MATLAB, or Octave. Using NumPy, it is possible to write
many efficient numerical data processing applications directly in Python without using
any C, C++ or Fortran code.
• SciPy is an open source library of scientific tools for Python, gathering a variety of
high level science and engineering modules together as a single package. It includes
modules for graphics and plotting, optimization, integration, special functions, signal
and image processing, genetic algorithms, ODE solvers, and others.
• Cython is a language that makes writing C extensions for the Python language as easy as
Python itself. The Cython language is very close to the Python language, but Cython
additionally supports calling C functions and declaring C types on variables and class
attributes. This allows the compiler to generate very efficient C code from Cython code.
This makes Cython the ideal language for wrapping for external C libraries, and for fast
C modules that speed up the execution of Python code.
• SWIG is a software development tool that connects programs written in C and C++ with a
variety of high-level programming languages like Perl, Tcl/Tk, Ruby and Python. Issuing
header files to SWIG is the simplest approach to interfacing C/C++ libraries from a
Python module.
[mpi-std1]
MPI Forum. MPI: A Message Passing Interface Standard. International Journal of
Supercomputer Applications, volume 8, number 3-4, pages 159-416, 1994.
[mpi-std2]
MPI Forum. MPI: A Message Passing Interface Standard. High Performance Computing
Applications, volume 12, number 1-2, pages 1-299, 1998.
[mpi-using]
William Gropp, Ewing Lusk, and Anthony Skjellum. Using MPI: portable parallel
programming with the message-passing interface. MIT Press, 1994.
[mpi-ref]
Mark Snir, Steve Otto, Steven Huss-Lederman, David Walker, and Jack Dongarra. MPI -
The Complete Reference, volume 1, The MPI Core. MIT Press, 2nd. edition, 1998.
[mpi-mpich]
W. Gropp, E. Lusk, N. Doss, and A. Skjellum. A high-performance, portable
implementation of the MPI message passing interface standard. Parallel Computing,
22(6):789-828, September 1996.
[mpi-openmpi]
Edgar Gabriel, Graham E. Fagg, George Bosilca, Thara Angskun, Jack J. Dongarra,
Jeffrey M. Squyres, Vishal Sahay, Prabhanjan Kambadur, Brian Barrett, Andrew
Lumsdaine, Ralph H. Castain, David J. Daniel, Richard L. Graham, and Timothy S.
Woodall. Open MPI: Goals, Concept, and Design of a Next Generation MPI
Implementation. In Proceedings, 11th European PVM/MPI Users’ Group Meeting, Budapest,
Hungary, September 2004.
[Hinsen97]
Konrad Hinsen. The Molecular Modelling Toolkit: a case study of a large scientific
application in Python. In Proceedings of the 6th International Python Conference,
pages 29-35, San Jose, Ca., October 1997.
[Beazley97]
David M. Beazley and Peter S. Lomdahl. Feeding a large-scale physics application to
Python. In Proceedings of the 6th International Python Conference, pages 21-29, San
Jose, Ca., October 1997.
OVERVIEW
MPI for Python provides an object oriented approach to message passing which grounds on
the standard MPI-2 C++ bindings. The interface was designed with focus in translating MPI
syntax and semantics of standard MPI-2 bindings for C++ to Python. Any user of the
standard C/C++ MPI bindings should be able to use this module without need of learning a
new interface.
Communicating Python Objects and Array Data
The Python standard library supports different mechanisms for data persistence. Many of
them rely on disk storage, but pickling and marshaling can also work with memory buffers.
The pickle modules provide user-extensible facilities to serialize general Python objects
using ASCII or binary formats. The marshal module provides facilities to serialize
built-in Python objects using a binary format specific to Python, but independent of
machine architecture issues.
MPI for Python can communicate any built-in or user-defined Python object taking advantage
of the features provided by the pickle module. These facilities will be routinely used to
build binary representations of objects to communicate (at sending processes), and
restoring them back (at receiving processes).
Although simple and general, the serialization approach (i.e., pickling and unpickling)
previously discussed imposes important overheads in memory as well as processor usage,
especially in the scenario of objects with large memory footprints being communicated.
Pickling general Python objects, ranging from primitive or container built-in types to
user-defined classes, necessarily requires computer resources. Processing is also needed
for dispatching the appropriate serialization method (that depends on the type of the
object) and doing the actual packing. Additional memory is always needed, and if its total
amount is not known a priori, many reallocations can occur. Indeed, in the case of large
numeric arrays, this is certainly unacceptable and precludes communication of objects
occupying half or more of the available memory resources.
MPI for Python supports direct communication of any object exporting the single-segment
buffer interface. This interface is a standard Python mechanism provided by some types
(e.g., strings and numeric arrays), allowing access in the C side to a contiguous memory
buffer (i.e., address and length) containing the relevant data. This feature, in
conjunction with the capability of constructing user-defined MPI datatypes describing
complicated memory layouts, enables the implementation of many algorithms involving
multidimensional numeric arrays (e.g., image processing, fast Fourier transforms, finite
difference schemes on structured Cartesian grids) directly in Python, with negligible
overhead, and almost as fast as compiled Fortran, C, or C++ codes.
Communicators
In MPI for Python, Comm is the base class of communicators. The Intracomm and Intercomm
classes are sublcasses of the Comm class. The Comm.Is_inter method (and Comm.Is_intra,
provided for convenience but not part of the MPI specification) is defined for
communicator objects and can be used to determine the particular communicator class.
The two predefined intracommunicator instances are available: COMM_SELF and COMM_WORLD.
From them, new communicators can be created as needed.
The number of processes in a communicator and the calling process rank can be respectively
obtained with methods Comm.Get_size and Comm.Get_rank. The associated process group can be
retrieved from a communicator by calling the Comm.Get_group method, which returns an
instance of the Group class. Set operations with Group objects like like Group.Union,
Group.Intersection and Group.Difference are fully supported, as well as the creation of
new communicators from these groups using Comm.Create and Comm.Create_group.
New communicator instances can be obtained with the Comm.Clone, Comm.Dup and Comm.Split
methods, as well methods Intracomm.Create_intercomm and Intercomm.Merge.
Virtual topologies (Cartcomm, Graphcomm and Distgraphcomm classes, which are
specializations of the Intracomm class) are fully supported. New instances can be obtained
from intracommunicator instances with factory methods Intracomm.Create_cart and
Intracomm.Create_graph.
Point-to-Point Communications
Point to point communication is a fundamental capability of message passing systems. This
mechanism enables the transmission of data between a pair of processes, one side sending,
the other receiving.
MPI provides a set of send and receive functions allowing the communication of typed data
with an associated tag. The type information enables the conversion of data
representation from one architecture to another in the case of heterogeneous computing
environments; additionally, it allows the representation of non-contiguous data layouts
and user-defined datatypes, thus avoiding the overhead of (otherwise unavoidable)
packing/unpacking operations. The tag information allows selectivity of messages at the
receiving end.
Blocking Communications
MPI provides basic send and receive functions that are blocking. These functions block
the caller until the data buffers involved in the communication can be safely reused by
the application program.
In MPI for Python, the Comm.Send, Comm.Recv and Comm.Sendrecv methods of communicator
objects provide support for blocking point-to-point communications within Intracomm and
Intercomm instances. These methods can communicate memory buffers. The variants Comm.send,
Comm.recv and Comm.sendrecv can communicate general Python objects.
Nonblocking Communications
On many systems, performance can be significantly increased by overlapping communication
and computation. This is particularly true on systems where communication can be executed
autonomously by an intelligent, dedicated communication controller.
MPI provides nonblocking send and receive functions. They allow the possible overlap of
communication and computation. Non-blocking communication always come in two parts:
posting functions, which begin the requested operation; and test-for-completion functions,
which allow to discover whether the requested operation has completed.
In MPI for Python, the Comm.Isend and Comm.Irecv methods initiate send and receive
operations, respectively. These methods return a Request instance, uniquely identifying
the started operation. Its completion can be managed using the Request.Test, Request.Wait
and Request.Cancel methods. The management of Request objects and associated memory
buffers involved in communication requires a careful, rather low-level coordination. Users
must ensure that objects exposing their memory buffers are not accessed at the Python
level while they are involved in nonblocking message-passing operations.
Persistent Communications
Often a communication with the same argument list is repeatedly executed within an inner
loop. In such cases, communication can be further optimized by using persistent
communication, a particular case of nonblocking communication allowing the reduction of
the overhead between processes and communication controllers. Furthermore , this kind of
optimization can also alleviate the extra call overheads associated to interpreted,
dynamic languages like Python.
In MPI for Python, the Comm.Send_init and Comm.Recv_init methods create persistent
requests for a send and receive operation, respectively. These methods return an instance
of the Prequest class, a subclass of the Request class. The actual communication can be
effectively started using the Prequest.Start method, and its completion can be managed as
previously described.
Collective Communications
Collective communications allow the transmittal of data between multiple processes of a
group simultaneously. The syntax and semantics of collective functions is consistent with
point-to-point communication. Collective functions communicate typed data, but messages
are not paired with an associated tag; selectivity of messages is implied in the calling
order. Additionally, collective functions come in blocking versions only.
The more commonly used collective communication operations are the following.
• Barrier synchronization across all group members.
• Global communication functions
• Broadcast data from one member to all members of a group.
• Gather data from all members to one member of a group.
• Scatter data from one member to all members of a group.
• Global reduction operations such as sum, maximum, minimum, etc.
In MPI for Python, the Comm.Bcast, Comm.Scatter, Comm.Gather, Comm.Allgather,
Comm.Alltoall methods provide support for collective communications of memory buffers. The
lower-case variants Comm.bcast, Comm.scatter, Comm.gather, Comm.allgather and
Comm.alltoall can communicate general Python objects. The vector variants (which can
communicate different amounts of data to each process) Comm.Scatterv, Comm.Gatherv,
Comm.Allgatherv, Comm.Alltoallv and Comm.Alltoallw are also supported, they can only
communicate objects exposing memory buffers.
Global reducion operations on memory buffers are accessible through the Comm.Reduce,
Comm.Reduce_scatter, Comm.Allreduce, Intracomm.Scan and Intracomm.Exscan methods. The
lower-case variants Comm.reduce, Comm.allreduce, Intracomm.scan and Intracomm.exscan can
communicate general Python objects; however, the actual required reduction computations
are performed sequentially at some process. All the predefined (i.e., SUM, PROD, MAX,
etc.) reduction operations can be applied.
Support for GPU-aware MPI
Several MPI implementations, including Open MPI and MVAPICH, support passing GPU pointers
to MPI calls to avoid explict data movement between the host and the device. On the Python
side, GPU arrays have been implemented by many libraries that need GPU computation, such
as CuPy, Numba, PyTorch, and PyArrow. In order to increase library interoperability, two
kinds of zero-copy data exchange protocols are defined and agreed upon: DLPack and CUDA
Array Interface. For example, a CuPy array can be passed to a Numba CUDA-jit kernel.
MPI for Python provides an experimental support for GPU-aware MPI. This feature requires:
1. mpi4py is built against a GPU-aware MPI library.
2. The Python GPU arrays are compliant with either of the protocols.
See the Tutorial section for further information. We note that
• Whether or not a MPI call can work for GPU arrays depends on the underlying MPI
implementation, not on mpi4py.
• This support is currently experimental and subject to change in the future.
Dynamic Process Management
In the context of the MPI-1 specification, a parallel application is static; that is, no
processes can be added to or deleted from a running application after it has been started.
Fortunately, this limitation was addressed in MPI-2. The new specification added a process
management model providing a basic interface between an application and external resources
and process managers.
This MPI-2 extension can be really useful, especially for sequential applications built on
top of parallel modules, or parallel applications with a client/server model. The MPI-2
process model provides a mechanism to create new processes and establish communication
between them and the existing MPI application. It also provides mechanisms to establish
communication between two existing MPI applications, even when one did not start the
other.
In MPI for Python, new independent process groups can be created by calling the
Intracomm.Spawn method within an intracommunicator. This call returns a new
intercommunicator (i.e., an Intercomm instance) at the parent process group. The child
process group can retrieve the matching intercommunicator by calling the Comm.Get_parent
class method. At each side, the new intercommunicator can be used to perform point to
point and collective communications between the parent and child groups of processes.
Alternatively, disjoint groups of processes can establish communication using a
client/server approach. Any server application must first call the Open_port function to
open a port and the Publish_name function to publish a provided service, and next call the
Intracomm.Accept method. Any client applications can first find a published service by
calling the Lookup_name function, which returns the port where a server can be contacted;
and next call the Intracomm.Connect method. Both Intracomm.Accept and Intracomm.Connect
methods return an Intercomm instance. When connection between client/server processes is
no longer needed, all of them must cooperatively call the Comm.Disconnect method.
Additionally, server applications should release resources by calling the Unpublish_name
and Close_port functions.
One-Sided Communications
One-sided communications (also called Remote Memory Access, RMA) supplements the
traditional two-sided, send/receive based MPI communication model with a one-sided,
put/get based interface. One-sided communication that can take advantage of the
capabilities of highly specialized network hardware. Additionally, this extension lowers
latency and software overhead in applications written using a shared-memory-like paradigm.
The MPI specification revolves around the use of objects called windows; they intuitively
specify regions of a process’s memory that have been made available for remote read and
write operations. The published memory blocks can be accessed through three functions for
put (remote send), get (remote write), and accumulate (remote update or reduction) data
items. A much larger number of functions support different synchronization styles; the
semantics of these synchronization operations are fairly complex.
In MPI for Python, one-sided operations are available by using instances of the Win class.
New window objects are created by calling the Win.Create method at all processes within a
communicator and specifying a memory buffer . When a window instance is no longer needed,
the Win.Free method should be called.
The three one-sided MPI operations for remote write, read and reduction are available
through calling the methods Win.Put, Win.Get, and Win.Accumulate respectively within a Win
instance. These methods need an integer rank identifying the target process and an
integer offset relative the base address of the remote memory block being accessed.
The one-sided operations read, write, and reduction are implicitly nonblocking, and must
be synchronized by using two primary modes. Active target synchronization requires the
origin process to call the Win.Start and Win.Complete methods at the origin process, and
target process cooperates by calling the Win.Post and Win.Wait methods. There is also a
collective variant provided by the Win.Fence method. Passive target synchronization is
more lenient, only the origin process calls the Win.Lock and Win.Unlock methods. Locks are
used to protect remote accesses to the locked remote window and to protect local
load/store accesses to a locked local window.
Parallel Input/Output
The POSIX standard provides a model of a widely portable file system. However, the
optimization needed for parallel input/output cannot be achieved with this generic
interface. In order to ensure efficiency and scalability, the underlying parallel
input/output system must provide a high-level interface supporting partitioning of file
data among processes and a collective interface supporting complete transfers of global
data structures between process memories and files. Additionally, further efficiencies can
be gained via support for asynchronous input/output, strided accesses to data, and control
over physical file layout on storage devices. This scenario motivated the inclusion in the
MPI-2 standard of a custom interface in order to support more elaborated parallel
input/output operations.
The MPI specification for parallel input/output revolves around the use objects called
files. As defined by MPI, files are not just contiguous byte streams. Instead, they are
regarded as ordered collections of typed data items. MPI supports sequential or random
access to any integral set of these items. Furthermore, files are opened collectively by a
group of processes.
The common patterns for accessing a shared file (broadcast, scatter, gather, reduction) is
expressed by using user-defined datatypes. Compared to the communication patterns of
point-to-point and collective communications, this approach has the advantage of added
flexibility and expressiveness. Data access operations (read and write) are defined for
different kinds of positioning (using explicit offsets, individual file pointers, and
shared file pointers), coordination (non-collective and collective), and synchronism
(blocking, nonblocking, and split collective with begin/end phases).
In MPI for Python, all MPI input/output operations are performed through instances of the
File class. File handles are obtained by calling the File.Open method at all processes
within a communicator and providing a file name and the intended access mode. After use,
they must be closed by calling the File.Close method. Files even can be deleted by
calling method File.Delete.
After creation, files are typically associated with a per-process view. The view defines
the current set of data visible and accessible from an open file as an ordered set of
elementary datatypes. This data layout can be set and queried with the File.Set_view and
File.Get_view methods respectively.
Actual input/output operations are achieved by many methods combining read and write calls
with different behavior regarding positioning, coordination, and synchronism. Summing up,
MPI for Python provides the thirty (30) methods defined in MPI-2 for reading from or
writing to files using explicit offsets or file pointers (individual or shared), in
blocking or nonblocking and collective or noncollective versions.
Environmental Management
Initialization and Exit
Module functions Init or Init_thread and Finalize provide MPI initialization and
finalization respectively. Module functions Is_initialized and Is_finalized provide the
respective tests for initialization and finalization.
NOTE:
MPI_Init() or MPI_Init_thread() is actually called when you import the MPI module from
the mpi4py package, but only if MPI is not already initialized. In such case, calling
Init or Init_thread from Python is expected to generate an MPI error, and in turn an
exception will be raised.
NOTE:
MPI_Finalize() is registered (by using Python C/API function Py_AtExit()) for being
automatically called when Python processes exit, but only if mpi4py actually
initialized MPI. Therefore, there is no need to call Finalize from Python to ensure MPI
finalization.
Implementation Information
• The MPI version number can be retrieved from module function Get_version. It returns a
two-integer tuple (version, subversion).
• The Get_processor_name function can be used to access the processor name.
• The values of predefined attributes attached to the world communicator can be obtained
by calling the Comm.Get_attr method within the COMM_WORLD instance.
Timers
MPI timer functionalities are available through the Wtime and Wtick functions.
Error Handling
In order facilitate handle sharing with other Python modules interfacing MPI-based
parallel libraries, the predefined MPI error handlers ERRORS_RETURN and ERRORS_ARE_FATAL
can be assigned to and retrieved from communicators using methods Comm.Set_errhandler and
Comm.Get_errhandler, and similarly for windows and files.
When the predefined error handler ERRORS_RETURN is set, errors returned from MPI calls
within Python code will raise an instance of the exception class Exception, which is a
subclass of the standard Python exception RuntimeError.
NOTE:
After import, mpi4py overrides the default MPI rules governing inheritance of error
handlers. The ERRORS_RETURN error handler is set in the predefined COMM_SELF and
COMM_WORLD communicators, as well as any new Comm, Win, or File instance created
through mpi4py. If you ever pass such handles to C/C++/Fortran library code, it is
recommended to set the ERRORS_ARE_FATAL error handler on them to ensure MPI errors do
not pass silently.
WARNING:
Importing with from mpi4py.MPI import * will cause a name clashing with the standard
Python Exception base class.
TUTORIAL
WARNING:
Under construction. Contributions very welcome!
TIP:
Rolf Rabenseifner at HLRS developed a comprehensive MPI-3.1/4.0 course with slides and
a large set of exercises including solutions. This material is available online for
self-study. The slides and exercises show the C, Fortran, and Python (mpi4py)
interfaces. For performance reasons, most Python exercises use NumPy arrays and
communication routines involving buffer-like objects.
TIP:
Victor Eijkhout at TACC authored the book Parallel Programming for Science and
Engineering. This book is available online in PDF and HTML formats. The book covers
parallel programming with MPI and OpenMP in C/C++ and Fortran, and MPI in Python using
mpi4py.
MPI for Python supports convenient, pickle-based communication of generic Python object as
well as fast, near C-speed, direct array data communication of buffer-provider objects
(e.g., NumPy arrays).
• Communication of generic Python objects
You have to use methods with all-lowercase names, like Comm.send, Comm.recv, Comm.bcast,
Comm.scatter, Comm.gather . An object to be sent is passed as a parameter to the
communication call, and the received object is simply the return value.
The Comm.isend and Comm.irecv methods return Request instances; completion of these
methods can be managed using the Request.test and Request.wait methods.
The Comm.recv and Comm.irecv methods may be passed a buffer object that can be
repeatedly used to receive messages avoiding internal memory allocation. This buffer
must be sufficiently large to accommodate the transmitted messages; hence, any buffer
passed to Comm.recv or Comm.irecv must be at least as long as the pickled data
transmitted to the receiver.
Collective calls like Comm.scatter, Comm.gather, Comm.allgather, Comm.alltoall expect a
single value or a sequence of Comm.size elements at the root or all process. They return
a single value, a list of Comm.size elements, or None.
NOTE:
MPI for Python uses the highest protocol version available in the Python runtime (see
the HIGHEST_PROTOCOL constant in the pickle module). The default protocol can be
changed at import time by setting the MPI4PY_PICKLE_PROTOCOL environment variable, or
at runtime by assigning a different value to the PROTOCOL attribute of the pickle
object within the MPI module.
• Communication of buffer-like objects
You have to use method names starting with an upper-case letter, like Comm.Send,
Comm.Recv, Comm.Bcast, Comm.Scatter, Comm.Gather.
In general, buffer arguments to these calls must be explicitly specified by using a
2/3-list/tuple like [data, MPI.DOUBLE], or [data, count, MPI.DOUBLE] (the former one
uses the byte-size of data and the extent of the MPI datatype to define count).
For vector collectives communication operations like Comm.Scatterv and Comm.Gatherv,
buffer arguments are specified as [data, count, displ, datatype], where count and displ
are sequences of integral values.
Automatic MPI datatype discovery for NumPy/GPU arrays and PEP-3118 buffers is supported,
but limited to basic C types (all C/C99-native signed/unsigned integral types and
single/double precision real/complex floating types) and availability of matching
datatypes in the underlying MPI implementation. In this case, the buffer-provider object
can be passed directly as a buffer argument, the count and MPI datatype will be
inferred.
If mpi4py is built against a GPU-aware MPI implementation, GPU arrays can be passed to
upper-case methods as long as they have either the __dlpack__ and __dlpack_device__
methods or the __cuda_array_interface__ attribute that are compliant with the respective
standard specifications. Moreover, only C-contiguous or Fortran-contiguous GPU arrays
are supported. It is important to note that GPU buffers must be fully ready before any
MPI routines operate on them to avoid race conditions. This can be ensured by using the
synchronization API of your array library. mpi4py does not have access to any
GPU-specific functionality and thus cannot perform this operation automatically for
users.
Running Python scripts with MPI
Most MPI programs can be run with the command mpiexec. In practice, running Python
programs looks like:
$ mpiexec -n 4 python script.py
to run the program with 4 processors.
Point-to-Point Communication
• Python objects (pickle under the hood):
from mpi4py import MPI
comm = MPI.COMM_WORLD
rank = comm.Get_rank()
if rank == 0:
data = {'a': 7, 'b': 3.14}
comm.send(data, dest=1, tag=11)
elif rank == 1:
data = comm.recv(source=0, tag=11)
• Python objects with non-blocking communication:
from mpi4py import MPI
comm = MPI.COMM_WORLD
rank = comm.Get_rank()
if rank == 0:
data = {'a': 7, 'b': 3.14}
req = comm.isend(data, dest=1, tag=11)
req.wait()
elif rank == 1:
req = comm.irecv(source=0, tag=11)
data = req.wait()
• NumPy arrays (the fast way!):
from mpi4py import MPI
import numpy
comm = MPI.COMM_WORLD
rank = comm.Get_rank()
# passing MPI datatypes explicitly
if rank == 0:
data = numpy.arange(1000, dtype='i')
comm.Send([data, MPI.INT], dest=1, tag=77)
elif rank == 1:
data = numpy.empty(1000, dtype='i')
comm.Recv([data, MPI.INT], source=0, tag=77)
# automatic MPI datatype discovery
if rank == 0:
data = numpy.arange(100, dtype=numpy.float64)
comm.Send(data, dest=1, tag=13)
elif rank == 1:
data = numpy.empty(100, dtype=numpy.float64)
comm.Recv(data, source=0, tag=13)
Collective Communication
• Broadcasting a Python dictionary:
from mpi4py import MPI
comm = MPI.COMM_WORLD
rank = comm.Get_rank()
if rank == 0:
data = {'key1' : [7, 2.72, 2+3j],
'key2' : ( 'abc', 'xyz')}
else:
data = None
data = comm.bcast(data, root=0)
• Scattering Python objects:
from mpi4py import MPI
comm = MPI.COMM_WORLD
size = comm.Get_size()
rank = comm.Get_rank()
if rank == 0:
data = [(i+1)**2 for i in range(size)]
else:
data = None
data = comm.scatter(data, root=0)
assert data == (rank+1)**2
• Gathering Python objects:
from mpi4py import MPI
comm = MPI.COMM_WORLD
size = comm.Get_size()
rank = comm.Get_rank()
data = (rank+1)**2
data = comm.gather(data, root=0)
if rank == 0:
for i in range(size):
assert data[i] == (i+1)**2
else:
assert data is None
• Broadcasting a NumPy array:
from mpi4py import MPI
import numpy as np
comm = MPI.COMM_WORLD
rank = comm.Get_rank()
if rank == 0:
data = np.arange(100, dtype='i')
else:
data = np.empty(100, dtype='i')
comm.Bcast(data, root=0)
for i in range(100):
assert data[i] == i
• Scattering NumPy arrays:
from mpi4py import MPI
import numpy as np
comm = MPI.COMM_WORLD
size = comm.Get_size()
rank = comm.Get_rank()
sendbuf = None
if rank == 0:
sendbuf = np.empty([size, 100], dtype='i')
sendbuf.T[:,:] = range(size)
recvbuf = np.empty(100, dtype='i')
comm.Scatter(sendbuf, recvbuf, root=0)
assert np.allclose(recvbuf, rank)
• Gathering NumPy arrays:
from mpi4py import MPI
import numpy as np
comm = MPI.COMM_WORLD
size = comm.Get_size()
rank = comm.Get_rank()
sendbuf = np.zeros(100, dtype='i') + rank
recvbuf = None
if rank == 0:
recvbuf = np.empty([size, 100], dtype='i')
comm.Gather(sendbuf, recvbuf, root=0)
if rank == 0:
for i in range(size):
assert np.allclose(recvbuf[i,:], i)
• Parallel matrix-vector product:
from mpi4py import MPI
import numpy
def matvec(comm, A, x):
m = A.shape[0] # local rows
p = comm.Get_size()
xg = numpy.zeros(m*p, dtype='d')
comm.Allgather([x, MPI.DOUBLE],
[xg, MPI.DOUBLE])
y = numpy.dot(A, xg)
return y
MPI-IO
• Collective I/O with NumPy arrays:
from mpi4py import MPI
import numpy as np
amode = MPI.MODE_WRONLY|MPI.MODE_CREATE
comm = MPI.COMM_WORLD
fh = MPI.File.Open(comm, "./datafile.contig", amode)
buffer = np.empty(10, dtype=np.int)
buffer[:] = comm.Get_rank()
offset = comm.Get_rank()*buffer.nbytes
fh.Write_at_all(offset, buffer)
fh.Close()
• Non-contiguous Collective I/O with NumPy arrays and datatypes:
from mpi4py import MPI
import numpy as np
comm = MPI.COMM_WORLD
rank = comm.Get_rank()
size = comm.Get_size()
amode = MPI.MODE_WRONLY|MPI.MODE_CREATE
fh = MPI.File.Open(comm, "./datafile.noncontig", amode)
item_count = 10
buffer = np.empty(item_count, dtype='i')
buffer[:] = rank
filetype = MPI.INT.Create_vector(item_count, 1, size)
filetype.Commit()
displacement = MPI.INT.Get_size()*rank
fh.Set_view(displacement, filetype=filetype)
fh.Write_all(buffer)
filetype.Free()
fh.Close()
Dynamic Process Management
• Compute Pi - Master (or parent, or client) side:
#!/usr/bin/env python
from mpi4py import MPI
import numpy
import sys
comm = MPI.COMM_SELF.Spawn(sys.executable,
args=['cpi.py'],
maxprocs=5)
N = numpy.array(100, 'i')
comm.Bcast([N, MPI.INT], root=MPI.ROOT)
PI = numpy.array(0.0, 'd')
comm.Reduce(None, [PI, MPI.DOUBLE],
op=MPI.SUM, root=MPI.ROOT)
print(PI)
comm.Disconnect()
• Compute Pi - Worker (or child, or server) side:
#!/usr/bin/env python
from mpi4py import MPI
import numpy
comm = MPI.Comm.Get_parent()
size = comm.Get_size()
rank = comm.Get_rank()
N = numpy.array(0, dtype='i')
comm.Bcast([N, MPI.INT], root=0)
h = 1.0 / N; s = 0.0
for i in range(rank, N, size):
x = h * (i + 0.5)
s += 4.0 / (1.0 + x**2)
PI = numpy.array(s * h, dtype='d')
comm.Reduce([PI, MPI.DOUBLE], None,
op=MPI.SUM, root=0)
comm.Disconnect()
CUDA-aware MPI + Python GPU arrays
• Reduce-to-all CuPy arrays:
from mpi4py import MPI
import cupy as cp
comm = MPI.COMM_WORLD
size = comm.Get_size()
rank = comm.Get_rank()
sendbuf = cp.arange(10, dtype='i')
recvbuf = cp.empty_like(sendbuf)
assert hasattr(sendbuf, '__cuda_array_interface__')
assert hasattr(recvbuf, '__cuda_array_interface__')
cp.cuda.get_current_stream().synchronize()
comm.Allreduce(sendbuf, recvbuf)
assert cp.allclose(recvbuf, sendbuf*size)
One-Sided Communications
• Read from (write to) the entire RMA window:
import numpy as np
from mpi4py import MPI
from mpi4py.util import dtlib
comm = MPI.COMM_WORLD
rank = comm.Get_rank()
datatype = MPI.FLOAT
np_dtype = dtlib.to_numpy_dtype(datatype)
itemsize = datatype.Get_size()
N = 10
win_size = N * itemsize if rank == 0 else 0
win = MPI.Win.Allocate(win_size, comm=comm)
buf = np.empty(N, dtype=np_dtype)
if rank == 0:
buf.fill(42)
win.Lock(rank=0)
win.Put(buf, target_rank=0)
win.Unlock(rank=0)
comm.Barrier()
else:
comm.Barrier()
win.Lock(rank=0)
win.Get(buf, target_rank=0)
win.Unlock(rank=0)
assert np.all(buf == 42)
• Accessing a part of the RMA window using the target argument, which is defined as
(offset, count, datatype):
import numpy as np
from mpi4py import MPI
from mpi4py.util import dtlib
comm = MPI.COMM_WORLD
rank = comm.Get_rank()
datatype = MPI.FLOAT
np_dtype = dtlib.to_numpy_dtype(datatype)
itemsize = datatype.Get_size()
N = comm.Get_size() + 1
win_size = N * itemsize if rank == 0 else 0
win = MPI.Win.Allocate(
size=win_size,
disp_unit=itemsize,
comm=comm,
)
if rank == 0:
mem = np.frombuffer(win, dtype=np_dtype)
mem[:] = np.arange(len(mem), dtype=np_dtype)
comm.Barrier()
buf = np.zeros(3, dtype=np_dtype)
target = (rank, 2, datatype)
win.Lock(rank=0)
win.Get(buf, target_rank=0, target=target)
win.Unlock(rank=0)
assert np.all(buf == [rank, rank+1, 0])
Wrapping with SWIG
• C source:
/* file: helloworld.c */
void sayhello(MPI_Comm comm)
{
int size, rank;
MPI_Comm_size(comm, &size);
MPI_Comm_rank(comm, &rank);
printf("Hello, World! "
"I am process %d of %d.\n",
rank, size);
}
• SWIG interface file:
// file: helloworld.i
%module helloworld
%{
#include <mpi.h>
#include "helloworld.c"
}%
%include mpi4py/mpi4py.i
%mpi4py_typemap(Comm, MPI_Comm);
void sayhello(MPI_Comm comm);
• Try it in the Python prompt:
>>> from mpi4py import MPI
>>> import helloworld
>>> helloworld.sayhello(MPI.COMM_WORLD)
Hello, World! I am process 0 of 1.
Wrapping with F2Py
• Fortran 90 source:
! file: helloworld.f90
subroutine sayhello(comm)
use mpi
implicit none
integer :: comm, rank, size, ierr
call MPI_Comm_size(comm, size, ierr)
call MPI_Comm_rank(comm, rank, ierr)
print *, 'Hello, World! I am process ',rank,' of ',size,'.'
end subroutine sayhello
• Compiling example using f2py
$ f2py -c --f90exec=mpif90 helloworld.f90 -m helloworld
• Try it in the Python prompt:
>>> from mpi4py import MPI
>>> import helloworld
>>> fcomm = MPI.COMM_WORLD.py2f()
>>> helloworld.sayhello(fcomm)
Hello, World! I am process 0 of 1.
MPI4PY
This is the MPI for Python package.
The Message Passing Interface (MPI) is a standardized and portable message-passing system
designed to function on a wide variety of parallel computers. The MPI standard defines the
syntax and semantics of library routines and allows users to write portable programs in
the main scientific programming languages (Fortran, C, or C++). Since its release, the MPI
specification has become the leading standard for message-passing libraries for parallel
computers.
MPI for Python provides MPI bindings for the Python programming language, allowing any
Python program to exploit multiple processors. This package build on the MPI
specification and provides an object oriented interface which closely follows MPI-2 C++
bindings.
Runtime configuration options
mpi4py.rc
This object has attributes exposing runtime configuration options that become
effective at import time of the MPI module.
Attributes Summary
┌─────────────┬──────────────────────────────────┐
│initialize │ Automatic MPI initialization at │
│ │ import │
├─────────────┼──────────────────────────────────┤
│threads │ Request initialization with │
│ │ thread support │
├─────────────┼──────────────────────────────────┤
│thread_level │ Level of thread support to │
│ │ request │
├─────────────┼──────────────────────────────────┤
│finalize │ Automatic MPI finalization at │
│ │ exit │
├─────────────┼──────────────────────────────────┤
│fast_reduce │ Use tree-based reductions for │
│ │ objects │
├─────────────┼──────────────────────────────────┤
│recv_mprobe │ Use matched probes to receive │
│ │ objects │
├─────────────┼──────────────────────────────────┤
│errors │ Error handling policy │
└─────────────┴──────────────────────────────────┘
Attributes Documentation
mpi4py.rc.initialize
Automatic MPI initialization at import.
Type bool
Default
True
SEE ALSO:
MPI4PY_RC_INITIALIZE
mpi4py.rc.threads
Request initialization with thread support.
Type bool
Default
True
SEE ALSO:
MPI4PY_RC_THREADS
mpi4py.rc.thread_level
Level of thread support to request.
Type str
Default
"multiple"
Choices
"multiple", "serialized", "funneled", "single"
SEE ALSO:
MPI4PY_RC_THREAD_LEVEL
mpi4py.rc.finalize
Automatic MPI finalization at exit.
Type None or bool
Default
None
SEE ALSO:
MPI4PY_RC_FINALIZE
mpi4py.rc.fast_reduce
Use tree-based reductions for objects.
Type bool
Default
True
SEE ALSO:
MPI4PY_RC_FAST_REDUCE
mpi4py.rc.recv_mprobe
Use matched probes to receive objects.
Type bool
Default
True
SEE ALSO:
MPI4PY_RC_RECV_MPROBE
mpi4py.rc.errors
Error handling policy.
Type str
Default
"exception"
Choices
"exception", "default", "fatal"
SEE ALSO:
MPI4PY_RC_ERRORS
Example
MPI for Python features automatic initialization and finalization of the MPI execution
environment. By using the mpi4py.rc object, MPI initialization and finalization can be
handled programatically:
import mpi4py
mpi4py.rc.initialize = False # do not initialize MPI automatically
mpi4py.rc.finalize = False # do not finalize MPI automatically
from mpi4py import MPI # import the 'MPI' module
MPI.Init() # manual initialization of the MPI environment
... # your finest code here ...
MPI.Finalize() # manual finalization of the MPI environment
Environment variables
The following environment variables override the corresponding attributes of the mpi4py.rc
and MPI.pickle objects at import time of the MPI module.
NOTE:
For variables of boolean type, accepted values are 0 and 1 (interpreted as False and ‐
True, respectively), and strings specifying a YAML boolean value (case-insensitive).
MPI4PY_RC_INITIALIZE
Type bool
Default
True
Whether to automatically initialize MPI at import time of the mpi4py.MPI module.
SEE ALSO:
mpi4py.rc.initialize
Added in version 3.1.0.
MPI4PY_RC_FINALIZE
Type None | bool
Default
None
Choices
None, True, False
Whether to automatically finalize MPI at exit time of the Python process.
SEE ALSO:
mpi4py.rc.finalize
Added in version 3.1.0.
MPI4PY_RC_THREADS
Type bool
Default
True
Whether to initialize MPI with thread support.
SEE ALSO:
mpi4py.rc.threads
Added in version 3.1.0.
MPI4PY_RC_THREAD_LEVEL
Default
"multiple"
Choices
"single", "funneled", "serialized", "multiple"
The level of required thread support.
SEE ALSO:
mpi4py.rc.thread_level
Added in version 3.1.0.
MPI4PY_RC_FAST_REDUCE
Type bool
Default
True
Whether to use tree-based reductions for objects.
SEE ALSO:
mpi4py.rc.fast_reduce
Added in version 3.1.0.
MPI4PY_RC_RECV_MPROBE
Type bool
Default
True
Whether to use matched probes to receive objects.
SEE ALSO:
mpi4py.rc.recv_mprobe
MPI4PY_RC_ERRORS
Default
"exception"
Choices
"exception", "default", "fatal"
Controls default MPI error handling policy.
SEE ALSO:
mpi4py.rc.errors
Added in version 3.1.0.
MPI4PY_PICKLE_PROTOCOL
Type int
Default
pickle.HIGHEST_PROTOCOL
Controls the default pickle protocol to use when communicating Python objects.
SEE ALSO:
PROTOCOL attribute of the MPI.pickle object within the MPI module.
Added in version 3.1.0.
MPI4PY_PICKLE_THRESHOLD
Type int
Default
262144
Controls the default buffer size threshold for switching from in-band to
out-of-band buffer handling when using pickle protocol version 5 or higher.
SEE ALSO:
Module mpi4py.util.pkl5.
Added in version 3.1.2.
Miscellaneous functions
mpi4py.profile(name, *, path=None, logfile=None)
Support for the MPI profiling interface.
Parameters
• name (str) – Name of the profiler library to load.
• path (sequence of str, optional) – Additional paths to search for the
profiler.
• logfile (str, optional) – Filename prefix for dumping profiler output.
Return type
None
mpi4py.get_config()
Return a dictionary with information about MPI.
Return type
Dict[str, str]
mpi4py.get_include()
Return the directory in the package that contains header files.
Extension modules that need to compile against mpi4py should use this function to
locate the appropriate include directory. Using Python distutils (or perhaps NumPy
distutils):
import mpi4py
Extension('extension_name', ...
include_dirs=[..., mpi4py.get_include()])
Return type
str
MPI4PY.MPI
Classes
Ancillary
┌─────────────────────┬────────────────────────────┐
│Datatype([datatype]) │ Datatype object │
├─────────────────────┼────────────────────────────┤
│Status([status]) │ Status object │
├─────────────────────┼────────────────────────────┤
│Request([request]) │ Request handle │
├─────────────────────┼────────────────────────────┤
│Prequest([request]) │ Persistent request handle │
├─────────────────────┼────────────────────────────┤
│Grequest([request]) │ Generalized request handle │
├─────────────────────┼────────────────────────────┤
│Op([op]) │ Operation object │
├─────────────────────┼────────────────────────────┤
│Group([group]) │ Group of processes │
├─────────────────────┼────────────────────────────┤
│Info([info]) │ Info object │
└─────────────────────┴────────────────────────────┘
Communication
┌──────────────────────┬──────────────────────────────────┐
│Comm([comm]) │ Communicator │
├──────────────────────┼──────────────────────────────────┤
│Intracomm([comm]) │ Intracommunicator │
├──────────────────────┼──────────────────────────────────┤
│Topocomm([comm]) │ Topology intracommunicator │
├──────────────────────┼──────────────────────────────────┤
│Cartcomm([comm]) │ Cartesian topology │
│ │ intracommunicator │
├──────────────────────┼──────────────────────────────────┤
│Graphcomm([comm]) │ General graph topology │
│ │ intracommunicator │
├──────────────────────┼──────────────────────────────────┤
│Distgraphcomm([comm]) │ Distributed graph topology │
│ │ intracommunicator │
├──────────────────────┼──────────────────────────────────┤
│Intercomm([comm]) │ Intercommunicator │
├──────────────────────┼──────────────────────────────────┤
│Message([message]) │ Matched message handle │
└──────────────────────┴──────────────────────────────────┘
One-sided operations
┌───────────┬───────────────┐
│Win([win]) │ Window handle │
└───────────┴───────────────┘
Input/Output
┌─────────────┬─────────────┐
│File([file]) │ File handle │
└─────────────┴─────────────┘
Error handling
┌─────────────────────────┬─────────────────┐
│Errhandler([errhandler]) │ Error handler │
├─────────────────────────┼─────────────────┤
│Exception([ierr]) │ Exception class │
└─────────────────────────┴─────────────────┘
Auxiliary
┌─────────────────────────────────┬────────────────────────────────┐
│Pickle([dumps, loads, protocol]) │ Pickle/unpickle Python objects │
├─────────────────────────────────┼────────────────────────────────┤
│memory(buf) │ Memory buffer │
└─────────────────────────────────┴────────────────────────────────┘
Functions
Version inquiry
┌──────────────────────┬──────────────────────────────────┐
│Get_version() │ Obtain the version number of the │
│ │ MPI standard supported by the │
│ │ implementation as a tuple │
│ │ (version, subversion) │
├──────────────────────┼──────────────────────────────────┤
│Get_library_version() │ Obtain the version string of the │
│ │ MPI library │
└──────────────────────┴──────────────────────────────────┘
Initialization and finalization
┌────────────────────────┬──────────────────────────────────┐
│Init() │ Initialize the MPI execution │
│ │ environment │
├────────────────────────┼──────────────────────────────────┤
│Init_thread([required]) │ Initialize the MPI execution │
│ │ environment │
├────────────────────────┼──────────────────────────────────┤
│Finalize() │ Terminate the MPI execution │
│ │ environment │
├────────────────────────┼──────────────────────────────────┤
│Is_initialized() │ Indicates whether Init has been │
│ │ called │
├────────────────────────┼──────────────────────────────────┤
│Is_finalized() │ Indicates whether Finalize has │
│ │ completed │
├────────────────────────┼──────────────────────────────────┤
│Query_thread() │ Return the level of thread │
│ │ support provided by the MPI │
│ │ library │
├────────────────────────┼──────────────────────────────────┤
│Is_thread_main() │ Indicate whether this thread │
│ │ called Init or Init_thread │
└────────────────────────┴──────────────────────────────────┘
Memory allocation
┌────────────────────────┬──────────────────────────────────┐
│Alloc_mem(size[, info]) │ Allocate memory for message │
│ │ passing and RMA │
├────────────────────────┼──────────────────────────────────┤
│Free_mem(mem) │ Free memory allocated with │
│ │ Alloc_mem() │
└────────────────────────┴──────────────────────────────────┘
Address manipulation
┌────────────────────────┬──────────────────────────────────┐
│Get_address(location) │ Get the address of a location in │
│ │ memory │
├────────────────────────┼──────────────────────────────────┤
│Aint_add(base, disp) │ Return the sum of base address │
│ │ and displacement │
├────────────────────────┼──────────────────────────────────┤
│Aint_diff(addr1, addr2) │ Return the difference between │
│ │ absolute addresses │
└────────────────────────┴──────────────────────────────────┘
Timer
┌────────┬──────────────────────────────────┐
│Wtick() │ Return the resolution of Wtime │
├────────┼──────────────────────────────────┤
│Wtime() │ Return an elapsed time on the │
│ │ calling processor │
└────────┴──────────────────────────────────┘
Error handling
┌────────────────────────────┬──────────────────────────────────┐
│Get_error_class(errorcode) │ Convert an error code into an │
│ │ error class │
├────────────────────────────┼──────────────────────────────────┤
│Get_error_string(errorcode) │ Return the error string for a │
│ │ given error class or error code │
├────────────────────────────┼──────────────────────────────────┤
│Add_error_class() │ Add an error class to the known │
│ │ error classes │
├────────────────────────────┼──────────────────────────────────┤
│Add_error_code(errorclass) │ Add an error code to an error │
│ │ class │
├────────────────────────────┼──────────────────────────────────┤
│Add_error_string(errorcode, │ Associate an error string with │
│string) │ an error class or errorcode │
└────────────────────────────┴──────────────────────────────────┘
Dynamic process management
┌─────────────────────────────┬──────────────────────────────────┐
│Open_port([info]) │ Return an address that can be │
│ │ used to establish connections │
│ │ between groups of MPI processes │
├─────────────────────────────┼──────────────────────────────────┤
│Close_port(port_name) │ Close a port │
├─────────────────────────────┼──────────────────────────────────┤
│Publish_name(service_name, │ Publish a service name │
│port_name[, info]) │ │
├─────────────────────────────┼──────────────────────────────────┤
│Unpublish_name(service_name, │ Unpublish a service name │
│port_name[, info]) │ │
├─────────────────────────────┼──────────────────────────────────┤
│Lookup_name(service_name[, │ Lookup a port name given a │
│info]) │ service name │
└─────────────────────────────┴──────────────────────────────────┘
Miscellanea
┌───────────────────────────┬──────────────────────────────────┐
│Attach_buffer(buf) │ Attach a user-provided buffer │
│ │ for sending in buffered mode │
├───────────────────────────┼──────────────────────────────────┤
│Detach_buffer() │ Remove an existing attached │
│ │ buffer │
├───────────────────────────┼──────────────────────────────────┤
│Compute_dims(nnodes, dims) │ Return a balanced distribution │
│ │ of processes per coordinate │
│ │ direction │
├───────────────────────────┼──────────────────────────────────┤
│Get_processor_name() │ Obtain the name of the calling │
│ │ processor │
├───────────────────────────┼──────────────────────────────────┤
│Register_datarep(datarep, │ Register user-defined data │
│read_fn, write_fn, ...) │ representations │
├───────────────────────────┼──────────────────────────────────┤
│Pcontrol(level) │ Control profiling │
└───────────────────────────┴──────────────────────────────────┘
Utilities
┌─────────────┬──────────────────────────────────┐
│get_vendor() │ Infomation about the underlying │
│ │ MPI implementation │
└─────────────┴──────────────────────────────────┘
Attributes
┌───────────────────────────┬──────────────────────────────────┐
│UNDEFINED │ int UNDEFINED │
├───────────────────────────┼──────────────────────────────────┤
│ANY_SOURCE │ int ANY_SOURCE │
├───────────────────────────┼──────────────────────────────────┤
│ANY_TAG │ int ANY_TAG │
├───────────────────────────┼──────────────────────────────────┤
│PROC_NULL │ int PROC_NULL │
├───────────────────────────┼──────────────────────────────────┤
│ROOT │ int ROOT │
├───────────────────────────┼──────────────────────────────────┤
│BOTTOM │ Bottom BOTTOM │
├───────────────────────────┼──────────────────────────────────┤
│IN_PLACE │ InPlace IN_PLACE │
├───────────────────────────┼──────────────────────────────────┤
│KEYVAL_INVALID │ int KEYVAL_INVALID │
├───────────────────────────┼──────────────────────────────────┤
│TAG_UB │ int TAG_UB │
├───────────────────────────┼──────────────────────────────────┤
│HOST │ int HOST │
├───────────────────────────┼──────────────────────────────────┤
│IO │ int IO │
├───────────────────────────┼──────────────────────────────────┤
│WTIME_IS_GLOBAL │ int WTIME_IS_GLOBAL │
├───────────────────────────┼──────────────────────────────────┤
│UNIVERSE_SIZE │ int UNIVERSE_SIZE │
├───────────────────────────┼──────────────────────────────────┤
│APPNUM │ int APPNUM │
├───────────────────────────┼──────────────────────────────────┤
│LASTUSEDCODE │ int LASTUSEDCODE │
├───────────────────────────┼──────────────────────────────────┤
│WIN_BASE │ int WIN_BASE │
├───────────────────────────┼──────────────────────────────────┤
│WIN_SIZE │ int WIN_SIZE │
├───────────────────────────┼──────────────────────────────────┤
│WIN_DISP_UNIT │ int WIN_DISP_UNIT │
├───────────────────────────┼──────────────────────────────────┤
│WIN_CREATE_FLAVOR │ int WIN_CREATE_FLAVOR │
├───────────────────────────┼──────────────────────────────────┤
│WIN_FLAVOR │ int WIN_FLAVOR │
├───────────────────────────┼──────────────────────────────────┤
│WIN_MODEL │ int WIN_MODEL │
├───────────────────────────┼──────────────────────────────────┤
│SUCCESS │ int SUCCESS │
├───────────────────────────┼──────────────────────────────────┤
│ERR_LASTCODE │ int ERR_LASTCODE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_COMM │ int ERR_COMM │
├───────────────────────────┼──────────────────────────────────┤
│ERR_GROUP │ int ERR_GROUP │
├───────────────────────────┼──────────────────────────────────┤
│ERR_TYPE │ int ERR_TYPE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_REQUEST │ int ERR_REQUEST │
├───────────────────────────┼──────────────────────────────────┤
│ERR_OP │ int ERR_OP │
├───────────────────────────┼──────────────────────────────────┤
│ERR_BUFFER │ int ERR_BUFFER │
├───────────────────────────┼──────────────────────────────────┤
│ERR_COUNT │ int ERR_COUNT │
├───────────────────────────┼──────────────────────────────────┤
│ERR_TAG │ int ERR_TAG │
├───────────────────────────┼──────────────────────────────────┤
│ERR_RANK │ int ERR_RANK │
├───────────────────────────┼──────────────────────────────────┤
│ERR_ROOT │ int ERR_ROOT │
├───────────────────────────┼──────────────────────────────────┤
│ERR_TRUNCATE │ int ERR_TRUNCATE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_IN_STATUS │ int ERR_IN_STATUS │
├───────────────────────────┼──────────────────────────────────┤
│ERR_PENDING │ int ERR_PENDING │
├───────────────────────────┼──────────────────────────────────┤
│ERR_TOPOLOGY │ int ERR_TOPOLOGY │
├───────────────────────────┼──────────────────────────────────┤
│ERR_DIMS │ int ERR_DIMS │
├───────────────────────────┼──────────────────────────────────┤
│ERR_ARG │ int ERR_ARG │
├───────────────────────────┼──────────────────────────────────┤
│ERR_OTHER │ int ERR_OTHER │
├───────────────────────────┼──────────────────────────────────┤
│ERR_UNKNOWN │ int ERR_UNKNOWN │
├───────────────────────────┼──────────────────────────────────┤
│ERR_INTERN │ int ERR_INTERN │
├───────────────────────────┼──────────────────────────────────┤
│ERR_INFO │ int ERR_INFO │
├───────────────────────────┼──────────────────────────────────┤
│ERR_FILE │ int ERR_FILE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_WIN │ int ERR_WIN │
├───────────────────────────┼──────────────────────────────────┤
│ERR_KEYVAL │ int ERR_KEYVAL │
├───────────────────────────┼──────────────────────────────────┤
│ERR_INFO_KEY │ int ERR_INFO_KEY │
├───────────────────────────┼──────────────────────────────────┤
│ERR_INFO_VALUE │ int ERR_INFO_VALUE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_INFO_NOKEY │ int ERR_INFO_NOKEY │
├───────────────────────────┼──────────────────────────────────┤
│ERR_ACCESS │ int ERR_ACCESS │
├───────────────────────────┼──────────────────────────────────┤
│ERR_AMODE │ int ERR_AMODE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_BAD_FILE │ int ERR_BAD_FILE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_FILE_EXISTS │ int ERR_FILE_EXISTS │
├───────────────────────────┼──────────────────────────────────┤
│ERR_FILE_IN_USE │ int ERR_FILE_IN_USE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_NO_SPACE │ int ERR_NO_SPACE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_NO_SUCH_FILE │ int ERR_NO_SUCH_FILE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_IO │ int ERR_IO │
├───────────────────────────┼──────────────────────────────────┤
│ERR_READ_ONLY │ int ERR_READ_ONLY │
├───────────────────────────┼──────────────────────────────────┤
│ERR_CONVERSION │ int ERR_CONVERSION │
├───────────────────────────┼──────────────────────────────────┤
│ERR_DUP_DATAREP │ int ERR_DUP_DATAREP │
├───────────────────────────┼──────────────────────────────────┤
│ERR_UNSUPPORTED_DATAREP │ int ERR_UNSUPPORTED_DATAREP │
├───────────────────────────┼──────────────────────────────────┤
│ERR_UNSUPPORTED_OPERATION │ int ERR_UNSUPPORTED_OPERATION │
├───────────────────────────┼──────────────────────────────────┤
│ERR_NAME │ int ERR_NAME │
├───────────────────────────┼──────────────────────────────────┤
│ERR_NO_MEM │ int ERR_NO_MEM │
├───────────────────────────┼──────────────────────────────────┤
│ERR_NOT_SAME │ int ERR_NOT_SAME │
├───────────────────────────┼──────────────────────────────────┤
│ERR_PORT │ int ERR_PORT │
├───────────────────────────┼──────────────────────────────────┤
│ERR_QUOTA │ int ERR_QUOTA │
├───────────────────────────┼──────────────────────────────────┤
│ERR_SERVICE │ int ERR_SERVICE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_SPAWN │ int ERR_SPAWN │
├───────────────────────────┼──────────────────────────────────┤
│ERR_BASE │ int ERR_BASE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_SIZE │ int ERR_SIZE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_DISP │ int ERR_DISP │
├───────────────────────────┼──────────────────────────────────┤
│ERR_ASSERT │ int ERR_ASSERT │
├───────────────────────────┼──────────────────────────────────┤
│ERR_LOCKTYPE │ int ERR_LOCKTYPE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_RMA_CONFLICT │ int ERR_RMA_CONFLICT │
├───────────────────────────┼──────────────────────────────────┤
│ERR_RMA_SYNC │ int ERR_RMA_SYNC │
├───────────────────────────┼──────────────────────────────────┤
│ERR_RMA_RANGE │ int ERR_RMA_RANGE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_RMA_ATTACH │ int ERR_RMA_ATTACH │
├───────────────────────────┼──────────────────────────────────┤
│ERR_RMA_SHARED │ int ERR_RMA_SHARED │
├───────────────────────────┼──────────────────────────────────┤
│ERR_RMA_FLAVOR │ int ERR_RMA_FLAVOR │
├───────────────────────────┼──────────────────────────────────┤
│ORDER_C │ int ORDER_C │
├───────────────────────────┼──────────────────────────────────┤
│ORDER_F │ int ORDER_F │
├───────────────────────────┼──────────────────────────────────┤
│ORDER_FORTRAN │ int ORDER_FORTRAN │
├───────────────────────────┼──────────────────────────────────┤
│TYPECLASS_INTEGER │ int TYPECLASS_INTEGER │
├───────────────────────────┼──────────────────────────────────┤
│TYPECLASS_REAL │ int TYPECLASS_REAL │
├───────────────────────────┼──────────────────────────────────┤
│TYPECLASS_COMPLEX │ int TYPECLASS_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│DISTRIBUTE_NONE │ int DISTRIBUTE_NONE │
├───────────────────────────┼──────────────────────────────────┤
│DISTRIBUTE_BLOCK │ int DISTRIBUTE_BLOCK │
├───────────────────────────┼──────────────────────────────────┤
│DISTRIBUTE_CYCLIC │ int DISTRIBUTE_CYCLIC │
├───────────────────────────┼──────────────────────────────────┤
│DISTRIBUTE_DFLT_DARG │ int DISTRIBUTE_DFLT_DARG │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_NAMED │ int COMBINER_NAMED │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_DUP │ int COMBINER_DUP │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_CONTIGUOUS │ int COMBINER_CONTIGUOUS │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_VECTOR │ int COMBINER_VECTOR │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_HVECTOR │ int COMBINER_HVECTOR │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_INDEXED │ int COMBINER_INDEXED │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_HINDEXED │ int COMBINER_HINDEXED │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_INDEXED_BLOCK │ int COMBINER_INDEXED_BLOCK │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_HINDEXED_BLOCK │ int COMBINER_HINDEXED_BLOCK │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_STRUCT │ int COMBINER_STRUCT │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_SUBARRAY │ int COMBINER_SUBARRAY │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_DARRAY │ int COMBINER_DARRAY │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_RESIZED │ int COMBINER_RESIZED │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_F90_REAL │ int COMBINER_F90_REAL │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_F90_COMPLEX │ int COMBINER_F90_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_F90_INTEGER │ int COMBINER_F90_INTEGER │
├───────────────────────────┼──────────────────────────────────┤
│IDENT │ int IDENT │
├───────────────────────────┼──────────────────────────────────┤
│CONGRUENT │ int CONGRUENT │
├───────────────────────────┼──────────────────────────────────┤
│SIMILAR │ int SIMILAR │
├───────────────────────────┼──────────────────────────────────┤
│UNEQUAL │ int UNEQUAL │
├───────────────────────────┼──────────────────────────────────┤
│CART │ int CART │
├───────────────────────────┼──────────────────────────────────┤
│GRAPH │ int GRAPH │
├───────────────────────────┼──────────────────────────────────┤
│DIST_GRAPH │ int DIST_GRAPH │
├───────────────────────────┼──────────────────────────────────┤
│UNWEIGHTED │ int UNWEIGHTED │
├───────────────────────────┼──────────────────────────────────┤
│WEIGHTS_EMPTY │ int WEIGHTS_EMPTY │
├───────────────────────────┼──────────────────────────────────┤
│COMM_TYPE_SHARED │ int COMM_TYPE_SHARED │
├───────────────────────────┼──────────────────────────────────┤
│BSEND_OVERHEAD │ int BSEND_OVERHEAD │
├───────────────────────────┼──────────────────────────────────┤
│WIN_FLAVOR_CREATE │ int WIN_FLAVOR_CREATE │
├───────────────────────────┼──────────────────────────────────┤
│WIN_FLAVOR_ALLOCATE │ int WIN_FLAVOR_ALLOCATE │
├───────────────────────────┼──────────────────────────────────┤
│WIN_FLAVOR_DYNAMIC │ int WIN_FLAVOR_DYNAMIC │
├───────────────────────────┼──────────────────────────────────┤
│WIN_FLAVOR_SHARED │ int WIN_FLAVOR_SHARED │
├───────────────────────────┼──────────────────────────────────┤
│WIN_SEPARATE │ int WIN_SEPARATE │
├───────────────────────────┼──────────────────────────────────┤
│WIN_UNIFIED │ int WIN_UNIFIED │
├───────────────────────────┼──────────────────────────────────┤
│MODE_NOCHECK │ int MODE_NOCHECK │
├───────────────────────────┼──────────────────────────────────┤
│MODE_NOSTORE │ int MODE_NOSTORE │
├───────────────────────────┼──────────────────────────────────┤
│MODE_NOPUT │ int MODE_NOPUT │
├───────────────────────────┼──────────────────────────────────┤
│MODE_NOPRECEDE │ int MODE_NOPRECEDE │
├───────────────────────────┼──────────────────────────────────┤
│MODE_NOSUCCEED │ int MODE_NOSUCCEED │
├───────────────────────────┼──────────────────────────────────┤
│LOCK_EXCLUSIVE │ int LOCK_EXCLUSIVE │
├───────────────────────────┼──────────────────────────────────┤
│LOCK_SHARED │ int LOCK_SHARED │
├───────────────────────────┼──────────────────────────────────┤
│MODE_RDONLY │ int MODE_RDONLY │
├───────────────────────────┼──────────────────────────────────┤
│MODE_WRONLY │ int MODE_WRONLY │
├───────────────────────────┼──────────────────────────────────┤
│MODE_RDWR │ int MODE_RDWR │
├───────────────────────────┼──────────────────────────────────┤
│MODE_CREATE │ int MODE_CREATE │
├───────────────────────────┼──────────────────────────────────┤
│MODE_EXCL │ int MODE_EXCL │
├───────────────────────────┼──────────────────────────────────┤
│MODE_DELETE_ON_CLOSE │ int MODE_DELETE_ON_CLOSE │
├───────────────────────────┼──────────────────────────────────┤
│MODE_UNIQUE_OPEN │ int MODE_UNIQUE_OPEN │
├───────────────────────────┼──────────────────────────────────┤
│MODE_SEQUENTIAL │ int MODE_SEQUENTIAL │
├───────────────────────────┼──────────────────────────────────┤
│MODE_APPEND │ int MODE_APPEND │
├───────────────────────────┼──────────────────────────────────┤
│SEEK_SET │ int SEEK_SET │
├───────────────────────────┼──────────────────────────────────┤
│SEEK_CUR │ int SEEK_CUR │
├───────────────────────────┼──────────────────────────────────┤
│SEEK_END │ int SEEK_END │
├───────────────────────────┼──────────────────────────────────┤
│DISPLACEMENT_CURRENT │ int DISPLACEMENT_CURRENT │
├───────────────────────────┼──────────────────────────────────┤
│DISP_CUR │ int DISP_CUR │
├───────────────────────────┼──────────────────────────────────┤
│THREAD_SINGLE │ int THREAD_SINGLE │
├───────────────────────────┼──────────────────────────────────┤
│THREAD_FUNNELED │ int THREAD_FUNNELED │
├───────────────────────────┼──────────────────────────────────┤
│THREAD_SERIALIZED │ int THREAD_SERIALIZED │
├───────────────────────────┼──────────────────────────────────┤
│THREAD_MULTIPLE │ int THREAD_MULTIPLE │
├───────────────────────────┼──────────────────────────────────┤
│VERSION │ int VERSION │
├───────────────────────────┼──────────────────────────────────┤
│SUBVERSION │ int SUBVERSION │
├───────────────────────────┼──────────────────────────────────┤
│MAX_PROCESSOR_NAME │ int MAX_PROCESSOR_NAME │
├───────────────────────────┼──────────────────────────────────┤
│MAX_ERROR_STRING │ int MAX_ERROR_STRING │
├───────────────────────────┼──────────────────────────────────┤
│MAX_PORT_NAME │ int MAX_PORT_NAME │
├───────────────────────────┼──────────────────────────────────┤
│MAX_INFO_KEY │ int MAX_INFO_KEY │
├───────────────────────────┼──────────────────────────────────┤
│MAX_INFO_VAL │ int MAX_INFO_VAL │
├───────────────────────────┼──────────────────────────────────┤
│MAX_OBJECT_NAME │ int MAX_OBJECT_NAME │
├───────────────────────────┼──────────────────────────────────┤
│MAX_DATAREP_STRING │ int MAX_DATAREP_STRING │
├───────────────────────────┼──────────────────────────────────┤
│MAX_LIBRARY_VERSION_STRING │ int MAX_LIBRARY_VERSION_STRING │
├───────────────────────────┼──────────────────────────────────┤
│DATATYPE_NULL │ Datatype DATATYPE_NULL │
├───────────────────────────┼──────────────────────────────────┤
│UB │ Datatype UB │
├───────────────────────────┼──────────────────────────────────┤
│LB │ Datatype LB │
├───────────────────────────┼──────────────────────────────────┤
│PACKED │ Datatype PACKED │
├───────────────────────────┼──────────────────────────────────┤
│BYTE │ Datatype BYTE │
├───────────────────────────┼──────────────────────────────────┤
│AINT │ Datatype AINT │
├───────────────────────────┼──────────────────────────────────┤
│OFFSET │ Datatype OFFSET │
├───────────────────────────┼──────────────────────────────────┤
│COUNT │ Datatype COUNT │
├───────────────────────────┼──────────────────────────────────┤
│CHAR │ Datatype CHAR │
├───────────────────────────┼──────────────────────────────────┤
│WCHAR │ Datatype WCHAR │
├───────────────────────────┼──────────────────────────────────┤
│SIGNED_CHAR │ Datatype SIGNED_CHAR │
├───────────────────────────┼──────────────────────────────────┤
│SHORT │ Datatype SHORT │
├───────────────────────────┼──────────────────────────────────┤
│INT │ Datatype INT │
├───────────────────────────┼──────────────────────────────────┤
│LONG │ Datatype LONG │
├───────────────────────────┼──────────────────────────────────┤
│LONG_LONG │ Datatype LONG_LONG │
├───────────────────────────┼──────────────────────────────────┤
│UNSIGNED_CHAR │ Datatype UNSIGNED_CHAR │
├───────────────────────────┼──────────────────────────────────┤
│UNSIGNED_SHORT │ Datatype UNSIGNED_SHORT │
├───────────────────────────┼──────────────────────────────────┤
│UNSIGNED │ Datatype UNSIGNED │
├───────────────────────────┼──────────────────────────────────┤
│UNSIGNED_LONG │ Datatype UNSIGNED_LONG │
├───────────────────────────┼──────────────────────────────────┤
│UNSIGNED_LONG_LONG │ Datatype UNSIGNED_LONG_LONG │
├───────────────────────────┼──────────────────────────────────┤
│FLOAT │ Datatype FLOAT │
├───────────────────────────┼──────────────────────────────────┤
│DOUBLE │ Datatype DOUBLE │
├───────────────────────────┼──────────────────────────────────┤
│LONG_DOUBLE │ Datatype LONG_DOUBLE │
├───────────────────────────┼──────────────────────────────────┤
│C_BOOL │ Datatype C_BOOL │
├───────────────────────────┼──────────────────────────────────┤
│INT8_T │ Datatype INT8_T │
├───────────────────────────┼──────────────────────────────────┤
│INT16_T │ Datatype INT16_T │
├───────────────────────────┼──────────────────────────────────┤
│INT32_T │ Datatype INT32_T │
├───────────────────────────┼──────────────────────────────────┤
│INT64_T │ Datatype INT64_T │
├───────────────────────────┼──────────────────────────────────┤
│UINT8_T │ Datatype UINT8_T │
├───────────────────────────┼──────────────────────────────────┤
│UINT16_T │ Datatype UINT16_T │
├───────────────────────────┼──────────────────────────────────┤
│UINT32_T │ Datatype UINT32_T │
├───────────────────────────┼──────────────────────────────────┤
│UINT64_T │ Datatype UINT64_T │
├───────────────────────────┼──────────────────────────────────┤
│C_COMPLEX │ Datatype C_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│C_FLOAT_COMPLEX │ Datatype C_FLOAT_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│C_DOUBLE_COMPLEX │ Datatype C_DOUBLE_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│C_LONG_DOUBLE_COMPLEX │ Datatype C_LONG_DOUBLE_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│CXX_BOOL │ Datatype CXX_BOOL │
├───────────────────────────┼──────────────────────────────────┤
│CXX_FLOAT_COMPLEX │ Datatype CXX_FLOAT_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│CXX_DOUBLE_COMPLEX │ Datatype CXX_DOUBLE_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│CXX_LONG_DOUBLE_COMPLEX │ Datatype CXX_LONG_DOUBLE_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│SHORT_INT │ Datatype SHORT_INT │
├───────────────────────────┼──────────────────────────────────┤
│INT_INT │ Datatype INT_INT │
├───────────────────────────┼──────────────────────────────────┤
│TWOINT │ Datatype TWOINT │
├───────────────────────────┼──────────────────────────────────┤
│LONG_INT │ Datatype LONG_INT │
├───────────────────────────┼──────────────────────────────────┤
│FLOAT_INT │ Datatype FLOAT_INT │
├───────────────────────────┼──────────────────────────────────┤
│DOUBLE_INT │ Datatype DOUBLE_INT │
├───────────────────────────┼──────────────────────────────────┤
│LONG_DOUBLE_INT │ Datatype LONG_DOUBLE_INT │
├───────────────────────────┼──────────────────────────────────┤
│CHARACTER │ Datatype CHARACTER │
├───────────────────────────┼──────────────────────────────────┤
│LOGICAL │ Datatype LOGICAL │
├───────────────────────────┼──────────────────────────────────┤
│INTEGER │ Datatype INTEGER │
├───────────────────────────┼──────────────────────────────────┤
│REAL │ Datatype REAL │
├───────────────────────────┼──────────────────────────────────┤
│DOUBLE_PRECISION │ Datatype DOUBLE_PRECISION │
├───────────────────────────┼──────────────────────────────────┤
│COMPLEX │ Datatype COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│DOUBLE_COMPLEX │ Datatype DOUBLE_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│LOGICAL1 │ Datatype LOGICAL1 │
├───────────────────────────┼──────────────────────────────────┤
│LOGICAL2 │ Datatype LOGICAL2 │
├───────────────────────────┼──────────────────────────────────┤
│LOGICAL4 │ Datatype LOGICAL4 │
├───────────────────────────┼──────────────────────────────────┤
│LOGICAL8 │ Datatype LOGICAL8 │
├───────────────────────────┼──────────────────────────────────┤
│INTEGER1 │ Datatype INTEGER1 │
├───────────────────────────┼──────────────────────────────────┤
│INTEGER2 │ Datatype INTEGER2 │
├───────────────────────────┼──────────────────────────────────┤
│INTEGER4 │ Datatype INTEGER4 │
├───────────────────────────┼──────────────────────────────────┤
│INTEGER8 │ Datatype INTEGER8 │
├───────────────────────────┼──────────────────────────────────┤
│INTEGER16 │ Datatype INTEGER16 │
├───────────────────────────┼──────────────────────────────────┤
│REAL2 │ Datatype REAL2 │
├───────────────────────────┼──────────────────────────────────┤
│REAL4 │ Datatype REAL4 │
├───────────────────────────┼──────────────────────────────────┤
│REAL8 │ Datatype REAL8 │
├───────────────────────────┼──────────────────────────────────┤
│REAL16 │ Datatype REAL16 │
├───────────────────────────┼──────────────────────────────────┤
│COMPLEX4 │ Datatype COMPLEX4 │
├───────────────────────────┼──────────────────────────────────┤
│COMPLEX8 │ Datatype COMPLEX8 │
├───────────────────────────┼──────────────────────────────────┤
│COMPLEX16 │ Datatype COMPLEX16 │
├───────────────────────────┼──────────────────────────────────┤
│COMPLEX32 │ Datatype COMPLEX32 │
├───────────────────────────┼──────────────────────────────────┤
│UNSIGNED_INT │ Datatype UNSIGNED_INT │
├───────────────────────────┼──────────────────────────────────┤
│SIGNED_SHORT │ Datatype SIGNED_SHORT │
├───────────────────────────┼──────────────────────────────────┤
│SIGNED_INT │ Datatype SIGNED_INT │
├───────────────────────────┼──────────────────────────────────┤
│SIGNED_LONG │ Datatype SIGNED_LONG │
├───────────────────────────┼──────────────────────────────────┤
│SIGNED_LONG_LONG │ Datatype SIGNED_LONG_LONG │
├───────────────────────────┼──────────────────────────────────┤
│BOOL │ Datatype BOOL │
├───────────────────────────┼──────────────────────────────────┤
│SINT8_T │ Datatype SINT8_T │
├───────────────────────────┼──────────────────────────────────┤
│SINT16_T │ Datatype SINT16_T │
├───────────────────────────┼──────────────────────────────────┤
│SINT32_T │ Datatype SINT32_T │
├───────────────────────────┼──────────────────────────────────┤
│SINT64_T │ Datatype SINT64_T │
├───────────────────────────┼──────────────────────────────────┤
│F_BOOL │ Datatype F_BOOL │
├───────────────────────────┼──────────────────────────────────┤
│F_INT │ Datatype F_INT │
├───────────────────────────┼──────────────────────────────────┤
│F_FLOAT │ Datatype F_FLOAT │
├───────────────────────────┼──────────────────────────────────┤
│F_DOUBLE │ Datatype F_DOUBLE │
├───────────────────────────┼──────────────────────────────────┤
│F_COMPLEX │ Datatype F_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│F_FLOAT_COMPLEX │ Datatype F_FLOAT_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│F_DOUBLE_COMPLEX │ Datatype F_DOUBLE_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│REQUEST_NULL │ Request REQUEST_NULL │
├───────────────────────────┼──────────────────────────────────┤
│MESSAGE_NULL │ Message MESSAGE_NULL │
├───────────────────────────┼──────────────────────────────────┤
│MESSAGE_NO_PROC │ Message MESSAGE_NO_PROC │
├───────────────────────────┼──────────────────────────────────┤
│OP_NULL │ Op OP_NULL │
├───────────────────────────┼──────────────────────────────────┤
│MAX │ Op MAX │
├───────────────────────────┼──────────────────────────────────┤
│MIN │ Op MIN │
├───────────────────────────┼──────────────────────────────────┤
│SUM │ Op SUM │
├───────────────────────────┼──────────────────────────────────┤
│PROD │ Op PROD │
├───────────────────────────┼──────────────────────────────────┤
│LAND │ Op LAND │
├───────────────────────────┼──────────────────────────────────┤
│BAND │ Op BAND │
├───────────────────────────┼──────────────────────────────────┤
│LOR │ Op LOR │
├───────────────────────────┼──────────────────────────────────┤
│BOR │ Op BOR │
├───────────────────────────┼──────────────────────────────────┤
│LXOR │ Op LXOR │
├───────────────────────────┼──────────────────────────────────┤
│BXOR │ Op BXOR │
├───────────────────────────┼──────────────────────────────────┤
│MAXLOC │ Op MAXLOC │
├───────────────────────────┼──────────────────────────────────┤
│MINLOC │ Op MINLOC │
├───────────────────────────┼──────────────────────────────────┤
│REPLACE │ Op REPLACE │
├───────────────────────────┼──────────────────────────────────┤
│NO_OP │ Op NO_OP │
├───────────────────────────┼──────────────────────────────────┤
│GROUP_NULL │ Group GROUP_NULL │
├───────────────────────────┼──────────────────────────────────┤
│GROUP_EMPTY │ Group GROUP_EMPTY │
├───────────────────────────┼──────────────────────────────────┤
│INFO_NULL │ Info INFO_NULL │
├───────────────────────────┼──────────────────────────────────┤
│INFO_ENV │ Info INFO_ENV │
├───────────────────────────┼──────────────────────────────────┤
│ERRHANDLER_NULL │ Errhandler ERRHANDLER_NULL │
├───────────────────────────┼──────────────────────────────────┤
│ERRORS_RETURN │ Errhandler ERRORS_RETURN │
├───────────────────────────┼──────────────────────────────────┤
│ERRORS_ARE_FATAL │ Errhandler ERRORS_ARE_FATAL │
├───────────────────────────┼──────────────────────────────────┤
│COMM_NULL │ Comm COMM_NULL │
├───────────────────────────┼──────────────────────────────────┤
│COMM_SELF │ Intracomm COMM_SELF │
├───────────────────────────┼──────────────────────────────────┤
│COMM_WORLD │ Intracomm COMM_WORLD │
├───────────────────────────┼──────────────────────────────────┤
│WIN_NULL │ Win WIN_NULL │
├───────────────────────────┼──────────────────────────────────┤
│FILE_NULL │ File FILE_NULL │
├───────────────────────────┼──────────────────────────────────┤
│pickle │ Pickle pickle │
└───────────────────────────┴──────────────────────────────────┘
MPI4PY.FUTURES
Added in version 3.0.0.
This package provides a high-level interface for asynchronously executing callables on a
pool of worker processes using MPI for inter-process communication.
concurrent.futures
The mpi4py.futures package is based on concurrent.futures from the Python standard
library. More precisely, mpi4py.futures provides the MPIPoolExecutor class as a concrete
implementation of the abstract class Executor. The submit() interface schedules a
callable to be executed asynchronously and returns a Future object representing the
execution of the callable. Future instances can be queried for the call result or
exception. Sets of Future instances can be passed to the wait() and as_completed()
functions.
NOTE:
The concurrent.futures package was introduced in Python 3.2. A backport targeting
Python 2.7 is available on PyPI. The mpi4py.futures package uses concurrent.futures if
available, either from the Python 3 standard library or the Python 2.7 backport if
installed. Otherwise, mpi4py.futures uses a bundled copy of core functionality
backported from Python 3.5 to work with Python 2.7.
SEE ALSO:
Module concurrent.futures
Documentation of the concurrent.futures standard module.
MPIPoolExecutor
The MPIPoolExecutor class uses a pool of MPI processes to execute calls asynchronously. By
performing computations in separate processes, it allows to side-step the global
interpreter lock but also means that only picklable objects can be executed and returned.
The __main__ module must be importable by worker processes, thus MPIPoolExecutor instances
may not work in the interactive interpreter.
MPIPoolExecutor takes advantage of the dynamic process management features introduced in
the MPI-2 standard. In particular, the MPI.Intracomm.Spawn method of MPI.COMM_SELF is used
in the master (or parent) process to spawn new worker (or child) processes running a
Python interpreter. The master process uses a separate thread (one for each
MPIPoolExecutor instance) to communicate back and forth with the workers. The worker
processes serve the execution of tasks in the main (and only) thread until they are
signaled for completion.
NOTE:
The worker processes must import the main script in order to unpickle any callable
defined in the __main__ module and submitted from the master process. Furthermore, the
callables may need access to other global variables. At the worker processes,
mpi4py.futures executes the main script code (using the runpy module) under the
__worker__ namespace to define the __main__ module. The __main__ and __worker__ modules
are added to sys.modules (both at the master and worker processes) to ensure proper
pickling and unpickling.
WARNING:
During the initial import phase at the workers, the main script cannot create and use
new MPIPoolExecutor instances. Otherwise, each worker would attempt to spawn a new pool
of workers, leading to infinite recursion. mpi4py.futures detects such recursive
attempts to spawn new workers and aborts the MPI execution environment. As the main
script code is run under the __worker__ namespace, the easiest way to avoid spawn
recursion is using the idiom if __name__ == '__main__': ... in the main script.
class mpi4py.futures.MPIPoolExecutor(max_workers=None, initializer=None, initargs=(),
**kwargs)
An Executor subclass that executes calls asynchronously using a pool of at most
max_workers processes. If max_workers is None or not given, its value is
determined from the MPI4PY_FUTURES_MAX_WORKERS environment variable if set, or the
MPI universe size if set, otherwise a single worker process is spawned. If
max_workers is lower than or equal to 0, then a ValueError will be raised.
initializer is an optional callable that is called at the start of each worker
process before executing any tasks; initargs is a tuple of arguments passed to the
initializer. If initializer raises an exception, all pending tasks and any attempt
to submit new tasks to the pool will raise a BrokenExecutor exception.
Other parameters:
• python_exe: Path to the Python interpreter executable used to spawn worker
processes, otherwise sys.executable is used.
• python_args: list or iterable with additional command line flags to pass to the
Python executable. Command line flags determined from inspection of sys.flags, ‐
sys.warnoptions and sys._xoptions in are passed unconditionally.
• mpi_info: dict or iterable yielding (key, value) pairs. These (key, value) pairs
are passed (through an MPI.Info object) to the MPI.Intracomm.Spawn call used to
spawn worker processes. This mechanism allows telling the MPI runtime system
where and how to start the processes. Check the documentation of the backend MPI
implementation about the set of keys it interprets and the corresponding format
for values.
• globals: dict or iterable yielding (name, value) pairs to initialize the main
module namespace in worker processes.
• main: If set to False, do not import the __main__ module in worker processes.
Setting main to False prevents worker processes from accessing definitions in the
parent __main__ namespace.
• path: list or iterable with paths to append to sys.path in worker processes to
extend the module search path.
• wdir: Path to set the current working directory in worker processes using ‐
os.chdir(). The initial working directory is set by the MPI implementation.
Quality MPI implementations should honor a wdir info key passed through mpi_info,
although such feature is not mandatory.
• env: dict or iterable yielding (name, value) pairs with environment variables to
update os.environ in worker processes. The initial environment is set by the MPI
implementation. MPI implementations may allow setting the initial environment
through mpi_info, however such feature is not required nor recommended by the MPI
standard.
submit(func, *args, **kwargs)
Schedule the callable, func, to be executed as func(*args, **kwargs) and
returns a Future object representing the execution of the callable.
executor = MPIPoolExecutor(max_workers=1)
future = executor.submit(pow, 321, 1234)
print(future.result())
map(func, *iterables, timeout=None, chunksize=1, **kwargs)
Equivalent to map(func, *iterables) except func is executed asynchronously
and several calls to func may be made concurrently, out-of-order, in
separate processes. The returned iterator raises a TimeoutError if ‐
__next__() is called and the result isn’t available after timeout seconds
from the original call to map(). timeout can be an int or a float. If
timeout is not specified or None, there is no limit to the wait time. If a
call raises an exception, then that exception will be raised when its value
is retrieved from the iterator. This method chops iterables into a number of
chunks which it submits to the pool as separate tasks. The (approximate)
size of these chunks can be specified by setting chunksize to a positive
integer. For very long iterables, using a large value for chunksize can
significantly improve performance compared to the default size of one. By
default, the returned iterator yields results in-order, waiting for
successive tasks to complete . This behavior can be changed by passing the
keyword argument unordered as True, then the result iterator will yield a
result as soon as any of the tasks complete.
executor = MPIPoolExecutor(max_workers=3)
for result in executor.map(pow, [2]*32, range(32)):
print(result)
starmap(func, iterable, timeout=None, chunksize=1, **kwargs)
Equivalent to itertools.starmap(func, iterable). Used instead of map() when
argument parameters are already grouped in tuples from a single iterable
(the data has been “pre-zipped”). map(func, *iterable) is equivalent to
starmap(func, zip(*iterable)).
executor = MPIPoolExecutor(max_workers=3)
iterable = ((2, n) for n in range(32))
for result in executor.starmap(pow, iterable):
print(result)
shutdown(wait=True, cancel_futures=False)
Signal the executor that it should free any resources that it is using when
the currently pending futures are done executing. Calls to submit() and
map() made after shutdown() will raise RuntimeError.
If wait is True then this method will not return until all the pending
futures are done executing and the resources associated with the executor
have been freed. If wait is False then this method will return immediately
and the resources associated with the executor will be freed when all
pending futures are done executing. Regardless of the value of wait, the
entire Python program will not exit until all pending futures are done
executing.
If cancel_futures is True, this method will cancel all pending futures that
the executor has not started running. Any futures that are completed or
running won’t be cancelled, regardless of the value of cancel_futures.
You can avoid having to call this method explicitly if you use the with
statement, which will shutdown the executor instance (waiting as if
shutdown() were called with wait set to True).
import time
with MPIPoolExecutor(max_workers=1) as executor:
future = executor.submit(time.sleep, 2)
assert future.done()
bootup(wait=True)
Signal the executor that it should allocate eagerly any required resources
(in particular, MPI worker processes). If wait is True, then bootup() will
not return until the executor resources are ready to process submissions.
Resources are automatically allocated in the first call to submit(), thus
calling bootup() explicitly is seldom needed.
MPI4PY_FUTURES_MAX_WORKERS
If the max_workers parameter to MPIPoolExecutor is None or not given, the
MPI4PY_FUTURES_MAX_WORKERS environment variable provides fallback value for the
maximum number of MPI worker processes to spawn.
NOTE:
As the master process uses a separate thread to perform MPI communication with the
workers, the backend MPI implementation should provide support for MPI.THREAD_MULTIPLE.
However, some popular MPI implementations do not support yet concurrent MPI calls from
multiple threads. Additionally, users may decide to initialize MPI with a lower level
of thread support. If the level of thread support in the backend MPI is less than
MPI.THREAD_MULTIPLE, mpi4py.futures will use a global lock to serialize MPI calls. If
the level of thread support is less than MPI.THREAD_SERIALIZED, mpi4py.futures will
emit a RuntimeWarning.
WARNING:
If the level of thread support in the backend MPI is less than MPI.THREAD_SERIALIZED
(i.e, it is either MPI.THREAD_SINGLE or MPI.THREAD_FUNNELED), in theory mpi4py.futures
cannot be used. Rather than raising an exception, mpi4py.futures emits a warning and
takes a “cross-fingers” attitude to continue execution in the hope that serializing MPI
calls with a global lock will actually work.
MPICommExecutor
Legacy MPI-1 implementations (as well as some vendor MPI-2 implementations) do not support
the dynamic process management features introduced in the MPI-2 standard. Additionally,
job schedulers and batch systems in supercomputing facilities may pose additional
complications to applications using the MPI_Comm_spawn() routine.
With these issues in mind, mpi4py.futures supports an additonal, more traditional,
SPMD-like usage pattern requiring MPI-1 calls only. Python applications are started the
usual way, e.g., using the mpiexec command. Python code should make a collective call to
the MPICommExecutor context manager to partition the set of MPI processes within a MPI
communicator in one master processes and many workers processes. The master process gets
access to an MPIPoolExecutor instance to submit tasks. Meanwhile, the worker process
follow a different execution path and team-up to execute the tasks submitted from the
master.
Besides alleviating the lack of dynamic process managment features in legacy MPI-1 or
partial MPI-2 implementations, the MPICommExecutor context manager may be useful in
classic MPI-based Python applications willing to take advantage of the simple, task-based,
master/worker approach available in the mpi4py.futures package.
class mpi4py.futures.MPICommExecutor(comm=None, root=0)
Context manager for MPIPoolExecutor. This context manager splits a MPI
(intra)communicator comm (defaults to MPI.COMM_WORLD if not provided or None) in
two disjoint sets: a single master process (with rank root in comm) and the
remaining worker processes. These sets are then connected through an
intercommunicator. The target of the with statement is assigned either an
MPIPoolExecutor instance (at the master) or None (at the workers).
from mpi4py import MPI
from mpi4py.futures import MPICommExecutor
with MPICommExecutor(MPI.COMM_WORLD, root=0) as executor:
if executor is not None:
future = executor.submit(abs, -42)
assert future.result() == 42
answer = set(executor.map(abs, [-42, 42]))
assert answer == {42}
WARNING:
If MPICommExecutor is passed a communicator of size one (e.g., MPI.COMM_SELF), then the
executor instace assigned to the target of the with statement will execute all
submitted tasks in a single worker thread, thus ensuring that task execution still
progress asynchronously. However, the GIL will prevent the main and worker threads from
running concurrently in multicore processors. Moreover, the thread context switching
may harm noticeably the performance of CPU-bound tasks. In case of I/O-bound tasks, the
GIL is not usually an issue, however, as a single worker thread is used, it progress
one task at a time. We advice against using MPICommExecutor with communicators of size
one and suggest refactoring your code to use instead a ThreadPoolExecutor.
Command line
Recalling the issues related to the lack of support for dynamic process managment features
in MPI implementations, mpi4py.futures supports an alternative usage pattern where Python
code (either from scripts, modules, or zip files) is run under command line control of the
mpi4py.futures package by passing -m mpi4py.futures to the python executable. The
mpi4py.futures invocation should be passed a pyfile path to a script (or a
zipfile/directory containing a __main__.py file). Additionally, mpi4py.futures accepts -m
mod to execute a module named mod, -c cmd to execute a command string cmd, or even - to
read commands from standard input (sys.stdin). Summarizing, mpi4py.futures can be invoked
in the following ways:
• $ mpiexec -n numprocs python -m mpi4py.futures pyfile [arg] ...
• $ mpiexec -n numprocs python -m mpi4py.futures -m mod [arg] ...
• $ mpiexec -n numprocs python -m mpi4py.futures -c cmd [arg] ...
• $ mpiexec -n numprocs python -m mpi4py.futures - [arg] ...
Before starting the main script execution, mpi4py.futures splits MPI.COMM_WORLD in one
master (the process with rank 0 in MPI.COMM_WORLD) and numprocs - 1 workers and connects
them through an MPI intercommunicator. Afterwards, the master process proceeds with the
execution of the user script code, which eventually creates MPIPoolExecutor instances to
submit tasks. Meanwhile, the worker processes follow a different execution path to serve
the master. Upon successful termination of the main script at the master, the entire MPI
execution environment exists gracefully. In case of any unhandled exception in the main
script, the master process calls MPI.COMM_WORLD.Abort(1) to prevent deadlocks and force
termination of entire MPI execution environment.
WARNING:
Running scripts under command line control of mpi4py.futures is quite similar to
executing a single-process application that spawn additional workers as required.
However, there is a very important difference users should be aware of. All
MPIPoolExecutor instances created at the master will share the pool of workers. Tasks
submitted at the master from many different executors will be scheduled for execution
in random order as soon as a worker is idle. Any executor can easily starve all the
workers (e.g., by calling MPIPoolExecutor.map() with long iterables). If that ever
happens, submissions from other executors will not be serviced until free workers are
available.
SEE ALSO:
Command line
Documentation on Python command line interface.
Examples
The following julia.py script computes the Julia set and dumps an image to disk in binary
PGM format. The code starts by importing MPIPoolExecutor from the mpi4py.futures package.
Next, some global constants and functions implement the computation of the Julia set. The
computations are protected with the standard if __name__ == '__main__':... idiom. The
image is computed by whole scanlines submitting all these tasks at once using the map
method. The result iterator yields scanlines in-order as the tasks complete. Finally, each
scanline is dumped to disk.
julia.py
from mpi4py.futures import MPIPoolExecutor
x0, x1, w = -2.0, +2.0, 640*2
y0, y1, h = -1.5, +1.5, 480*2
dx = (x1 - x0) / w
dy = (y1 - y0) / h
c = complex(0, 0.65)
def julia(x, y):
z = complex(x, y)
n = 255
while abs(z) < 3 and n > 1:
z = z**2 + c
n -= 1
return n
def julia_line(k):
line = bytearray(w)
y = y1 - k * dy
for j in range(w):
x = x0 + j * dx
line[j] = julia(x, y)
return line
if __name__ == '__main__':
with MPIPoolExecutor() as executor:
image = executor.map(julia_line, range(h))
with open('julia.pgm', 'wb') as f:
f.write(b'P5 %d %d %d\n' % (w, h, 255))
for line in image:
f.write(line)
The recommended way to execute the script is by using the mpiexec command specifying one
MPI process (master) and (optional but recommended) the desired MPI universe size, which
determines the number of additional dynamically spawned processes (workers). The MPI
universe size is provided either by a batch system or set by the user via command-line
arguments to mpiexec or environment variables. Below we provide examples for MPICH and
Open MPI implementations [1]. In all of these examples, the mpiexec command launches a
single master process running the Python interpreter and executing the main script. When
required, mpi4py.futures spawns the pool of 16 worker processes. The master submits tasks
to the workers and waits for the results. The workers receive incoming tasks, execute
them, and send back the results to the master.
When using MPICH implementation or its derivatives based on the Hydra process manager,
users can set the MPI universe size via the -usize argument to mpiexec:
$ mpiexec -n 1 -usize 17 python julia.py
or, alternatively, by setting the MPIEXEC_UNIVERSE_SIZE environment variable:
$ MPIEXEC_UNIVERSE_SIZE=17 mpiexec -n 1 python julia.py
In the Open MPI implementation, the MPI universe size can be set via the -host argument to
mpiexec:
$ mpiexec -n 1 -host <hostname>:17 python julia.py
Another way to specify the number of workers is to use the mpi4py.futures-specific
environment variable MPI4PY_FUTURES_MAX_WORKERS:
$ MPI4PY_FUTURES_MAX_WORKERS=16 mpiexec -n 1 python julia.py
Note that in this case, the MPI universe size is ignored.
Alternatively, users may decide to execute the script in a more traditional way, that is,
all the MPI processes are started at once. The user script is run under command-line
control of mpi4py.futures passing the -m flag to the python executable:
$ mpiexec -n 17 python -m mpi4py.futures julia.py
As explained previously, the 17 processes are partitioned in one master and 16 workers.
The master process executes the main script while the workers execute the tasks submitted
by the master.
[1] When using an MPI implementation other than MPICH or Open MPI, please check the
documentation of the implementation and/or batch system for the ways to specify the
desired MPI universe size.
GIL See global interpreter lock.
MPI4PY.UTIL
Added in version 3.1.0.
The mpi4py.util package collects miscellaneous utilities within the intersection of Python
and MPI.
mpi4py.util.pkl5
Added in version 3.1.0.
pickle protocol 5 (see PEP 574) introduced support for out-of-band buffers, allowing for
more efficient handling of certain object types with large memory footprints.
MPI for Python uses the traditional in-band handling of buffers. This approach is
appropriate for communicating non-buffer Python objects, or buffer-like objects with small
memory footprints. For point-to-point communication, in-band buffer handling allows for
the communication of a pickled stream with a single MPI message, at the expense of
additional CPU and memory overhead in the pickling and unpickling steps.
The mpi4py.util.pkl5 module provides communicator wrapper classes reimplementing
pickle-based point-to-point communication methods using pickle protocol 5. Handling
out-of-band buffers necessarily involve multiple MPI messages, thus increasing latency and
hurting performance in case of small size data. However, in case of large size data, the
zero-copy savings of out-of-band buffer handling more than offset the extra latency costs.
Additionally, these wrapper methods overcome the infamous 2 GiB message count limit (MPI-1
to MPI-3).
NOTE:
Support for pickle protocol 5 is available in the pickle module within the Python
standard library since Python 3.8. Previous Python 3 releases can use the pickle5
backport, which is available on PyPI and can be installed with:
python -m pip install pickle5
class mpi4py.util.pkl5.Request(request=None)
Request.
Custom request class for nonblocking communications.
NOTE:
Request is not a subclass of mpi4py.MPI.Request
Parameters
request (Iterable[MPI.Request])
Return type
Request
Free() Free a communication request.
Return type
None
cancel()
Cancel a communication request.
Return type
None
get_status(status=None)
Non-destructive test for the completion of a request.
Parameters
status (Optional[Status])
Return type
bool
test(status=None)
Test for the completion of a request.
Parameters
status (Optional[Status])
Return type
Tuple[bool, Optional[Any]]
wait(status=None)
Wait for a request to complete.
Parameters
status (Optional[Status])
Return type
Any
classmethod testall(requests, statuses=None)
Test for the completion of all requests.
Classmethod
classmethod waitall(requests, statuses=None)
Wait for all requests to complete.
Classmethod
class mpi4py.util.pkl5.Message(message=None)
Message.
Custom message class for matching probes.
NOTE:
Message is not a subclass of mpi4py.MPI.Message
Parameters
message (Iterable[MPI.Message])
Return type
Message
recv(status=None)
Blocking receive of matched message.
Parameters
status (Optional[Status])
Return type
Any
irecv()
Nonblocking receive of matched message.
Return type
Request
classmethod probe(comm, source=ANY_SOURCE, tag=ANY_TAG, status=None)
Blocking test for a matched message.
Classmethod
classmethod iprobe(comm, source=ANY_SOURCE, tag=ANY_TAG, status=None)
Nonblocking test for a matched message.
Classmethod
class mpi4py.util.pkl5.Comm
Communicator.
Base communicator wrapper class.
send(obj, dest, tag=0)
Blocking send in standard mode.
Parameters
• obj (Any)
• dest (int)
• tag (int)
Return type
None
bsend(obj, dest, tag=0)
Blocking send in buffered mode.
Parameters
• obj (Any)
• dest (int)
• tag (int)
Return type
None
ssend(obj, dest, tag=0)
Blocking send in synchronous mode.
Parameters
• obj (Any)
• dest (int)
• tag (int)
Return type
None
isend(obj, dest, tag=0)
Nonblocking send in standard mode.
Parameters
• obj (Any)
• dest (int)
• tag (int)
Return type
Request
ibsend(obj, dest, tag=0)
Nonblocking send in buffered mode.
Parameters
• obj (Any)
• dest (int)
• tag (int)
Return type
Request
issend(obj, dest, tag=0)
Nonblocking send in synchronous mode.
Parameters
• obj (Any)
• dest (int)
• tag (int)
Return type
Request
recv(buf=None, source=ANY_SOURCE, tag=ANY_TAG, status=None)
Blocking receive.
Parameters
• buf (Optional[Buffer])
• source (int)
• tag (int)
• status (Optional[Status])
Return type
Any
irecv(buf=None, source=ANY_SOURCE, tag=ANY_TAG)
Nonblocking receive.
WARNING:
This method cannot be supported reliably and raises RuntimeError.
Parameters
• buf (Optional[Buffer])
• source (int)
• tag (int)
Return type
Request
sendrecv(sendobj, dest, sendtag=0, recvbuf=None, source=ANY_SOURCE,
recvtag=ANY_TAG, status=None)
Send and receive.
Parameters
• sendobj (Any)
• dest (int)
• sendtag (int)
• recvbuf (Optional[Buffer])
• source (int)
• recvtag (int)
• status (Optional[Status])
Return type
Any
mprobe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
Blocking test for a matched message.
Parameters
• source (int)
• tag (int)
• status (Optional[Status])
Return type
Message
improbe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
Nonblocking test for a matched message.
Parameters
• source (int)
• tag (int)
• status (Optional[Status])
Return type
Optional[Message]
bcast(obj, root=0)
Broadcast.
Parameters
• obj (Any)
• root (int)
Return type
Any
class mpi4py.util.pkl5.Intracomm
Intracommunicator.
Intracommunicator wrapper class.
class mpi4py.util.pkl5.Intercomm
Intercommunicator.
Intercommunicator wrapper class.
Examples
test-pkl5-1.py
import numpy as np
from mpi4py import MPI
from mpi4py.util import pkl5
comm = pkl5.Intracomm(MPI.COMM_WORLD) # comm wrapper
size = comm.Get_size()
rank = comm.Get_rank()
dst = (rank + 1) % size
src = (rank - 1) % size
sobj = np.full(1024**3, rank, dtype='i4') # > 4 GiB
sreq = comm.isend(sobj, dst, tag=42)
robj = comm.recv (None, src, tag=42)
sreq.Free()
assert np.min(robj) == src
assert np.max(robj) == src
test-pkl5-2.py
import numpy as np
from mpi4py import MPI
from mpi4py.util import pkl5
comm = pkl5.Intracomm(MPI.COMM_WORLD) # comm wrapper
size = comm.Get_size()
rank = comm.Get_rank()
dst = (rank + 1) % size
src = (rank - 1) % size
sobj = np.full(1024**3, rank, dtype='i4') # > 4 GiB
sreq = comm.isend(sobj, dst, tag=42)
status = MPI.Status()
rmsg = comm.mprobe(status=status)
assert status.Get_source() == src
assert status.Get_tag() == 42
rreq = rmsg.irecv()
robj = rreq.wait()
sreq.Free()
assert np.max(robj) == src
assert np.min(robj) == src
mpi4py.util.dtlib
Added in version 3.1.0.
The mpi4py.util.dtlib module provides converter routines between NumPy and MPI datatypes.
mpi4py.util.dtlib.from_numpy_dtype(dtype)
Convert NumPy datatype to MPI datatype.
Parameters
dtype (numpy.typing.DTypeLike) – NumPy dtype-like object.
Return type
Datatype
mpi4py.util.dtlib.to_numpy_dtype(datatype)
Convert MPI datatype to NumPy datatype.
Parameters
datatype (Datatype) – MPI datatype.
Return type
numpy.dtype
MPI4PY.RUN
Added in version 3.0.0.
At import time, mpi4py initializes the MPI execution environment calling MPI_Init_thread()
and installs an exit hook to automatically call MPI_Finalize() just before the Python
process terminates. Additionally, mpi4py overrides the default ERRORS_ARE_FATAL error
handler in favor of ERRORS_RETURN, which allows translating MPI errors in Python
exceptions. These departures from standard MPI behavior may be controversial, but are
quite convenient within the highly dynamic Python programming environment. Third-party
code using mpi4py can just from mpi4py import MPI and perform MPI calls without the
tedious initialization/finalization handling. MPI errors, once translated automatically
to Python exceptions, can be dealt with the common try…except…finally clauses; unhandled
MPI exceptions will print a traceback which helps in locating problems in source code.
Unfortunately, the interplay of automatic MPI finalization and unhandled exceptions may
lead to deadlocks. In unattended runs, these deadlocks will drain the battery of your
laptop, or burn precious allocation hours in your supercomputing facility.
Consider the following snippet of Python code. Assume this code is stored in a standard
Python script file and run with mpiexec in two or more processes.
from mpi4py import MPI
assert MPI.COMM_WORLD.Get_size() > 1
rank = MPI.COMM_WORLD.Get_rank()
if rank == 0:
1/0
MPI.COMM_WORLD.send(None, dest=1, tag=42)
elif rank == 1:
MPI.COMM_WORLD.recv(source=0, tag=42)
Process 0 raises ZeroDivisionError exception before performing a send call to process 1.
As the exception is not handled, the Python interpreter running in process 0 will proceed
to exit with non-zero status. However, as mpi4py installed a finalizer hook to call
MPI_Finalize() before exit, process 0 will block waiting for other processes to also enter
the MPI_Finalize() call. Meanwhile, process 1 will block waiting for a message to arrive
from process 0, thus never reaching to MPI_Finalize(). The whole MPI execution environment
is irremediably in a deadlock state.
To alleviate this issue, mpi4py offers a simple, alternative command line execution
mechanism based on using the -m flag and implemented with the runpy module. To use this
features, Python code should be run passing -m mpi4py in the command line invoking the
Python interpreter. In case of unhandled exceptions, the finalizer hook will call
MPI_Abort() on the MPI_COMM_WORLD communicator, thus effectively aborting the MPI
execution environment.
WARNING:
When a process is forced to abort, resources (e.g. open files) are not cleaned-up and
any registered finalizers (either with the atexit module, the Python C/API function ‐
Py_AtExit(), or even the C standard library function atexit()) will not be executed.
Thus, aborting execution is an extremely impolite way of ensuring process termination.
However, MPI provides no other mechanism to recover from a deadlock state.
Interface options
The use of -m mpi4py to execute Python code on the command line resembles that of the
Python interpreter.
• mpiexec -n numprocs python -m mpi4py pyfile [arg] ...
• mpiexec -n numprocs python -m mpi4py -m mod [arg] ...
• mpiexec -n numprocs python -m mpi4py -c cmd [arg] ...
• mpiexec -n numprocs python -m mpi4py - [arg] ...
<pyfile>
Execute the Python code contained in pyfile, which must be a filesystem path
referring to either a Python file, a directory containing a __main__.py file, or a
zipfile containing a __main__.py file.
-m <mod>
Search sys.path for the named module mod and execute its contents.
-c <cmd>
Execute the Python code in the cmd string command.
- Read commands from standard input (sys.stdin).
SEE ALSO:
Command line
Documentation on Python command line interface.
REFERENCE
┌───────────┬────────────────────────────┐
│mpi4py.MPI │ Message Passing Interface. │
└───────────┴────────────────────────────┘
mpi4py.MPI
Message Passing Interface.
Classes
┌─────────────────────────────────┬──────────────────────────────────┐
│Cartcomm([comm]) │ Cartesian topology │
│ │ intracommunicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Comm([comm]) │ Communicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Datatype([datatype]) │ Datatype object │
├─────────────────────────────────┼──────────────────────────────────┤
│Distgraphcomm([comm]) │ Distributed graph topology │
│ │ intracommunicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Errhandler([errhandler]) │ Error handler │
├─────────────────────────────────┼──────────────────────────────────┤
│File([file]) │ File handle │
├─────────────────────────────────┼──────────────────────────────────┤
│Graphcomm([comm]) │ General graph topology │
│ │ intracommunicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Grequest([request]) │ Generalized request handle │
├─────────────────────────────────┼──────────────────────────────────┤
│Group([group]) │ Group of processes │
├─────────────────────────────────┼──────────────────────────────────┤
│Info([info]) │ Info object │
├─────────────────────────────────┼──────────────────────────────────┤
│Intercomm([comm]) │ Intercommunicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Intracomm([comm]) │ Intracommunicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Message([message]) │ Matched message handle │
├─────────────────────────────────┼──────────────────────────────────┤
│Op([op]) │ Operation object │
├─────────────────────────────────┼──────────────────────────────────┤
│Pickle([dumps, loads, protocol]) │ Pickle/unpickle Python objects │
├─────────────────────────────────┼──────────────────────────────────┤
│Prequest([request]) │ Persistent request handle │
├─────────────────────────────────┼──────────────────────────────────┤
│Request([request]) │ Request handle │
├─────────────────────────────────┼──────────────────────────────────┤
│Status([status]) │ Status object │
├─────────────────────────────────┼──────────────────────────────────┤
│Topocomm([comm]) │ Topology intracommunicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Win([win]) │ Window handle │
├─────────────────────────────────┼──────────────────────────────────┤
│memory(buf) │ Memory buffer │
└─────────────────────────────────┴──────────────────────────────────┘
mpi4py.MPI.Cartcomm
class mpi4py.MPI.Cartcomm(comm=None)
Bases: Topocomm
Cartesian topology intracommunicator
Parameters
comm (Optional[Cartcomm])
Return type
Cartcomm
static __new__(cls, comm=None)
Parameters
comm (Optional[Cartcomm])
Return type
Cartcomm
Methods Summary
┌───────────────────────┬──────────────────────────────────┐
│Get_cart_rank(coords) │ Translate logical coordinates to │
│ │ ranks │
├───────────────────────┼──────────────────────────────────┤
│Get_coords(rank) │ Translate ranks to logical │
│ │ coordinates │
├───────────────────────┼──────────────────────────────────┤
│Get_dim() │ Return number of dimensions │
├───────────────────────┼──────────────────────────────────┤
│Get_topo() │ Return information on the │
│ │ cartesian topology │
├───────────────────────┼──────────────────────────────────┤
│Shift(direction, disp) │ Return a tuple (source, dest) of │
│ │ process ranks for data shifting │
│ │ with Comm.Sendrecv() │
├───────────────────────┼──────────────────────────────────┤
│Sub(remain_dims) │ Return cartesian communicators │
│ │ that form lower-dimensional │
│ │ subgrids │
└───────────────────────┴──────────────────────────────────┘
Attributes Summary
┌────────┬──────────────────────┐
│coords │ coordinates │
├────────┼──────────────────────┤
│dim │ number of dimensions │
├────────┼──────────────────────┤
│dims │ dimensions │
├────────┼──────────────────────┤
│ndim │ number of dimensions │
├────────┼──────────────────────┤
│periods │ periodicity │
├────────┼──────────────────────┤
│topo │ topology information │
└────────┴──────────────────────┘
Methods Documentation
Get_cart_rank(coords)
Translate logical coordinates to ranks
Parameters
coords (Sequence[int])
Return type
int
Get_coords(rank)
Translate ranks to logical coordinates
Parameters
rank (int)
Return type
List[int]
Get_dim()
Return number of dimensions
Return type
int
Get_topo()
Return information on the cartesian topology
Return type
Tuple[List[int], List[int], List[int]]
Shift(direction, disp)
Return a tuple (source, dest) of process ranks for data shifting with
Comm.Sendrecv()
Parameters
• direction (int)
• disp (int)
Return type
Tuple[int, int]
Sub(remain_dims)
Return cartesian communicators that form lower-dimensional subgrids
Parameters
remain_dims (Sequence[bool])
Return type
Cartcomm
Attributes Documentation
coords coordinates
dim number of dimensions
dims dimensions
ndim number of dimensions
periods
periodicity
topo topology information
mpi4py.MPI.Comm
class mpi4py.MPI.Comm(comm=None)
Bases: object
Communicator
Parameters
comm (Optional[Comm])
Return type
Comm
static __new__(cls, comm=None)
Parameters
comm (Optional[Comm])
Return type
Comm
Methods Summary
┌─────────────────────────────────┬──────────────────────────────────┐
│Abort([errorcode]) │ Terminate MPI execution │
│ │ environment │
├─────────────────────────────────┼──────────────────────────────────┤
│Allgather(sendbuf, recvbuf) │ Gather to All, gather data from │
│ │ all processes and distribute it │
│ │ to all other processes in a │
│ │ group │
├─────────────────────────────────┼──────────────────────────────────┤
│Allgatherv(sendbuf, recvbuf) │ Gather to All Vector, gather │
│ │ data from all processes and │
│ │ distribute it to all other │
│ │ processes in a group providing │
│ │ different amount of data and │
│ │ displacements │
├─────────────────────────────────┼──────────────────────────────────┤
│Allreduce(sendbuf, recvbuf[, │ Reduce to All │
│op]) │ │
├─────────────────────────────────┼──────────────────────────────────┤
│Alltoall(sendbuf, recvbuf) │ All to All Scatter/Gather, send │
│ │ data from all to all processes │
│ │ in a group │
├─────────────────────────────────┼──────────────────────────────────┤
│Alltoallv(sendbuf, recvbuf) │ All to All Scatter/Gather │
│ │ Vector, send data from all to │
│ │ all processes in a group │
│ │ providing different amount of │
│ │ data and displacements │
├─────────────────────────────────┼──────────────────────────────────┤
│Alltoallw(sendbuf, recvbuf) │ Generalized All-to-All │
│ │ communication allowing different │
│ │ counts, displacements and │
│ │ datatypes for each partner │
├─────────────────────────────────┼──────────────────────────────────┤
│Barrier() │ Barrier synchronization │
├─────────────────────────────────┼──────────────────────────────────┤
│Bcast(buf[, root]) │ Broadcast a message from one │
│ │ process to all other processes │
│ │ in a group │
├─────────────────────────────────┼──────────────────────────────────┤
│Bsend(buf, dest[, tag]) │ Blocking send in buffered mode │
├─────────────────────────────────┼──────────────────────────────────┤
│Bsend_init(buf, dest[, tag]) │ Persistent request for a send in │
│ │ buffered mode │
├─────────────────────────────────┼──────────────────────────────────┤
│Call_errhandler(errorcode) │ Call the error handler installed │
│ │ on a communicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Clone() │ Clone an existing communicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Compare(comm1, comm2) │ Compare two communicators │
├─────────────────────────────────┼──────────────────────────────────┤
│Create(group) │ Create communicator from group │
├─────────────────────────────────┼──────────────────────────────────┤
│Create_group(group[, tag]) │ Create communicator from group │
├─────────────────────────────────┼──────────────────────────────────┤
│Create_keyval([copy_fn, │ Create a new attribute key for │
│delete_fn, nopython]) │ communicators │
├─────────────────────────────────┼──────────────────────────────────┤
│Delete_attr(keyval) │ Delete attribute value │
│ │ associated with a key │
├─────────────────────────────────┼──────────────────────────────────┤
│Disconnect() │ Disconnect from a communicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Dup([info]) │ Duplicate an existing │
│ │ communicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Dup_with_info(info) │ Duplicate an existing │
│ │ communicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Free() │ Free a communicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Free_keyval(keyval) │ Free an attribute key for │
│ │ communicators │
├─────────────────────────────────┼──────────────────────────────────┤
│Gather(sendbuf, recvbuf[, root]) │ Gather together values from a │
│ │ group of processes │
├─────────────────────────────────┼──────────────────────────────────┤
│Gatherv(sendbuf, recvbuf[, │ Gather Vector, gather data to │
│root]) │ one process from all other │
│ │ processes in a group providing │
│ │ different amount of data and │
│ │ displacements at the receiving │
│ │ sides │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_attr(keyval) │ Retrieve attribute value by key │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_errhandler() │ Get the error handler for a │
│ │ communicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_group() │ Access the group associated with │
│ │ a communicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_info() │ Return the hints for a │
│ │ communicator that are currently │
│ │ in use │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_name() │ Get the print name for this │
│ │ communicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_parent() │ Return the parent │
│ │ intercommunicator for this │
│ │ process │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_rank() │ Return the rank of this process │
│ │ in a communicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_size() │ Return the number of processes │
│ │ in a communicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_topology() │ Determine the type of topology │
│ │ (if any) associated with a │
│ │ communicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Iallgather(sendbuf, recvbuf) │ Nonblocking Gather to All │
├─────────────────────────────────┼──────────────────────────────────┤
│Iallgatherv(sendbuf, recvbuf) │ Nonblocking Gather to All Vector │
├─────────────────────────────────┼──────────────────────────────────┤
│Iallreduce(sendbuf, recvbuf[, │ Nonblocking Reduce to All │
│op]) │ │
├─────────────────────────────────┼──────────────────────────────────┤
│Ialltoall(sendbuf, recvbuf) │ Nonblocking All to All │
│ │ Scatter/Gather │
├─────────────────────────────────┼──────────────────────────────────┤
│Ialltoallv(sendbuf, recvbuf) │ Nonblocking All to All │
│ │ Scatter/Gather Vector │
├─────────────────────────────────┼──────────────────────────────────┤
│Ialltoallw(sendbuf, recvbuf) │ Nonblocking Generalized │
│ │ All-to-All │
├─────────────────────────────────┼──────────────────────────────────┤
│Ibarrier() │ Nonblocking Barrier │
├─────────────────────────────────┼──────────────────────────────────┤
│Ibcast(buf[, root]) │ Nonblocking Broadcast │
├─────────────────────────────────┼──────────────────────────────────┤
│Ibsend(buf, dest[, tag]) │ Nonblocking send in buffered │
│ │ mode │
├─────────────────────────────────┼──────────────────────────────────┤
│Idup() │ Nonblocking duplicate an │
│ │ existing communicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Igather(sendbuf, recvbuf[, │ Nonblocking Gather │
│root]) │ │
├─────────────────────────────────┼──────────────────────────────────┤
│Igatherv(sendbuf, recvbuf[, │ Nonblocking Gather Vector │
│root]) │ │
├─────────────────────────────────┼──────────────────────────────────┤
│Improbe([source, tag, status]) │ Nonblocking test for a matched │
│ │ message │
├─────────────────────────────────┼──────────────────────────────────┤
│Iprobe([source, tag, status]) │ Nonblocking test for a message │
├─────────────────────────────────┼──────────────────────────────────┤
│Irecv(buf[, source, tag]) │ Nonblocking receive │
├─────────────────────────────────┼──────────────────────────────────┤
│Ireduce(sendbuf, recvbuf[, op, │ Nonblocking Reduce to Root │
│root]) │ │
├─────────────────────────────────┼──────────────────────────────────┤
│Ireduce_scatter(sendbuf, │ Nonblocking Reduce-Scatter │
│recvbuf[, ...]) │ (vector version) │
├─────────────────────────────────┼──────────────────────────────────┤
│Ireduce_scatter_block(sendbuf, │ Nonblocking Reduce-Scatter Block │
│recvbuf[, op]) │ (regular, non-vector version) │
├─────────────────────────────────┼──────────────────────────────────┤
│Irsend(buf, dest[, tag]) │ Nonblocking send in ready mode │
├─────────────────────────────────┼──────────────────────────────────┤
│Is_inter() │ Test to see if a comm is an │
│ │ intercommunicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Is_intra() │ Test to see if a comm is an │
│ │ intracommunicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Iscatter(sendbuf, recvbuf[, │ Nonblocking Scatter │
│root]) │ │
├─────────────────────────────────┼──────────────────────────────────┤
│Iscatterv(sendbuf, recvbuf[, │ Nonblocking Scatter Vector │
│root]) │ │
├─────────────────────────────────┼──────────────────────────────────┤
│Isend(buf, dest[, tag]) │ Nonblocking send │
├─────────────────────────────────┼──────────────────────────────────┤
│Issend(buf, dest[, tag]) │ Nonblocking send in synchronous │
│ │ mode │
├─────────────────────────────────┼──────────────────────────────────┤
│Join(fd) │ Create a intercommunicator by │
│ │ joining two processes connected │
│ │ by a socket │
├─────────────────────────────────┼──────────────────────────────────┤
│Mprobe([source, tag, status]) │ Blocking test for a matched │
│ │ message │
├─────────────────────────────────┼──────────────────────────────────┤
│Probe([source, tag, status]) │ Blocking test for a message │
├─────────────────────────────────┼──────────────────────────────────┤
│Recv(buf[, source, tag, status]) │ Blocking receive │
├─────────────────────────────────┼──────────────────────────────────┤
│Recv_init(buf[, source, tag]) │ Create a persistent request for │
│ │ a receive │
├─────────────────────────────────┼──────────────────────────────────┤
│Reduce(sendbuf, recvbuf[, op, │ Reduce to Root │
│root]) │ │
├─────────────────────────────────┼──────────────────────────────────┤
│Reduce_scatter(sendbuf, │ Reduce-Scatter (vector version) │
│recvbuf[, ...]) │ │
├─────────────────────────────────┼──────────────────────────────────┤
│Reduce_scatter_block(sendbuf, │ Reduce-Scatter Block (regular, │
│recvbuf[, op]) │ non-vector version) │
├─────────────────────────────────┼──────────────────────────────────┤
│Rsend(buf, dest[, tag]) │ Blocking send in ready mode │
├─────────────────────────────────┼──────────────────────────────────┤
│Rsend_init(buf, dest[, tag]) │ Persistent request for a send in │
│ │ ready mode │
├─────────────────────────────────┼──────────────────────────────────┤
│Scatter(sendbuf, recvbuf[, │ Scatter data from one process to │
│root]) │ all other processes in a group │
├─────────────────────────────────┼──────────────────────────────────┤
│Scatterv(sendbuf, recvbuf[, │ Scatter Vector, scatter data │
│root]) │ from one process to all other │
│ │ processes in a group providing │
│ │ different amount of data and │
│ │ displacements at the sending │
│ │ side │
├─────────────────────────────────┼──────────────────────────────────┤
│Send(buf, dest[, tag]) │ Blocking send │
├─────────────────────────────────┼──────────────────────────────────┤
│Send_init(buf, dest[, tag]) │ Create a persistent request for │
│ │ a standard send │
├─────────────────────────────────┼──────────────────────────────────┤
│Sendrecv(sendbuf, dest[, │ Send and receive a message │
│sendtag, recvbuf, ...]) │ │
├─────────────────────────────────┼──────────────────────────────────┤
│Sendrecv_replace(buf, dest[, │ Send and receive a message │
│sendtag, ...]) │ │
├─────────────────────────────────┼──────────────────────────────────┤
│Set_attr(keyval, attrval) │ Store attribute value associated │
│ │ with a key │
├─────────────────────────────────┼──────────────────────────────────┤
│Set_errhandler(errhandler) │ Set the error handler for a │
│ │ communicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Set_info(info) │ Set new values for the hints │
│ │ associated with a communicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Set_name(name) │ Set the print name for this │
│ │ communicator │
├─────────────────────────────────┼──────────────────────────────────┤
│Split([color, key]) │ Split communicator by color and │
│ │ key │
├─────────────────────────────────┼──────────────────────────────────┤
│Split_type(split_type[, key, │ Split communicator by split type │
│info]) │ │
├─────────────────────────────────┼──────────────────────────────────┤
│Ssend(buf, dest[, tag]) │ Blocking send in synchronous │
│ │ mode │
├─────────────────────────────────┼──────────────────────────────────┤
│Ssend_init(buf, dest[, tag]) │ Persistent request for a send in │
│ │ synchronous mode │
├─────────────────────────────────┼──────────────────────────────────┤
│allgather(sendobj) │ Gather to All │
├─────────────────────────────────┼──────────────────────────────────┤
│allreduce(sendobj[, op]) │ Reduce to All │
├─────────────────────────────────┼──────────────────────────────────┤
│alltoall(sendobj) │ All to All Scatter/Gather │
├─────────────────────────────────┼──────────────────────────────────┤
│barrier() │ Barrier │
├─────────────────────────────────┼──────────────────────────────────┤
│bcast(obj[, root]) │ Broadcast │
├─────────────────────────────────┼──────────────────────────────────┤
│bsend(obj, dest[, tag]) │ Send in buffered mode │
├─────────────────────────────────┼──────────────────────────────────┤
│f2py(arg) │ │
├─────────────────────────────────┼──────────────────────────────────┤
│gather(sendobj[, root]) │ Gather │
├─────────────────────────────────┼──────────────────────────────────┤
│ibsend(obj, dest[, tag]) │ Nonblocking send in buffered │
│ │ mode │
├─────────────────────────────────┼──────────────────────────────────┤
│improbe([source, tag, status]) │ Nonblocking test for a matched │
│ │ message │
├─────────────────────────────────┼──────────────────────────────────┤
│iprobe([source, tag, status]) │ Nonblocking test for a message │
├─────────────────────────────────┼──────────────────────────────────┤
│irecv([buf, source, tag]) │ Nonblocking receive │
├─────────────────────────────────┼──────────────────────────────────┤
│isend(obj, dest[, tag]) │ Nonblocking send │
├─────────────────────────────────┼──────────────────────────────────┤
│issend(obj, dest[, tag]) │ Nonblocking send in synchronous │
│ │ mode │
├─────────────────────────────────┼──────────────────────────────────┤
│mprobe([source, tag, status]) │ Blocking test for a matched │
│ │ message │
├─────────────────────────────────┼──────────────────────────────────┤
│probe([source, tag, status]) │ Blocking test for a message │
├─────────────────────────────────┼──────────────────────────────────┤
│py2f() │ │
├─────────────────────────────────┼──────────────────────────────────┤
│recv([buf, source, tag, status]) │ Receive │
├─────────────────────────────────┼──────────────────────────────────┤
│reduce(sendobj[, op, root]) │ Reduce to Root │
├─────────────────────────────────┼──────────────────────────────────┤
│scatter(sendobj[, root]) │ Scatter │
├─────────────────────────────────┼──────────────────────────────────┤
│send(obj, dest[, tag]) │ Send │
├─────────────────────────────────┼──────────────────────────────────┤
│sendrecv(sendobj, dest[, │ Send and Receive │
│sendtag, recvbuf, ...]) │ │
├─────────────────────────────────┼──────────────────────────────────┤
│ssend(obj, dest[, tag]) │ Send in synchronous mode │
└─────────────────────────────────┴──────────────────────────────────┘
Attributes Summary
┌─────────┬──────────────────────────────────┐
│group │ communicator group │
├─────────┼──────────────────────────────────┤
│info │ communicator info │
├─────────┼──────────────────────────────────┤
│is_inter │ is intercommunicator │
├─────────┼──────────────────────────────────┤
│is_intra │ is intracommunicator │
├─────────┼──────────────────────────────────┤
│is_topo │ is a topology communicator │
├─────────┼──────────────────────────────────┤
│name │ communicator name │
├─────────┼──────────────────────────────────┤
│rank │ rank of this process in │
│ │ communicator │
├─────────┼──────────────────────────────────┤
│size │ number of processes in │
│ │ communicator │
├─────────┼──────────────────────────────────┤
│topology │ communicator topology type │
└─────────┴──────────────────────────────────┘
Methods Documentation
Abort(errorcode=0)
Terminate MPI execution environment
WARNING:
This is a direct call, use it with care!!!.
Parameters
errorcode (int)
Return type
NoReturn
Allgather(sendbuf, recvbuf)
Gather to All, gather data from all processes and distribute it to all other
processes in a group
Parameters
• sendbuf (Union[BufSpec, InPlace])
• recvbuf (BufSpecB)
Return type
None
Allgatherv(sendbuf, recvbuf)
Gather to All Vector, gather data from all processes and distribute it to
all other processes in a group providing different amount of data and
displacements
Parameters
• sendbuf (Union[BufSpec, InPlace])
• recvbuf (BufSpecV)
Return type
None
Allreduce(sendbuf, recvbuf, op=SUM)
Reduce to All
Parameters
• sendbuf (Union[BufSpec, InPlace])
• recvbuf (BufSpec)
• op (Op)
Return type
None
Alltoall(sendbuf, recvbuf)
All to All Scatter/Gather, send data from all to all processes in a group
Parameters
• sendbuf (Union[BufSpecB, InPlace])
• recvbuf (BufSpecB)
Return type
None
Alltoallv(sendbuf, recvbuf)
All to All Scatter/Gather Vector, send data from all to all processes in a
group providing different amount of data and displacements
Parameters
• sendbuf (Union[BufSpecV, InPlace])
• recvbuf (BufSpecV)
Return type
None
Alltoallw(sendbuf, recvbuf)
Generalized All-to-All communication allowing different counts,
displacements and datatypes for each partner
Parameters
• sendbuf (Union[BufSpecW, InPlace])
• recvbuf (BufSpecW)
Return type
None
Barrier()
Barrier synchronization
Return type
None
Bcast(buf, root=0)
Broadcast a message from one process to all other processes in a group
Parameters
• buf (BufSpec)
• root (int)
Return type
None
Bsend(buf, dest, tag=0)
Blocking send in buffered mode
Parameters
• buf (BufSpec)
• dest (int)
• tag (int)
Return type
None
Bsend_init(buf, dest, tag=0)
Persistent request for a send in buffered mode
Parameters
• buf (BufSpec)
• dest (int)
• tag (int)
Return type
Request
Call_errhandler(errorcode)
Call the error handler installed on a communicator
Parameters
errorcode (int)
Return type
None
Clone()
Clone an existing communicator
Return type
Comm
classmethod Compare(comm1, comm2)
Compare two communicators
Parameters
• comm1 (Comm)
• comm2 (Comm)
Return type
int
Create(group)
Create communicator from group
Parameters
group (Group)
Return type
Comm
Create_group(group, tag=0)
Create communicator from group
Parameters
• group (Group)
• tag (int)
Return type
Comm
classmethod Create_keyval(copy_fn=None, delete_fn=None, nopython=False)
Create a new attribute key for communicators
Parameters
• copy_fn (Optional[Callable[[Comm, int, Any], Any]])
• delete_fn (Optional[Callable[[Comm, int, Any], None]])
• nopython (bool)
Return type
int
Delete_attr(keyval)
Delete attribute value associated with a key
Parameters
keyval (int)
Return type
None
Disconnect()
Disconnect from a communicator
Return type
None
Dup(info=None)
Duplicate an existing communicator
Parameters
info (Optional[Info])
Return type
Comm
Dup_with_info(info)
Duplicate an existing communicator
Parameters
info (Info)
Return type
Comm
Free() Free a communicator
Return type
None
classmethod Free_keyval(keyval)
Free an attribute key for communicators
Parameters
keyval (int)
Return type
int
Gather(sendbuf, recvbuf, root=0)
Gather together values from a group of processes
Parameters
• sendbuf (Union[BufSpec, InPlace])
• recvbuf (Optional[BufSpecB])
• root (int)
Return type
None
Gatherv(sendbuf, recvbuf, root=0)
Gather Vector, gather data to one process from all other processes in a
group providing different amount of data and displacements at the receiving
sides
Parameters
• sendbuf (Union[BufSpec, InPlace])
• recvbuf (Optional[BufSpecV])
• root (int)
Return type
None
Get_attr(keyval)
Retrieve attribute value by key
Parameters
keyval (int)
Return type
Optional[Union[int, Any]]
Get_errhandler()
Get the error handler for a communicator
Return type
Errhandler
Get_group()
Access the group associated with a communicator
Return type
Group
Get_info()
Return the hints for a communicator that are currently in use
Return type
Info
Get_name()
Get the print name for this communicator
Return type
str
classmethod Get_parent()
Return the parent intercommunicator for this process
Return type
Intercomm
Get_rank()
Return the rank of this process in a communicator
Return type
int
Get_size()
Return the number of processes in a communicator
Return type
int
Get_topology()
Determine the type of topology (if any) associated with a communicator
Return type
int
Iallgather(sendbuf, recvbuf)
Nonblocking Gather to All
Parameters
• sendbuf (Union[BufSpec, InPlace])
• recvbuf (BufSpecB)
Return type
Request
Iallgatherv(sendbuf, recvbuf)
Nonblocking Gather to All Vector
Parameters
• sendbuf (Union[BufSpec, InPlace])
• recvbuf (BufSpecV)
Return type
Request
Iallreduce(sendbuf, recvbuf, op=SUM)
Nonblocking Reduce to All
Parameters
• sendbuf (Union[BufSpec, InPlace])
• recvbuf (BufSpec)
• op (Op)
Return type
Request
Ialltoall(sendbuf, recvbuf)
Nonblocking All to All Scatter/Gather
Parameters
• sendbuf (Union[BufSpecB, InPlace])
• recvbuf (BufSpecB)
Return type
Request
Ialltoallv(sendbuf, recvbuf)
Nonblocking All to All Scatter/Gather Vector
Parameters
• sendbuf (Union[BufSpecV, InPlace])
• recvbuf (BufSpecV)
Return type
Request
Ialltoallw(sendbuf, recvbuf)
Nonblocking Generalized All-to-All
Parameters
• sendbuf (Union[BufSpecW, InPlace])
• recvbuf (BufSpecW)
Return type
Request
Ibarrier()
Nonblocking Barrier
Return type
Request
Ibcast(buf, root=0)
Nonblocking Broadcast
Parameters
• buf (BufSpec)
• root (int)
Return type
Request
Ibsend(buf, dest, tag=0)
Nonblocking send in buffered mode
Parameters
• buf (BufSpec)
• dest (int)
• tag (int)
Return type
Request
Idup() Nonblocking duplicate an existing communicator
Return type
Tuple[Comm, Request]
Igather(sendbuf, recvbuf, root=0)
Nonblocking Gather
Parameters
• sendbuf (Union[BufSpec, InPlace])
• recvbuf (Optional[BufSpecB])
• root (int)
Return type
Request
Igatherv(sendbuf, recvbuf, root=0)
Nonblocking Gather Vector
Parameters
• sendbuf (Union[BufSpec, InPlace])
• recvbuf (Optional[BufSpecV])
• root (int)
Return type
Request
Improbe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
Nonblocking test for a matched message
Parameters
• source (int)
• tag (int)
• status (Optional[Status])
Return type
Optional[Message]
Iprobe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
Nonblocking test for a message
Parameters
• source (int)
• tag (int)
• status (Optional[Status])
Return type
bool
Irecv(buf, source=ANY_SOURCE, tag=ANY_TAG)
Nonblocking receive
Parameters
• buf (BufSpec)
• source (int)
• tag (int)
Return type
Request
Ireduce(sendbuf, recvbuf, op=SUM, root=0)
Nonblocking Reduce to Root
Parameters
• sendbuf (Union[BufSpec, InPlace])
• recvbuf (Optional[BufSpec])
• op (Op)
• root (int)
Return type
Request
Ireduce_scatter(sendbuf, recvbuf, recvcounts=None, op=SUM)
Nonblocking Reduce-Scatter (vector version)
Parameters
• sendbuf (Union[BufSpec, InPlace])
• recvbuf (BufSpec)
• recvcounts (Optional[Sequence[int]])
• op (Op)
Return type
Request
Ireduce_scatter_block(sendbuf, recvbuf, op=SUM)
Nonblocking Reduce-Scatter Block (regular, non-vector version)
Parameters
• sendbuf (Union[BufSpecB, InPlace])
• recvbuf (Union[BufSpec, BufSpecB])
• op (Op)
Return type
Request
Irsend(buf, dest, tag=0)
Nonblocking send in ready mode
Parameters
• buf (BufSpec)
• dest (int)
• tag (int)
Return type
Request
Is_inter()
Test to see if a comm is an intercommunicator
Return type
bool
Is_intra()
Test to see if a comm is an intracommunicator
Return type
bool
Iscatter(sendbuf, recvbuf, root=0)
Nonblocking Scatter
Parameters
• sendbuf (Optional[BufSpecB])
• recvbuf (Union[BufSpec, InPlace])
• root (int)
Return type
Request
Iscatterv(sendbuf, recvbuf, root=0)
Nonblocking Scatter Vector
Parameters
• sendbuf (Optional[BufSpecV])
• recvbuf (Union[BufSpec, InPlace])
• root (int)
Return type
Request
Isend(buf, dest, tag=0)
Nonblocking send
Parameters
• buf (BufSpec)
• dest (int)
• tag (int)
Return type
Request
Issend(buf, dest, tag=0)
Nonblocking send in synchronous mode
Parameters
• buf (BufSpec)
• dest (int)
• tag (int)
Return type
Request
classmethod Join(fd)
Create a intercommunicator by joining two processes connected by a socket
Parameters
fd (int)
Return type
Intercomm
Mprobe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
Blocking test for a matched message
Parameters
• source (int)
• tag (int)
• status (Optional[Status])
Return type
Message
Probe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
Blocking test for a message
NOTE:
This function blocks until the message arrives.
Parameters
• source (int)
• tag (int)
• status (Optional[Status])
Return type
Literal[True]
Recv(buf, source=ANY_SOURCE, tag=ANY_TAG, status=None)
Blocking receive
NOTE:
This function blocks until the message is received
Parameters
• buf (BufSpec)
• source (int)
• tag (int)
• status (Optional[Status])
Return type
None
Recv_init(buf, source=ANY_SOURCE, tag=ANY_TAG)
Create a persistent request for a receive
Parameters
• buf (BufSpec)
• source (int)
• tag (int)
Return type
Prequest
Reduce(sendbuf, recvbuf, op=SUM, root=0)
Reduce to Root
Parameters
• sendbuf (Union[BufSpec, InPlace])
• recvbuf (Optional[BufSpec])
• op (Op)
• root (int)
Return type
None
Reduce_scatter(sendbuf, recvbuf, recvcounts=None, op=SUM)
Reduce-Scatter (vector version)
Parameters
• sendbuf (Union[BufSpec, InPlace])
• recvbuf (BufSpec)
• recvcounts (Optional[Sequence[int]])
• op (Op)
Return type
None
Reduce_scatter_block(sendbuf, recvbuf, op=SUM)
Reduce-Scatter Block (regular, non-vector version)
Parameters
• sendbuf (Union[BufSpecB, InPlace])
• recvbuf (Union[BufSpec, BufSpecB])
• op (Op)
Return type
None
Rsend(buf, dest, tag=0)
Blocking send in ready mode
Parameters
• buf (BufSpec)
• dest (int)
• tag (int)
Return type
None
Rsend_init(buf, dest, tag=0)
Persistent request for a send in ready mode
Parameters
• buf (BufSpec)
• dest (int)
• tag (int)
Return type
Request
Scatter(sendbuf, recvbuf, root=0)
Scatter data from one process to all other processes in a group
Parameters
• sendbuf (Optional[BufSpecB])
• recvbuf (Union[BufSpec, InPlace])
• root (int)
Return type
None
Scatterv(sendbuf, recvbuf, root=0)
Scatter Vector, scatter data from one process to all other processes in a
group providing different amount of data and displacements at the sending
side
Parameters
• sendbuf (Optional[BufSpecV])
• recvbuf (Union[BufSpec, InPlace])
• root (int)
Return type
None
Send(buf, dest, tag=0)
Blocking send
NOTE:
This function may block until the message is received. Whether or not
Send blocks depends on several factors and is implementation dependent
Parameters
• buf (BufSpec)
• dest (int)
• tag (int)
Return type
None
Send_init(buf, dest, tag=0)
Create a persistent request for a standard send
Parameters
• buf (BufSpec)
• dest (int)
• tag (int)
Return type
Prequest
Sendrecv(sendbuf, dest, sendtag=0, recvbuf=None, source=ANY_SOURCE,
recvtag=ANY_TAG, status=None)
Send and receive a message
NOTE:
This function is guaranteed not to deadlock in situations where pairs of
blocking sends and receives may deadlock.
CAUTION:
A common mistake when using this function is to mismatch the tags with
the source and destination ranks, which can result in deadlock.
Parameters
• sendbuf (BufSpec)
• dest (int)
• sendtag (int)
• recvbuf (BufSpec)
• source (int)
• recvtag (int)
• status (Optional[Status])
Return type
None
Sendrecv_replace(buf, dest, sendtag=0, source=ANY_SOURCE, recvtag=ANY_TAG,
status=None)
Send and receive a message
NOTE:
This function is guaranteed not to deadlock in situations where pairs of
blocking sends and receives may deadlock.
CAUTION:
A common mistake when using this function is to mismatch the tags with
the source and destination ranks, which can result in deadlock.
Parameters
• buf (BufSpec)
• dest (int)
• sendtag (int)
• source (int)
• recvtag (int)
• status (Optional[Status])
Return type
None
Set_attr(keyval, attrval)
Store attribute value associated with a key
Parameters
• keyval (int)
• attrval (Any)
Return type
None
Set_errhandler(errhandler)
Set the error handler for a communicator
Parameters
errhandler (Errhandler)
Return type
None
Set_info(info)
Set new values for the hints associated with a communicator
Parameters
info (Info)
Return type
None
Set_name(name)
Set the print name for this communicator
Parameters
name (str)
Return type
None
Split(color=0, key=0)
Split communicator by color and key
Parameters
• color (int)
• key (int)
Return type
Comm
Split_type(split_type, key=0, info=INFO_NULL)
Split communicator by split type
Parameters
• split_type (int)
• key (int)
• info (Info)
Return type
Comm
Ssend(buf, dest, tag=0)
Blocking send in synchronous mode
Parameters
• buf (BufSpec)
• dest (int)
• tag (int)
Return type
None
Ssend_init(buf, dest, tag=0)
Persistent request for a send in synchronous mode
Parameters
• buf (BufSpec)
• dest (int)
• tag (int)
Return type
Request
allgather(sendobj)
Gather to All
Parameters
sendobj (Any)
Return type
List[Any]
allreduce(sendobj, op=SUM)
Reduce to All
Parameters
• sendobj (Any)
• op (Union[Op, Callable[[Any, Any], Any]])
Return type
Any
alltoall(sendobj)
All to All Scatter/Gather
Parameters
sendobj (Sequence[Any])
Return type
List[Any]
barrier()
Barrier
Return type
None
bcast(obj, root=0)
Broadcast
Parameters
• obj (Any)
• root (int)
Return type
Any
bsend(obj, dest, tag=0)
Send in buffered mode
Parameters
• obj (Any)
• dest (int)
• tag (int)
Return type
None
classmethod f2py(arg)
Parameters
arg (int)
Return type
Comm
gather(sendobj, root=0)
Gather
Parameters
• sendobj (Any)
• root (int)
Return type
Optional[List[Any]]
ibsend(obj, dest, tag=0)
Nonblocking send in buffered mode
Parameters
• obj (Any)
• dest (int)
• tag (int)
Return type
Request
improbe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
Nonblocking test for a matched message
Parameters
• source (int)
• tag (int)
• status (Optional[Status])
Return type
Optional[Message]
iprobe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
Nonblocking test for a message
Parameters
• source (int)
• tag (int)
• status (Optional[Status])
Return type
bool
irecv(buf=None, source=ANY_SOURCE, tag=ANY_TAG)
Nonblocking receive
Parameters
• buf (Optional[Buffer])
• source (int)
• tag (int)
Return type
Request
isend(obj, dest, tag=0)
Nonblocking send
Parameters
• obj (Any)
• dest (int)
• tag (int)
Return type
Request
issend(obj, dest, tag=0)
Nonblocking send in synchronous mode
Parameters
• obj (Any)
• dest (int)
• tag (int)
Return type
Request
mprobe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
Blocking test for a matched message
Parameters
• source (int)
• tag (int)
• status (Optional[Status])
Return type
Message
probe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
Blocking test for a message
Parameters
• source (int)
• tag (int)
• status (Optional[Status])
Return type
Literal[True]
py2f()
Return type
int
recv(buf=None, source=ANY_SOURCE, tag=ANY_TAG, status=None)
Receive
Parameters
• buf (Optional[Buffer])
• source (int)
• tag (int)
• status (Optional[Status])
Return type
Any
reduce(sendobj, op=SUM, root=0)
Reduce to Root
Parameters
• sendobj (Any)
• op (Union[Op, Callable[[Any, Any], Any]])
• root (int)
Return type
Optional[Any]
scatter(sendobj, root=0)
Scatter
Parameters
• sendobj (Sequence[Any])
• root (int)
Return type
Any
send(obj, dest, tag=0)
Send
Parameters
• obj (Any)
• dest (int)
• tag (int)
Return type
None
sendrecv(sendobj, dest, sendtag=0, recvbuf=None, source=ANY_SOURCE,
recvtag=ANY_TAG, status=None)
Send and Receive
Parameters
• sendobj (Any)
• dest (int)
• sendtag (int)
• recvbuf (Optional[Buffer])
• source (int)
• recvtag (int)
• status (Optional[Status])
Return type
Any
ssend(obj, dest, tag=0)
Send in synchronous mode
Parameters
• obj (Any)
• dest (int)
• tag (int)
Return type
None
Attributes Documentation
group communicator group
info communicator info
is_inter
is intercommunicator
is_intra
is intracommunicator
is_topo
is a topology communicator
name communicator name
rank rank of this process in communicator
size number of processes in communicator
topology
communicator topology type
mpi4py.MPI.Datatype
class mpi4py.MPI.Datatype(datatype=None)
Bases: object
Datatype object
Parameters
datatype (Optional[Datatype])
Return type
Datatype
static __new__(cls, datatype=None)
Parameters
datatype (Optional[Datatype])
Return type
Datatype
Methods Summary
┌───────────────────────────────────┬──────────────────────────────────┐
│Commit() │ Commit the datatype │
├───────────────────────────────────┼──────────────────────────────────┤
│Create_contiguous(count) │ Create a contiguous datatype │
├───────────────────────────────────┼──────────────────────────────────┤
│Create_darray(size, rank, │ Create a datatype representing │
│gsizes, distribs, ...) │ an HPF-like distributed array on │
│ │ Cartesian process grids │
├───────────────────────────────────┼──────────────────────────────────┤
│Create_f90_complex(p, r) │ Return a bounded complex │
│ │ datatype │
├───────────────────────────────────┼──────────────────────────────────┤
│Create_f90_integer(r) │ Return a bounded integer │
│ │ datatype │
├───────────────────────────────────┼──────────────────────────────────┤
│Create_f90_real(p, r) │ Return a bounded real datatype │
├───────────────────────────────────┼──────────────────────────────────┤
│Create_hindexed(blocklengths, │ Create an indexed datatype with │
│displacements) │ displacements in bytes │
├───────────────────────────────────┼──────────────────────────────────┤
│Create_hindexed_block(blocklength, │ Create an indexed datatype with │
│displacements) │ constant-sized blocks and │
│ │ displacements in bytes │
├───────────────────────────────────┼──────────────────────────────────┤
│Create_hvector(count, blocklength, │ Create a vector (strided) │
│stride) │ datatype │
├───────────────────────────────────┼──────────────────────────────────┤
│Create_indexed(blocklengths, │ Create an indexed datatype │
│displacements) │ │
├───────────────────────────────────┼──────────────────────────────────┤
│Create_indexed_block(blocklength, │ Create an indexed datatype with │
│displacements) │ constant-sized blocks │
├───────────────────────────────────┼──────────────────────────────────┤
│Create_keyval([copy_fn, delete_fn, │ Create a new attribute key for │
│nopython]) │ datatypes │
├───────────────────────────────────┼──────────────────────────────────┤
│Create_resized(lb, extent) │ Create a datatype with a new │
│ │ lower bound and extent │
├───────────────────────────────────┼──────────────────────────────────┤
│Create_struct(blocklengths, │ Create an datatype from a │
│displacements, ...) │ general set of block sizes, │
│ │ displacements and datatypes │
├───────────────────────────────────┼──────────────────────────────────┤
│Create_subarray(sizes, subsizes, │ Create a datatype for a subarray │
│starts[, order]) │ of a regular, multidimensional │
│ │ array │
├───────────────────────────────────┼──────────────────────────────────┤
│Create_vector(count, blocklength, │ Create a vector (strided) │
│stride) │ datatype │
├───────────────────────────────────┼──────────────────────────────────┤
│Delete_attr(keyval) │ Delete attribute value │
│ │ associated with a key │
├───────────────────────────────────┼──────────────────────────────────┤
│Dup() │ Duplicate a datatype │
├───────────────────────────────────┼──────────────────────────────────┤
│Free() │ Free the datatype │
├───────────────────────────────────┼──────────────────────────────────┤
│Free_keyval(keyval) │ Free an attribute key for │
│ │ datatypes │
├───────────────────────────────────┼──────────────────────────────────┤
│Get_attr(keyval) │ Retrieve attribute value by key │
├───────────────────────────────────┼──────────────────────────────────┤
│Get_contents() │ Retrieve the actual arguments │
│ │ used in the call that created a │
│ │ datatype │
├───────────────────────────────────┼──────────────────────────────────┤
│Get_envelope() │ Return information on the number │
│ │ and type of input arguments used │
│ │ in the call that created a │
│ │ datatype │
├───────────────────────────────────┼──────────────────────────────────┤
│Get_extent() │ Return lower bound and extent of │
│ │ datatype │
├───────────────────────────────────┼──────────────────────────────────┤
│Get_name() │ Get the print name for this │
│ │ datatype │
├───────────────────────────────────┼──────────────────────────────────┤
│Get_size() │ Return the number of bytes │
│ │ occupied by entries in the │
│ │ datatype │
├───────────────────────────────────┼──────────────────────────────────┤
│Get_true_extent() │ Return the true lower bound and │
│ │ extent of a datatype │
├───────────────────────────────────┼──────────────────────────────────┤
│Match_size(typeclass, size) │ Find a datatype matching a │
│ │ specified size in bytes │
├───────────────────────────────────┼──────────────────────────────────┤
│Pack(inbuf, outbuf, position, │ Pack into contiguous memory │
│comm) │ according to datatype. │
├───────────────────────────────────┼──────────────────────────────────┤
│Pack_external(datarep, inbuf, │ Pack into contiguous memory │
│outbuf, position) │ according to datatype, using a │
│ │ portable data representation │
│ │ (external32). │
├───────────────────────────────────┼──────────────────────────────────┤
│Pack_external_size(datarep, count) │ Return the upper bound on the │
│ │ amount of space (in bytes) │
│ │ needed to pack a message │
│ │ according to datatype, using a │
│ │ portable data representation │
│ │ (external32). │
├───────────────────────────────────┼──────────────────────────────────┤
│Pack_size(count, comm) │ Return the upper bound on the │
│ │ amount of space (in bytes) │
│ │ needed to pack a message │
│ │ according to datatype. │
├───────────────────────────────────┼──────────────────────────────────┤
│Set_attr(keyval, attrval) │ Store attribute value associated │
│ │ with a key │
├───────────────────────────────────┼──────────────────────────────────┤
│Set_name(name) │ Set the print name for this │
│ │ datatype │
├───────────────────────────────────┼──────────────────────────────────┤
│Unpack(inbuf, position, outbuf, │ Unpack from contiguous memory │
│comm) │ according to datatype. │
├───────────────────────────────────┼──────────────────────────────────┤
│Unpack_external(datarep, inbuf, │ Unpack from contiguous memory │
│position, outbuf) │ according to datatype, using a │
│ │ portable data representation │
│ │ (external32). │
├───────────────────────────────────┼──────────────────────────────────┤
│decode() │ Convenience method for decoding │
│ │ a datatype │
├───────────────────────────────────┼──────────────────────────────────┤
│f2py(arg) │ │
├───────────────────────────────────┼──────────────────────────────────┤
│py2f() │ │
└───────────────────────────────────┴──────────────────────────────────┘
Attributes Summary
┌──────────────┬──────────────────────────┐
│combiner │ datatype combiner │
├──────────────┼──────────────────────────┤
│contents │ datatype contents │
├──────────────┼──────────────────────────┤
│envelope │ datatype envelope │
├──────────────┼──────────────────────────┤
│extent │ │
├──────────────┼──────────────────────────┤
│is_named │ is a named datatype │
├──────────────┼──────────────────────────┤
│is_predefined │ is a predefined datatype │
├──────────────┼──────────────────────────┤
│lb │ lower bound │
├──────────────┼──────────────────────────┤
│name │ datatype name │
├──────────────┼──────────────────────────┤
│size │ │
├──────────────┼──────────────────────────┤
│true_extent │ true extent │
├──────────────┼──────────────────────────┤
│true_lb │ true lower bound │
├──────────────┼──────────────────────────┤
│true_ub │ true upper bound │
├──────────────┼──────────────────────────┤
│ub │ upper bound │
└──────────────┴──────────────────────────┘
Methods Documentation
Commit()
Commit the datatype
Return type
Datatype
Create_contiguous(count)
Create a contiguous datatype
Parameters
count (int)
Return type
Datatype
Create_darray(size, rank, gsizes, distribs, dargs, psizes, order=ORDER_C)
Create a datatype representing an HPF-like distributed array on Cartesian
process grids
Parameters
• size (int)
• rank (int)
• gsizes (Sequence[int])
• distribs (Sequence[int])
• dargs (Sequence[int])
• psizes (Sequence[int])
• order (int)
Return type
Datatype
classmethod Create_f90_complex(p, r)
Return a bounded complex datatype
Parameters
• p (int)
• r (int)
Return type
Datatype
classmethod Create_f90_integer(r)
Return a bounded integer datatype
Parameters
r (int)
Return type
Datatype
classmethod Create_f90_real(p, r)
Return a bounded real datatype
Parameters
• p (int)
• r (int)
Return type
Datatype
Create_hindexed(blocklengths, displacements)
Create an indexed datatype with displacements in bytes
Parameters
• blocklengths (Sequence[int])
• displacements (Sequence[int])
Return type
Datatype
Create_hindexed_block(blocklength, displacements)
Create an indexed datatype with constant-sized blocks and displacements in
bytes
Parameters
• blocklength (int)
• displacements (Sequence[int])
Return type
Datatype
Create_hvector(count, blocklength, stride)
Create a vector (strided) datatype
Parameters
• count (int)
• blocklength (int)
• stride (int)
Return type
Datatype
Create_indexed(blocklengths, displacements)
Create an indexed datatype
Parameters
• blocklengths (Sequence[int])
• displacements (Sequence[int])
Return type
Datatype
Create_indexed_block(blocklength, displacements)
Create an indexed datatype with constant-sized blocks
Parameters
• blocklength (int)
• displacements (Sequence[int])
Return type
Datatype
classmethod Create_keyval(copy_fn=None, delete_fn=None, nopython=False)
Create a new attribute key for datatypes
Parameters
• copy_fn (Optional[Callable[[Datatype, int, Any], Any]])
• delete_fn (Optional[Callable[[Datatype, int, Any], None]])
• nopython (bool)
Return type
int
Create_resized(lb, extent)
Create a datatype with a new lower bound and extent
Parameters
• lb (int)
• extent (int)
Return type
Datatype
classmethod Create_struct(blocklengths, displacements, datatypes)
Create an datatype from a general set of block sizes, displacements and
datatypes
Parameters
• blocklengths (Sequence[int])
• displacements (Sequence[int])
• datatypes (Sequence[Datatype])
Return type
Datatype
Create_subarray(sizes, subsizes, starts, order=ORDER_C)
Create a datatype for a subarray of a regular, multidimensional array
Parameters
• sizes (Sequence[int])
• subsizes (Sequence[int])
• starts (Sequence[int])
• order (int)
Return type
Datatype
Create_vector(count, blocklength, stride)
Create a vector (strided) datatype
Parameters
• count (int)
• blocklength (int)
• stride (int)
Return type
Datatype
Delete_attr(keyval)
Delete attribute value associated with a key
Parameters
keyval (int)
Return type
None
Dup() Duplicate a datatype
Return type
Datatype
Free() Free the datatype
Return type
None
classmethod Free_keyval(keyval)
Free an attribute key for datatypes
Parameters
keyval (int)
Return type
int
Get_attr(keyval)
Retrieve attribute value by key
Parameters
keyval (int)
Return type
Optional[Union[int, Any]]
Get_contents()
Retrieve the actual arguments used in the call that created a datatype
Return type
Tuple[List[int], List[int], List[Datatype]]
Get_envelope()
Return information on the number and type of input arguments used in the
call that created a datatype
Return type
Tuple[int, int, int, int]
Get_extent()
Return lower bound and extent of datatype
Return type
Tuple[int, int]
Get_name()
Get the print name for this datatype
Return type
str
Get_size()
Return the number of bytes occupied by entries in the datatype
Return type
int
Get_true_extent()
Return the true lower bound and extent of a datatype
Return type
Tuple[int, int]
classmethod Match_size(typeclass, size)
Find a datatype matching a specified size in bytes
Parameters
• typeclass (int)
• size (int)
Return type
Datatype
Pack(inbuf, outbuf, position, comm)
Pack into contiguous memory according to datatype.
Parameters
• inbuf (BufSpec)
• outbuf (BufSpec)
• position (int)
• comm (Comm)
Return type
int
Pack_external(datarep, inbuf, outbuf, position)
Pack into contiguous memory according to datatype, using a portable data
representation (external32).
Parameters
• datarep (str)
• inbuf (BufSpec)
• outbuf (BufSpec)
• position (int)
Return type
int
Pack_external_size(datarep, count)
Return the upper bound on the amount of space (in bytes) needed to pack a
message according to datatype, using a portable data representation
(external32).
Parameters
• datarep (str)
• count (int)
Return type
int
Pack_size(count, comm)
Return the upper bound on the amount of space (in bytes) needed to pack a
message according to datatype.
Parameters
• count (int)
• comm (Comm)
Return type
int
Set_attr(keyval, attrval)
Store attribute value associated with a key
Parameters
• keyval (int)
• attrval (Any)
Return type
None
Set_name(name)
Set the print name for this datatype
Parameters
name (str)
Return type
None
Unpack(inbuf, position, outbuf, comm)
Unpack from contiguous memory according to datatype.
Parameters
• inbuf (BufSpec)
• position (int)
• outbuf (BufSpec)
• comm (Comm)
Return type
int
Unpack_external(datarep, inbuf, position, outbuf)
Unpack from contiguous memory according to datatype, using a portable data
representation (external32).
Parameters
• datarep (str)
• inbuf (BufSpec)
• position (int)
• outbuf (BufSpec)
Return type
int
decode()
Convenience method for decoding a datatype
Return type
Tuple[Datatype, str, Dict[str, Any]]
classmethod f2py(arg)
Parameters
arg (int)
Return type
Datatype
py2f()
Return type
int
Attributes Documentation
combiner
datatype combiner
contents
datatype contents
envelope
datatype envelope
extent
is_named
is a named datatype
is_predefined
is a predefined datatype
lb lower bound
name datatype name
size
true_extent
true extent
true_lb
true lower bound
true_ub
true upper bound
ub upper bound
mpi4py.MPI.Distgraphcomm
class mpi4py.MPI.Distgraphcomm(comm=None)
Bases: Topocomm
Distributed graph topology intracommunicator
Parameters
comm (Optional[Distgraphcomm])
Return type
Distgraphcomm
static __new__(cls, comm=None)
Parameters
comm (Optional[Distgraphcomm])
Return type
Distgraphcomm
Methods Summary
┌───────────────────────────┬──────────────────────────────────┐
│Get_dist_neighbors() │ Return adjacency information for │
│ │ a distributed graph topology │
├───────────────────────────┼──────────────────────────────────┤
│Get_dist_neighbors_count() │ Return adjacency information for │
│ │ a distributed graph topology │
└───────────────────────────┴──────────────────────────────────┘
Methods Documentation
Get_dist_neighbors()
Return adjacency information for a distributed graph topology
Return type
Tuple[List[int], List[int], Optional[Tuple[List[int], List[int]]]]
Get_dist_neighbors_count()
Return adjacency information for a distributed graph topology
Return type
int
mpi4py.MPI.Errhandler
class mpi4py.MPI.Errhandler(errhandler=None)
Bases: object
Error handler
Parameters
errhandler (Optional[Errhandler])
Return type
Errhandler
static __new__(cls, errhandler=None)
Parameters
errhandler (Optional[Errhandler])
Return type
Errhandler
Methods Summary
┌──────────┬───────────────────────┐
│Free() │ Free an error handler │
├──────────┼───────────────────────┤
│f2py(arg) │ │
├──────────┼───────────────────────┤
│py2f() │ │
└──────────┴───────────────────────┘
Methods Documentation
Free() Free an error handler
Return type
None
classmethod f2py(arg)
Parameters
arg (int)
Return type
Errhandler
py2f()
Return type
int
mpi4py.MPI.File
class mpi4py.MPI.File(file=None)
Bases: object
File handle
Parameters
file (Optional[File])
Return type
File
static __new__(cls, file=None)
Parameters
file (Optional[File])
Return type
File
Methods Summary
┌─────────────────────────────────┬──────────────────────────────────┐
│Call_errhandler(errorcode) │ Call the error handler installed │
│ │ on a file │
├─────────────────────────────────┼──────────────────────────────────┤
│Close() │ Close a file │
├─────────────────────────────────┼──────────────────────────────────┤
│Delete(filename[, info]) │ Delete a file │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_amode() │ Return the file access mode │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_atomicity() │ Return the atomicity mode │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_byte_offset(offset) │ Return the absolute byte │
│ │ position in the file │
│ │ corresponding to 'offset' etypes │
│ │ relative to the current view │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_errhandler() │ Get the error handler for a file │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_group() │ Return the group of processes │
│ │ that opened the file │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_info() │ Return the hints for a file that │
│ │ that are currently in use │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_position() │ Return the current position of │
│ │ the individual file pointer in │
│ │ etype units relative to the │
│ │ current view │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_position_shared() │ Return the current position of │
│ │ the shared file pointer in etype │
│ │ units relative to the current │
│ │ view │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_size() │ Return the file size │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_type_extent(datatype) │ Return the extent of datatype in │
│ │ the file │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_view() │ Return the file view │
├─────────────────────────────────┼──────────────────────────────────┤
│Iread(buf) │ Nonblocking read using │
│ │ individual file pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Iread_all(buf) │ Nonblocking collective read │
│ │ using individual file pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Iread_at(offset, buf) │ Nonblocking read using explicit │
│ │ offset │
├─────────────────────────────────┼──────────────────────────────────┤
│Iread_at_all(offset, buf) │ Nonblocking collective read │
│ │ using explicit offset │
├─────────────────────────────────┼──────────────────────────────────┤
│Iread_shared(buf) │ Nonblocking read using shared │
│ │ file pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Iwrite(buf) │ Nonblocking write using │
│ │ individual file pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Iwrite_all(buf) │ Nonblocking collective write │
│ │ using individual file pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Iwrite_at(offset, buf) │ Nonblocking write using explicit │
│ │ offset │
├─────────────────────────────────┼──────────────────────────────────┤
│Iwrite_at_all(offset, buf) │ Nonblocking collective write │
│ │ using explicit offset │
├─────────────────────────────────┼──────────────────────────────────┤
│Iwrite_shared(buf) │ Nonblocking write using shared │
│ │ file pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Open(comm, filename[, amode, │ Open a file │
│info]) │ │
├─────────────────────────────────┼──────────────────────────────────┤
│Preallocate(size) │ Preallocate storage space for a │
│ │ file │
├─────────────────────────────────┼──────────────────────────────────┤
│Read(buf[, status]) │ Read using individual file │
│ │ pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Read_all(buf[, status]) │ Collective read using individual │
│ │ file pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Read_all_begin(buf) │ Start a split collective read │
│ │ using individual file pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Read_all_end(buf[, status]) │ Complete a split collective read │
│ │ using individual file pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Read_at(offset, buf[, status]) │ Read using explicit offset │
├─────────────────────────────────┼──────────────────────────────────┤
│Read_at_all(offset, buf[, │ Collective read using explicit │
│status]) │ offset │
├─────────────────────────────────┼──────────────────────────────────┤
│Read_at_all_begin(offset, buf) │ Start a split collective read │
│ │ using explict offset │
├─────────────────────────────────┼──────────────────────────────────┤
│Read_at_all_end(buf[, status]) │ Complete a split collective read │
│ │ using explict offset │
├─────────────────────────────────┼──────────────────────────────────┤
│Read_ordered(buf[, status]) │ Collective read using shared │
│ │ file pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Read_ordered_begin(buf) │ Start a split collective read │
│ │ using shared file pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Read_ordered_end(buf[, status]) │ Complete a split collective read │
│ │ using shared file pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Read_shared(buf[, status]) │ Read using shared file pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Seek(offset[, whence]) │ Update the individual file │
│ │ pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Seek_shared(offset[, whence]) │ Update the shared file pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Set_atomicity(flag) │ Set the atomicity mode │
├─────────────────────────────────┼──────────────────────────────────┤
│Set_errhandler(errhandler) │ Set the error handler for a file │
├─────────────────────────────────┼──────────────────────────────────┤
│Set_info(info) │ Set new values for the hints │
│ │ associated with a file │
├─────────────────────────────────┼──────────────────────────────────┤
│Set_size(size) │ Sets the file size │
├─────────────────────────────────┼──────────────────────────────────┤
│Set_view([disp, etype, filetype, │ Set the file view │
│datarep, info]) │ │
├─────────────────────────────────┼──────────────────────────────────┤
│Sync() │ Causes all previous writes to be │
│ │ transferred to the storage │
│ │ device │
├─────────────────────────────────┼──────────────────────────────────┤
│Write(buf[, status]) │ Write using individual file │
│ │ pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Write_all(buf[, status]) │ Collective write using │
│ │ individual file pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Write_all_begin(buf) │ Start a split collective write │
│ │ using individual file pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Write_all_end(buf[, status]) │ Complete a split collective │
│ │ write using individual file │
│ │ pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Write_at(offset, buf[, status]) │ Write using explicit offset │
├─────────────────────────────────┼──────────────────────────────────┤
│Write_at_all(offset, buf[, │ Collective write using explicit │
│status]) │ offset │
├─────────────────────────────────┼──────────────────────────────────┤
│Write_at_all_begin(offset, buf) │ Start a split collective write │
│ │ using explict offset │
├─────────────────────────────────┼──────────────────────────────────┤
│Write_at_all_end(buf[, status]) │ Complete a split collective │
│ │ write using explict offset │
├─────────────────────────────────┼──────────────────────────────────┤
│Write_ordered(buf[, status]) │ Collective write using shared │
│ │ file pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Write_ordered_begin(buf) │ Start a split collective write │
│ │ using shared file pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Write_ordered_end(buf[, status]) │ Complete a split collective │
│ │ write using shared file pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│Write_shared(buf[, status]) │ Write using shared file pointer │
├─────────────────────────────────┼──────────────────────────────────┤
│f2py(arg) │ │
├─────────────────────────────────┼──────────────────────────────────┤
│py2f() │ │
└─────────────────────────────────┴──────────────────────────────────┘
Attributes Summary
┌──────────┬──────────────────┐
│amode │ file access mode │
├──────────┼──────────────────┤
│atomicity │ │
├──────────┼──────────────────┤
│group │ file group │
├──────────┼──────────────────┤
│info │ file info │
├──────────┼──────────────────┤
│size │ file size │
└──────────┴──────────────────┘
Methods Documentation
Call_errhandler(errorcode)
Call the error handler installed on a file
Parameters
errorcode (int)
Return type
None
Close()
Close a file
Return type
None
classmethod Delete(filename, info=INFO_NULL)
Delete a file
Parameters
• filename (str)
• info (Info)
Return type
None
Get_amode()
Return the file access mode
Return type
int
Get_atomicity()
Return the atomicity mode
Return type
bool
Get_byte_offset(offset)
Return the absolute byte position in the file corresponding to ‘offset’
etypes relative to the current view
Parameters
offset (int)
Return type
int
Get_errhandler()
Get the error handler for a file
Return type
Errhandler
Get_group()
Return the group of processes that opened the file
Return type
Group
Get_info()
Return the hints for a file that that are currently in use
Return type
Info
Get_position()
Return the current position of the individual file pointer in etype units
relative to the current view
Return type
int
Get_position_shared()
Return the current position of the shared file pointer in etype units
relative to the current view
Return type
int
Get_size()
Return the file size
Return type
int
Get_type_extent(datatype)
Return the extent of datatype in the file
Parameters
datatype (Datatype)
Return type
int
Get_view()
Return the file view
Return type
Tuple[int, Datatype, Datatype, str]
Iread(buf)
Nonblocking read using individual file pointer
Parameters
buf (BufSpec)
Return type
Request
Iread_all(buf)
Nonblocking collective read using individual file pointer
Parameters
buf (BufSpec)
Return type
Request
Iread_at(offset, buf)
Nonblocking read using explicit offset
Parameters
• offset (int)
• buf (BufSpec)
Return type
Request
Iread_at_all(offset, buf)
Nonblocking collective read using explicit offset
Parameters
• offset (int)
• buf (BufSpec)
Return type
Request
Iread_shared(buf)
Nonblocking read using shared file pointer
Parameters
buf (BufSpec)
Return type
Request
Iwrite(buf)
Nonblocking write using individual file pointer
Parameters
buf (BufSpec)
Return type
Request
Iwrite_all(buf)
Nonblocking collective write using individual file pointer
Parameters
buf (BufSpec)
Return type
Request
Iwrite_at(offset, buf)
Nonblocking write using explicit offset
Parameters
• offset (int)
• buf (BufSpec)
Return type
Request
Iwrite_at_all(offset, buf)
Nonblocking collective write using explicit offset
Parameters
• offset (int)
• buf (BufSpec)
Return type
Request
Iwrite_shared(buf)
Nonblocking write using shared file pointer
Parameters
buf (BufSpec)
Return type
Request
classmethod Open(comm, filename, amode=MODE_RDONLY, info=INFO_NULL)
Open a file
Parameters
• comm (Intracomm)
• filename (str)
• amode (int)
• info (Info)
Return type
File
Preallocate(size)
Preallocate storage space for a file
Parameters
size (int)
Return type
None
Read(buf, status=None)
Read using individual file pointer
Parameters
• buf (BufSpec)
• status (Optional[Status])
Return type
None
Read_all(buf, status=None)
Collective read using individual file pointer
Parameters
• buf (BufSpec)
• status (Optional[Status])
Return type
None
Read_all_begin(buf)
Start a split collective read using individual file pointer
Parameters
buf (BufSpec)
Return type
None
Read_all_end(buf, status=None)
Complete a split collective read using individual file pointer
Parameters
• buf (BufSpec)
• status (Optional[Status])
Return type
None
Read_at(offset, buf, status=None)
Read using explicit offset
Parameters
• offset (int)
• buf (BufSpec)
• status (Optional[Status])
Return type
None
Read_at_all(offset, buf, status=None)
Collective read using explicit offset
Parameters
• offset (int)
• buf (BufSpec)
• status (Optional[Status])
Return type
None
Read_at_all_begin(offset, buf)
Start a split collective read using explict offset
Parameters
• offset (int)
• buf (BufSpec)
Return type
None
Read_at_all_end(buf, status=None)
Complete a split collective read using explict offset
Parameters
• buf (BufSpec)
• status (Optional[Status])
Return type
None
Read_ordered(buf, status=None)
Collective read using shared file pointer
Parameters
• buf (BufSpec)
• status (Optional[Status])
Return type
None
Read_ordered_begin(buf)
Start a split collective read using shared file pointer
Parameters
buf (BufSpec)
Return type
None
Read_ordered_end(buf, status=None)
Complete a split collective read using shared file pointer
Parameters
• buf (BufSpec)
• status (Optional[Status])
Return type
None
Read_shared(buf, status=None)
Read using shared file pointer
Parameters
• buf (BufSpec)
• status (Optional[Status])
Return type
None
Seek(offset, whence=SEEK_SET)
Update the individual file pointer
Parameters
• offset (int)
• whence (int)
Return type
None
Seek_shared(offset, whence=SEEK_SET)
Update the shared file pointer
Parameters
• offset (int)
• whence (int)
Return type
None
Set_atomicity(flag)
Set the atomicity mode
Parameters
flag (bool)
Return type
None
Set_errhandler(errhandler)
Set the error handler for a file
Parameters
errhandler (Errhandler)
Return type
None
Set_info(info)
Set new values for the hints associated with a file
Parameters
info (Info)
Return type
None
Set_size(size)
Sets the file size
Parameters
size (int)
Return type
None
Set_view(disp=0, etype=BYTE, filetype=None, datarep='native', info=INFO_NULL)
Set the file view
Parameters
• disp (int)
• etype (Datatype)
• filetype (Optional[Datatype])
• datarep (str)
• info (Info)
Return type
None
Sync() Causes all previous writes to be transferred to the storage device
Return type
None
Write(buf, status=None)
Write using individual file pointer
Parameters
• buf (BufSpec)
• status (Optional[Status])
Return type
None
Write_all(buf, status=None)
Collective write using individual file pointer
Parameters
• buf (BufSpec)
• status (Optional[Status])
Return type
None
Write_all_begin(buf)
Start a split collective write using individual file pointer
Parameters
buf (BufSpec)
Return type
None
Write_all_end(buf, status=None)
Complete a split collective write using individual file pointer
Parameters
• buf (BufSpec)
• status (Optional[Status])
Return type
None
Write_at(offset, buf, status=None)
Write using explicit offset
Parameters
• offset (int)
• buf (BufSpec)
• status (Optional[Status])
Return type
None
Write_at_all(offset, buf, status=None)
Collective write using explicit offset
Parameters
• offset (int)
• buf (BufSpec)
• status (Optional[Status])
Return type
None
Write_at_all_begin(offset, buf)
Start a split collective write using explict offset
Parameters
• offset (int)
• buf (BufSpec)
Return type
None
Write_at_all_end(buf, status=None)
Complete a split collective write using explict offset
Parameters
• buf (BufSpec)
• status (Optional[Status])
Return type
None
Write_ordered(buf, status=None)
Collective write using shared file pointer
Parameters
• buf (BufSpec)
• status (Optional[Status])
Return type
None
Write_ordered_begin(buf)
Start a split collective write using shared file pointer
Parameters
buf (BufSpec)
Return type
None
Write_ordered_end(buf, status=None)
Complete a split collective write using shared file pointer
Parameters
• buf (BufSpec)
• status (Optional[Status])
Return type
None
Write_shared(buf, status=None)
Write using shared file pointer
Parameters
• buf (BufSpec)
• status (Optional[Status])
Return type
None
classmethod f2py(arg)
Parameters
arg (int)
Return type
File
py2f()
Return type
int
Attributes Documentation
amode file access mode
atomicity
group file group
info file info
size file size
mpi4py.MPI.Graphcomm
class mpi4py.MPI.Graphcomm(comm=None)
Bases: Topocomm
General graph topology intracommunicator
Parameters
comm (Optional[Graphcomm])
Return type
Graphcomm
static __new__(cls, comm=None)
Parameters
comm (Optional[Graphcomm])
Return type
Graphcomm
Methods Summary
┌──────────────────────────┬──────────────────────────────────┐
│Get_dims() │ Return the number of nodes and │
│ │ edges │
├──────────────────────────┼──────────────────────────────────┤
│Get_neighbors(rank) │ Return list of neighbors of a │
│ │ process │
├──────────────────────────┼──────────────────────────────────┤
│Get_neighbors_count(rank) │ Return number of neighbors of a │
│ │ process │
├──────────────────────────┼──────────────────────────────────┤
│Get_topo() │ Return index and edges │
└──────────────────────────┴──────────────────────────────────┘
Attributes Summary
┌───────────┬───────────────────────────┐
│dims │ number of nodes and edges │
├───────────┼───────────────────────────┤
│edges │ │
├───────────┼───────────────────────────┤
│index │ │
├───────────┼───────────────────────────┤
│nedges │ number of edges │
├───────────┼───────────────────────────┤
│neighbors │ │
├───────────┼───────────────────────────┤
│nneighbors │ number of neighbors │
├───────────┼───────────────────────────┤
│nnodes │ number of nodes │
├───────────┼───────────────────────────┤
│topo │ topology information │
└───────────┴───────────────────────────┘
Methods Documentation
Get_dims()
Return the number of nodes and edges
Return type
Tuple[int, int]
Get_neighbors(rank)
Return list of neighbors of a process
Parameters
rank (int)
Return type
List[int]
Get_neighbors_count(rank)
Return number of neighbors of a process
Parameters
rank (int)
Return type
int
Get_topo()
Return index and edges
Return type
Tuple[List[int], List[int]]
Attributes Documentation
dims number of nodes and edges
edges
index
nedges number of edges
neighbors
nneighbors
number of neighbors
nnodes number of nodes
topo topology information
mpi4py.MPI.Grequest
class mpi4py.MPI.Grequest(request=None)
Bases: Request
Generalized request handle
Parameters
request (Optional[Grequest])
Return type
Grequest
static __new__(cls, request=None)
Parameters
request (Optional[Grequest])
Return type
Grequest
Methods Summary
┌─────────────────────────────────┬──────────────────────────────────┐
│Complete() │ Notify that a user-defined │
│ │ request is complete │
├─────────────────────────────────┼──────────────────────────────────┤
│Start(query_fn, free_fn, │ Create and return a user-defined │
│cancel_fn[, args, ...]) │ request │
└─────────────────────────────────┴──────────────────────────────────┘
Methods Documentation
Complete()
Notify that a user-defined request is complete
Return type
None
classmethod Start(query_fn, free_fn, cancel_fn, args=None, kargs=None)
Create and return a user-defined request
Parameters
• query_fn (Callable[..., None])
• free_fn (Callable[..., None])
• cancel_fn (Callable[..., None])
• args (Optional[Tuple[Any]])
• kargs (Optional[Dict[str, Any]])
Return type
Grequest
mpi4py.MPI.Group
class mpi4py.MPI.Group(group=None)
Bases: object
Group of processes
Parameters
group (Optional[Group])
Return type
Group
static __new__(cls, group=None)
Parameters
group (Optional[Group])
Return type
Group
Methods Summary
┌─────────────────────────────────┬──────────────────────────────────┐
│Compare(group1, group2) │ Compare two groups │
├─────────────────────────────────┼──────────────────────────────────┤
│Difference(group1, group2) │ Produce a group from the │
│ │ difference of two existing │
│ │ groups │
├─────────────────────────────────┼──────────────────────────────────┤
│Dup() │ Duplicate a group │
├─────────────────────────────────┼──────────────────────────────────┤
│Excl(ranks) │ Produce a group by reordering an │
│ │ existing group and taking only │
│ │ unlisted members │
├─────────────────────────────────┼──────────────────────────────────┤
│Free() │ Free a group │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_rank() │ Return the rank of this process │
│ │ in a group │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_size() │ Return the size of a group │
├─────────────────────────────────┼──────────────────────────────────┤
│Incl(ranks) │ Produce a group by reordering an │
│ │ existing group and taking only │
│ │ listed members │
├─────────────────────────────────┼──────────────────────────────────┤
│Intersection(group1, group2) │ Produce a group as the │
│ │ intersection of two existing │
│ │ groups │
├─────────────────────────────────┼──────────────────────────────────┤
│Range_excl(ranks) │ Create a new group by excluding │
│ │ ranges of processes from an │
│ │ existing group │
├─────────────────────────────────┼──────────────────────────────────┤
│Range_incl(ranks) │ Create a new group from ranges │
│ │ of of ranks in an existing group │
├─────────────────────────────────┼──────────────────────────────────┤
│Translate_ranks(group1, ranks1[, │ Translate the ranks of processes │
│group2]) │ in one group to those in another │
│ │ group │
├─────────────────────────────────┼──────────────────────────────────┤
│Union(group1, group2) │ Produce a group by combining two │
│ │ existing groups │
├─────────────────────────────────┼──────────────────────────────────┤
│f2py(arg) │ │
├─────────────────────────────────┼──────────────────────────────────┤
│py2f() │ │
└─────────────────────────────────┴──────────────────────────────────┘
Attributes Summary
┌─────┬───────────────────────────────┐
│rank │ rank of this process in group │
├─────┼───────────────────────────────┤
│size │ number of processes in group │
└─────┴───────────────────────────────┘
Methods Documentation
classmethod Compare(group1, group2)
Compare two groups
Parameters
• group1 (Group)
• group2 (Group)
Return type
int
classmethod Difference(group1, group2)
Produce a group from the difference of two existing groups
Parameters
• group1 (Group)
• group2 (Group)
Return type
Group
Dup() Duplicate a group
Return type
Group
Excl(ranks)
Produce a group by reordering an existing group and taking only unlisted
members
Parameters
ranks (Sequence[int])
Return type
Group
Free() Free a group
Return type
None
Get_rank()
Return the rank of this process in a group
Return type
int
Get_size()
Return the size of a group
Return type
int
Incl(ranks)
Produce a group by reordering an existing group and taking only listed
members
Parameters
ranks (Sequence[int])
Return type
Group
classmethod Intersection(group1, group2)
Produce a group as the intersection of two existing groups
Parameters
• group1 (Group)
• group2 (Group)
Return type
Group
Range_excl(ranks)
Create a new group by excluding ranges of processes from an existing group
Parameters
ranks (Sequence[Tuple[int, int, int]])
Return type
Group
Range_incl(ranks)
Create a new group from ranges of of ranks in an existing group
Parameters
ranks (Sequence[Tuple[int, int, int]])
Return type
Group
classmethod Translate_ranks(group1, ranks1, group2=None)
Translate the ranks of processes in one group to those in another group
Parameters
• group1 (Group)
• ranks1 (Sequence[int])
• group2 (Optional[Group])
Return type
List[int]
classmethod Union(group1, group2)
Produce a group by combining two existing groups
Parameters
• group1 (Group)
• group2 (Group)
Return type
Group
classmethod f2py(arg)
Parameters
arg (int)
Return type
Group
py2f()
Return type
int
Attributes Documentation
rank rank of this process in group
size number of processes in group
mpi4py.MPI.Info
class mpi4py.MPI.Info(info=None)
Bases: object
Info object
Parameters
info (Optional[Info])
Return type
Info
static __new__(cls, info=None)
Parameters
info (Optional[Info])
Return type
Info
Methods Summary
┌────────────────────┬──────────────────────────────────┐
│Create() │ Create a new, empty info object │
├────────────────────┼──────────────────────────────────┤
│Delete(key) │ Remove a (key, value) pair from │
│ │ info │
├────────────────────┼──────────────────────────────────┤
│Dup() │ Duplicate an existing info │
│ │ object, creating a new object, │
│ │ with the same (key, value) pairs │
│ │ and the same ordering of keys │
├────────────────────┼──────────────────────────────────┤
│Free() │ Free a info object │
├────────────────────┼──────────────────────────────────┤
│Get(key[, maxlen]) │ Retrieve the value associated │
│ │ with a key │
├────────────────────┼──────────────────────────────────┤
│Get_nkeys() │ Return the number of currently │
│ │ defined keys in info │
├────────────────────┼──────────────────────────────────┤
│Get_nthkey(n) │ Return the nth defined key in │
│ │ info. │
├────────────────────┼──────────────────────────────────┤
│Set(key, value) │ Add the (key, value) pair to │
│ │ info, and overrides the value if │
│ │ a value for the same key was │
│ │ previously set │
├────────────────────┼──────────────────────────────────┤
│clear() │ info clear │
├────────────────────┼──────────────────────────────────┤
│copy() │ info copy │
├────────────────────┼──────────────────────────────────┤
│f2py(arg) │ │
├────────────────────┼──────────────────────────────────┤
│get(key[, default]) │ info get │
├────────────────────┼──────────────────────────────────┤
│items() │ info items │
├────────────────────┼──────────────────────────────────┤
│keys() │ info keys │
├────────────────────┼──────────────────────────────────┤
│pop(key, *default) │ info pop │
├────────────────────┼──────────────────────────────────┤
│popitem() │ info popitem │
├────────────────────┼──────────────────────────────────┤
│py2f() │ │
├────────────────────┼──────────────────────────────────┤
│update([other]) │ info update │
├────────────────────┼──────────────────────────────────┤
│values() │ info values │
└────────────────────┴──────────────────────────────────┘
Methods Documentation
classmethod Create()
Create a new, empty info object
Return type
Info
Delete(key)
Remove a (key, value) pair from info
Parameters
key (str)
Return type
None
Dup() Duplicate an existing info object, creating a new object, with the same
(key, value) pairs and the same ordering of keys
Return type
Info
Free() Free a info object
Return type
None
Get(key, maxlen=-1)
Retrieve the value associated with a key
Parameters
• key (str)
• maxlen (int)
Return type
Optional[str]
Get_nkeys()
Return the number of currently defined keys in info
Return type
int
Get_nthkey(n)
Return the nth defined key in info. Keys are numbered in the range [0, N)
where N is the value returned by Info.Get_nkeys()
Parameters
n (int)
Return type
str
Set(key, value)
Add the (key, value) pair to info, and overrides the value if a value for
the same key was previously set
Parameters
• key (str)
• value (str)
Return type
None
clear()
info clear
Return type
None
copy() info copy
Return type
Info
classmethod f2py(arg)
Parameters
arg (int)
Return type
Info
get(key, default=None)
info get
Parameters
• key (str)
• default (Optional[str])
Return type
Optional[str]
items()
info items
Return type
List[Tuple[str, str]]
keys() info keys
Return type
List[str]
pop(key, *default)
info pop
Parameters
• key (str)
• default (str)
Return type
str
popitem()
info popitem
Return type
Tuple[str, str]
py2f()
Return type
int
update(other=(), **kwds)
info update
Parameters
• other (Union[Info, Mapping[str, str], Iterable[Tuple[str, str]]])
• kwds (str)
Return type
None
values()
info values
Return type
List[str]
mpi4py.MPI.Intercomm
class mpi4py.MPI.Intercomm(comm=None)
Bases: Comm
Intercommunicator
Parameters
comm (Optional[Intercomm])
Return type
Intercomm
static __new__(cls, comm=None)
Parameters
comm (Optional[Intercomm])
Return type
Intercomm
Methods Summary
┌───────────────────┬──────────────────────────────────┐
│Get_remote_group() │ Access the remote group │
│ │ associated with the │
│ │ inter-communicator │
├───────────────────┼──────────────────────────────────┤
│Get_remote_size() │ Intercommunicator remote size │
├───────────────────┼──────────────────────────────────┤
│Merge([high]) │ Merge intercommunicator │
└───────────────────┴──────────────────────────────────┘
Attributes Summary
┌─────────────┬────────────────────────────┐
│remote_group │ remote group │
├─────────────┼────────────────────────────┤
│remote_size │ number of remote processes │
└─────────────┴────────────────────────────┘
Methods Documentation
Get_remote_group()
Access the remote group associated with the inter-communicator
Return type
Group
Get_remote_size()
Intercommunicator remote size
Return type
int
Merge(high=False)
Merge intercommunicator
Parameters
high (bool)
Return type
Intracomm
Attributes Documentation
remote_group
remote group
remote_size
number of remote processes
mpi4py.MPI.Intracomm
class mpi4py.MPI.Intracomm(comm=None)
Bases: Comm
Intracommunicator
Parameters
comm (Optional[Intracomm])
Return type
Intracomm
static __new__(cls, comm=None)
Parameters
comm (Optional[Intracomm])
Return type
Intracomm
Methods Summary
┌────────────────────────────────────┬──────────────────────────────────┐
│Accept(port_name[, info, root]) │ Accept a request to form a new │
│ │ intercommunicator │
├────────────────────────────────────┼──────────────────────────────────┤
│Cart_map(dims[, periods]) │ Return an optimal placement for │
│ │ the calling process on the │
│ │ physical machine │
├────────────────────────────────────┼──────────────────────────────────┤
│Connect(port_name[, info, root]) │ Make a request to form a new │
│ │ intercommunicator │
├────────────────────────────────────┼──────────────────────────────────┤
│Create_cart(dims[, periods, │ Create cartesian communicator │
│reorder]) │ │
├────────────────────────────────────┼──────────────────────────────────┤
│Create_dist_graph(sources, │ Create distributed graph │
│degrees, destinations) │ communicator │
├────────────────────────────────────┼──────────────────────────────────┤
│Create_dist_graph_adjacent(sources, │ Create distributed graph │
│destinations) │ communicator │
├────────────────────────────────────┼──────────────────────────────────┤
│Create_graph(index, edges[, │ Create graph communicator │
│reorder]) │ │
├────────────────────────────────────┼──────────────────────────────────┤
│Create_intercomm(local_leader, │ Create intercommunicator │
│peer_comm, ...) │ │
├────────────────────────────────────┼──────────────────────────────────┤
│Exscan(sendbuf, recvbuf[, op]) │ Exclusive Scan │
├────────────────────────────────────┼──────────────────────────────────┤
│Graph_map(index, edges) │ Return an optimal placement for │
│ │ the calling process on the │
│ │ physical machine │
├────────────────────────────────────┼──────────────────────────────────┤
│Iexscan(sendbuf, recvbuf[, op]) │ Inclusive Scan │
├────────────────────────────────────┼──────────────────────────────────┤
│Iscan(sendbuf, recvbuf[, op]) │ Inclusive Scan │
├────────────────────────────────────┼──────────────────────────────────┤
│Scan(sendbuf, recvbuf[, op]) │ Inclusive Scan │
├────────────────────────────────────┼──────────────────────────────────┤
│Spawn(command[, args, maxprocs, │ Spawn instances of a single MPI │
│info, root, ...]) │ application │
├────────────────────────────────────┼──────────────────────────────────┤
│Spawn_multiple(command[, args, │ Spawn instances of multiple MPI │
│maxprocs, ...]) │ applications │
├────────────────────────────────────┼──────────────────────────────────┤
│exscan(sendobj[, op]) │ Exclusive Scan │
├────────────────────────────────────┼──────────────────────────────────┤
│scan(sendobj[, op]) │ Inclusive Scan │
└────────────────────────────────────┴──────────────────────────────────┘
Methods Documentation
Accept(port_name, info=INFO_NULL, root=0)
Accept a request to form a new intercommunicator
Parameters
• port_name (str)
• info (Info)
• root (int)
Return type
Intercomm
Cart_map(dims, periods=None)
Return an optimal placement for the calling process on the physical machine
Parameters
• dims (Sequence[int])
• periods (Optional[Sequence[bool]])
Return type
int
Connect(port_name, info=INFO_NULL, root=0)
Make a request to form a new intercommunicator
Parameters
• port_name (str)
• info (Info)
• root (int)
Return type
Intercomm
Create_cart(dims, periods=None, reorder=False)
Create cartesian communicator
Parameters
• dims (Sequence[int])
• periods (Optional[Sequence[bool]])
• reorder (bool)
Return type
Cartcomm
Create_dist_graph(sources, degrees, destinations, weights=None, info=INFO_NULL,
reorder=False)
Create distributed graph communicator
Parameters
• sources (Sequence[int])
• degrees (Sequence[int])
• destinations (Sequence[int])
• weights (Optional[Sequence[int]])
• info (Info)
• reorder (bool)
Return type
Distgraphcomm
Create_dist_graph_adjacent(sources, destinations, sourceweights=None,
destweights=None, info=INFO_NULL, reorder=False)
Create distributed graph communicator
Parameters
• sources (Sequence[int])
• destinations (Sequence[int])
• sourceweights (Optional[Sequence[int]])
• destweights (Optional[Sequence[int]])
• info (Info)
• reorder (bool)
Return type
Distgraphcomm
Create_graph(index, edges, reorder=False)
Create graph communicator
Parameters
• index (Sequence[int])
• edges (Sequence[int])
• reorder (bool)
Return type
Graphcomm
Create_intercomm(local_leader, peer_comm, remote_leader, tag=0)
Create intercommunicator
Parameters
• local_leader (int)
• peer_comm (Intracomm)
• remote_leader (int)
• tag (int)
Return type
Intercomm
Exscan(sendbuf, recvbuf, op=SUM)
Exclusive Scan
Parameters
• sendbuf (Union[BufSpec, InPlace])
• recvbuf (BufSpec)
• op (Op)
Return type
None
Graph_map(index, edges)
Return an optimal placement for the calling process on the physical machine
Parameters
• index (Sequence[int])
• edges (Sequence[int])
Return type
int
Iexscan(sendbuf, recvbuf, op=SUM)
Inclusive Scan
Parameters
• sendbuf (Union[BufSpec, InPlace])
• recvbuf (BufSpec)
• op (Op)
Return type
Request
Iscan(sendbuf, recvbuf, op=SUM)
Inclusive Scan
Parameters
• sendbuf (Union[BufSpec, InPlace])
• recvbuf (BufSpec)
• op (Op)
Return type
Request
Scan(sendbuf, recvbuf, op=SUM)
Inclusive Scan
Parameters
• sendbuf (Union[BufSpec, InPlace])
• recvbuf (BufSpec)
• op (Op)
Return type
None
Spawn(command, args=None, maxprocs=1, info=INFO_NULL, root=0, errcodes=None)
Spawn instances of a single MPI application
Parameters
• command (str)
• args (Optional[Sequence[str]])
• maxprocs (int)
• info (Info)
• root (int)
• errcodes (Optional[list])
Return type
Intercomm
Spawn_multiple(command, args=None, maxprocs=None, info=INFO_NULL, root=0,
errcodes=None)
Spawn instances of multiple MPI applications
Parameters
• command (Sequence[str])
• args (Optional[Sequence[Sequence[str]]])
• maxprocs (Optional[Sequence[int]])
• info (Union[Info, Sequence[Info]])
• root (int)
• errcodes (Optional[list])
Return type
Intercomm
exscan(sendobj, op=SUM)
Exclusive Scan
Parameters
• sendobj (Any)
• op (Union[Op, Callable[[Any, Any], Any]])
Return type
Any
scan(sendobj, op=SUM)
Inclusive Scan
Parameters
• sendobj (Any)
• op (Union[Op, Callable[[Any, Any], Any]])
Return type
Any
mpi4py.MPI.Message
class mpi4py.MPI.Message(message=None)
Bases: object
Matched message handle
Parameters
message (Optional[Message])
Return type
Message
static __new__(cls, message=None)
Parameters
message (Optional[Message])
Return type
Message
Methods Summary
┌─────────────────────────────────┬──────────────────────────────────┐
│Iprobe(comm[, source, tag, │ Nonblocking test for a matched │
│status]) │ message │
├─────────────────────────────────┼──────────────────────────────────┤
│Irecv(buf) │ Nonblocking receive of matched │
│ │ message │
├─────────────────────────────────┼──────────────────────────────────┤
│Probe(comm[, source, tag, │ Blocking test for a matched │
│status]) │ message │
├─────────────────────────────────┼──────────────────────────────────┤
│Recv(buf[, status]) │ Blocking receive of matched │
│ │ message │
├─────────────────────────────────┼──────────────────────────────────┤
│f2py(arg) │ │
├─────────────────────────────────┼──────────────────────────────────┤
│iprobe(comm[, source, tag, │ Nonblocking test for a matched │
│status]) │ message │
├─────────────────────────────────┼──────────────────────────────────┤
│irecv() │ Nonblocking receive of matched │
│ │ message │
├─────────────────────────────────┼──────────────────────────────────┤
│probe(comm[, source, tag, │ Blocking test for a matched │
│status]) │ message │
├─────────────────────────────────┼──────────────────────────────────┤
│py2f() │ │
├─────────────────────────────────┼──────────────────────────────────┤
│recv([status]) │ Blocking receive of matched │
│ │ message │
└─────────────────────────────────┴──────────────────────────────────┘
Methods Documentation
classmethod Iprobe(comm, source=ANY_SOURCE, tag=ANY_TAG, status=None)
Nonblocking test for a matched message
Parameters
• comm (Comm)
• source (int)
• tag (int)
• status (Optional[Status])
Return type
Optional[Message]
Irecv(buf)
Nonblocking receive of matched message
Parameters
buf (BufSpec)
Return type
Request
classmethod Probe(comm, source=ANY_SOURCE, tag=ANY_TAG, status=None)
Blocking test for a matched message
Parameters
• comm (Comm)
• source (int)
• tag (int)
• status (Optional[Status])
Return type
Message
Recv(buf, status=None)
Blocking receive of matched message
Parameters
• buf (BufSpec)
• status (Optional[Status])
Return type
None
classmethod f2py(arg)
Parameters
arg (int)
Return type
Message
classmethod iprobe(comm, source=ANY_SOURCE, tag=ANY_TAG, status=None)
Nonblocking test for a matched message
Parameters
• comm (Comm)
• source (int)
• tag (int)
• status (Optional[Status])
Return type
Optional[Message]
irecv()
Nonblocking receive of matched message
Return type
Request
classmethod probe(comm, source=ANY_SOURCE, tag=ANY_TAG, status=None)
Blocking test for a matched message
Parameters
• comm (Comm)
• source (int)
• tag (int)
• status (Optional[Status])
Return type
Message
py2f()
Return type
int
recv(status=None)
Blocking receive of matched message
Parameters
status (Optional[Status])
Return type
Any
mpi4py.MPI.Op
class mpi4py.MPI.Op(op=None)
Bases: object
Operation object
Parameters
op (Optional[Op])
Return type
Op
static __new__(cls, op=None)
Parameters
op (Optional[Op])
Return type
Op
Methods Summary
┌──────────────────────────────┬──────────────────────────────────┐
│Create(function[, commute]) │ Create a user-defined operation │
├──────────────────────────────┼──────────────────────────────────┤
│Free() │ Free the operation │
├──────────────────────────────┼──────────────────────────────────┤
│Is_commutative() │ Query reduction operations for │
│ │ their commutativity │
├──────────────────────────────┼──────────────────────────────────┤
│Reduce_local(inbuf, inoutbuf) │ Apply a reduction operator to │
│ │ local data │
├──────────────────────────────┼──────────────────────────────────┤
│f2py(arg) │ │
├──────────────────────────────┼──────────────────────────────────┤
│py2f() │ │
└──────────────────────────────┴──────────────────────────────────┘
Attributes Summary
┌───────────────┬───────────────────────────┐
│is_commutative │ is commutative │
├───────────────┼───────────────────────────┤
│is_predefined │ is a predefined operation │
└───────────────┴───────────────────────────┘
Methods Documentation
classmethod Create(function, commute=False)
Create a user-defined operation
Parameters
• function (Callable[[Buffer, Buffer, Datatype], None])
• commute (bool)
Return type
Op
Free() Free the operation
Return type
None
Is_commutative()
Query reduction operations for their commutativity
Return type
bool
Reduce_local(inbuf, inoutbuf)
Apply a reduction operator to local data
Parameters
• inbuf (BufSpec)
• inoutbuf (BufSpec)
Return type
None
classmethod f2py(arg)
Parameters
arg (int)
Return type
Op
py2f()
Return type
int
Attributes Documentation
is_commutative
is commutative
is_predefined
is a predefined operation
mpi4py.MPI.Pickle
class mpi4py.MPI.Pickle(dumps=None, loads=None, protocol=None)
Bases: object
Pickle/unpickle Python objects
Parameters
• dumps (Optional[Callable[[Any, int], bytes]])
• loads (Optional[Callable[[Buffer], Any]])
• protocol (Optional[int])
__init__(dumps=None, loads=None, protocol=None)
Parameters
• dumps (Optional[Callable[[Any, int], bytes]])
• loads (Optional[Callable[[Buffer], Any]])
• protocol (Optional[int])
Return type
None
Methods Summary
┌──────────────────────────────┬──────────────────────────────────┐
│dumps(obj[, buffer_callback]) │ Serialize object to pickle data │
│ │ stream. │
├──────────────────────────────┼──────────────────────────────────┤
│loads(data[, buffers]) │ Deserialize object from pickle │
│ │ data stream. │
└──────────────────────────────┴──────────────────────────────────┘
Attributes Summary
┌─────────┬─────────────────┐
│PROTOCOL │ pickle protocol │
└─────────┴─────────────────┘
Methods Documentation
dumps(obj, buffer_callback=None)
Serialize object to pickle data stream.
Parameters
• obj (Any)
• buffer_callback (Optional[Callable[[Buffer], Any]])
Return type
bytes
loads(data, buffers=None)
Deserialize object from pickle data stream.
Parameters
• data (Buffer)
• buffers (Optional[Iterable[Buffer]])
Return type
Any
Attributes Documentation
PROTOCOL
pickle protocol
mpi4py.MPI.Prequest
class mpi4py.MPI.Prequest(request=None)
Bases: Request
Persistent request handle
Parameters
request (Optional[Prequest])
Return type
Prequest
static __new__(cls, request=None)
Parameters
request (Optional[Prequest])
Return type
Prequest
Methods Summary
┌───────────────────┬──────────────────────────────────┐
│Start() │ Initiate a communication with a │
│ │ persistent request │
├───────────────────┼──────────────────────────────────┤
│Startall(requests) │ Start a collection of persistent │
│ │ requests │
└───────────────────┴──────────────────────────────────┘
Methods Documentation
Start()
Initiate a communication with a persistent request
Return type
None
classmethod Startall(requests)
Start a collection of persistent requests
Parameters
requests (List[Prequest])
Return type
None
mpi4py.MPI.Request
class mpi4py.MPI.Request(request=None)
Bases: object
Request handle
Parameters
request (Optional[Request])
Return type
Request
static __new__(cls, request=None)
Parameters
request (Optional[Request])
Return type
Request
Methods Summary
┌───────────────────────────────┬──────────────────────────────────┐
│Cancel() │ Cancel a communication request │
├───────────────────────────────┼──────────────────────────────────┤
│Free() │ Free a communication request │
├───────────────────────────────┼──────────────────────────────────┤
│Get_status([status]) │ Non-destructive test for the │
│ │ completion of a request │
├───────────────────────────────┼──────────────────────────────────┤
│Test([status]) │ Test for the completion of a │
│ │ send or receive │
├───────────────────────────────┼──────────────────────────────────┤
│Testall(requests[, statuses]) │ Test for completion of all │
│ │ previously initiated requests │
├───────────────────────────────┼──────────────────────────────────┤
│Testany(requests[, status]) │ Test for completion of any │
│ │ previously initiated request │
├───────────────────────────────┼──────────────────────────────────┤
│Testsome(requests[, statuses]) │ Test for completion of some │
│ │ previously initiated requests │
├───────────────────────────────┼──────────────────────────────────┤
│Wait([status]) │ Wait for a send or receive to │
│ │ complete │
├───────────────────────────────┼──────────────────────────────────┤
│Waitall(requests[, statuses]) │ Wait for all previously │
│ │ initiated requests to complete │
├───────────────────────────────┼──────────────────────────────────┤
│Waitany(requests[, status]) │ Wait for any previously │
│ │ initiated request to complete │
├───────────────────────────────┼──────────────────────────────────┤
│Waitsome(requests[, statuses]) │ Wait for some previously │
│ │ initiated requests to complete │
├───────────────────────────────┼──────────────────────────────────┤
│cancel() │ Cancel a communication request │
├───────────────────────────────┼──────────────────────────────────┤
│f2py(arg) │ │
├───────────────────────────────┼──────────────────────────────────┤
│get_status([status]) │ Non-destructive test for the │
│ │ completion of a request │
├───────────────────────────────┼──────────────────────────────────┤
│py2f() │ │
├───────────────────────────────┼──────────────────────────────────┤
│test([status]) │ Test for the completion of a │
│ │ send or receive │
├───────────────────────────────┼──────────────────────────────────┤
│testall(requests[, statuses]) │ Test for completion of all │
│ │ previously initiated requests │
├───────────────────────────────┼──────────────────────────────────┤
│testany(requests[, status]) │ Test for completion of any │
│ │ previously initiated request │
├───────────────────────────────┼──────────────────────────────────┤
│testsome(requests[, statuses]) │ Test for completion of some │
│ │ previously initiated requests │
├───────────────────────────────┼──────────────────────────────────┤
│wait([status]) │ Wait for a send or receive to │
│ │ complete │
├───────────────────────────────┼──────────────────────────────────┤
│waitall(requests[, statuses]) │ Wait for all previously │
│ │ initiated requests to complete │
├───────────────────────────────┼──────────────────────────────────┤
│waitany(requests[, status]) │ Wait for any previously │
│ │ initiated request to complete │
├───────────────────────────────┼──────────────────────────────────┤
│waitsome(requests[, statuses]) │ Wait for some previously │
│ │ initiated requests to complete │
└───────────────────────────────┴──────────────────────────────────┘
Methods Documentation
Cancel()
Cancel a communication request
Return type
None
Free() Free a communication request
Return type
None
Get_status(status=None)
Non-destructive test for the completion of a request
Parameters
status (Optional[Status])
Return type
bool
Test(status=None)
Test for the completion of a send or receive
Parameters
status (Optional[Status])
Return type
bool
classmethod Testall(requests, statuses=None)
Test for completion of all previously initiated requests
Parameters
• requests (Sequence[Request])
• statuses (Optional[List[Status]])
Return type
bool
classmethod Testany(requests, status=None)
Test for completion of any previously initiated request
Parameters
• requests (Sequence[Request])
• status (Optional[Status])
Return type
Tuple[int, bool]
classmethod Testsome(requests, statuses=None)
Test for completion of some previously initiated requests
Parameters
• requests (Sequence[Request])
• statuses (Optional[List[Status]])
Return type
Optional[List[int]]
Wait(status=None)
Wait for a send or receive to complete
Parameters
status (Optional[Status])
Return type
Literal[True]
classmethod Waitall(requests, statuses=None)
Wait for all previously initiated requests to complete
Parameters
• requests (Sequence[Request])
• statuses (Optional[List[Status]])
Return type
Literal[True]
classmethod Waitany(requests, status=None)
Wait for any previously initiated request to complete
Parameters
• requests (Sequence[Request])
• status (Optional[Status])
Return type
int
classmethod Waitsome(requests, statuses=None)
Wait for some previously initiated requests to complete
Parameters
• requests (Sequence[Request])
• statuses (Optional[List[Status]])
Return type
Optional[List[int]]
cancel()
Cancel a communication request
Return type
None
classmethod f2py(arg)
Parameters
arg (int)
Return type
Request
get_status(status=None)
Non-destructive test for the completion of a request
Parameters
status (Optional[Status])
Return type
bool
py2f()
Return type
int
test(status=None)
Test for the completion of a send or receive
Parameters
status (Optional[Status])
Return type
Tuple[bool, Optional[Any]]
classmethod testall(requests, statuses=None)
Test for completion of all previously initiated requests
Parameters
• requests (Sequence[Request])
• statuses (Optional[List[Status]])
Return type
Tuple[bool, Optional[List[Any]]]
classmethod testany(requests, status=None)
Test for completion of any previously initiated request
Parameters
• requests (Sequence[Request])
• status (Optional[Status])
Return type
Tuple[int, bool, Optional[Any]]
classmethod testsome(requests, statuses=None)
Test for completion of some previously initiated requests
Parameters
• requests (Sequence[Request])
• statuses (Optional[List[Status]])
Return type
Tuple[Optional[List[int]], Optional[List[Any]]]
wait(status=None)
Wait for a send or receive to complete
Parameters
status (Optional[Status])
Return type
Any
classmethod waitall(requests, statuses=None)
Wait for all previously initiated requests to complete
Parameters
• requests (Sequence[Request])
• statuses (Optional[List[Status]])
Return type
List[Any]
classmethod waitany(requests, status=None)
Wait for any previously initiated request to complete
Parameters
• requests (Sequence[Request])
• status (Optional[Status])
Return type
Tuple[int, Any]
classmethod waitsome(requests, statuses=None)
Wait for some previously initiated requests to complete
Parameters
• requests (Sequence[Request])
• statuses (Optional[List[Status]])
Return type
Tuple[Optional[List[int]], Optional[List[Any]]]
mpi4py.MPI.Status
class mpi4py.MPI.Status(status=None)
Bases: object
Status object
Parameters
status (Optional[Status])
Return type
Status
static __new__(cls, status=None)
Parameters
status (Optional[Status])
Return type
Status
Methods Summary
┌──────────────────────────────┬──────────────────────────────────┐
│Get_count([datatype]) │ Get the number of top level │
│ │ elements │
├──────────────────────────────┼──────────────────────────────────┤
│Get_elements(datatype) │ Get the number of basic elements │
│ │ in a datatype │
├──────────────────────────────┼──────────────────────────────────┤
│Get_error() │ Get message error │
├──────────────────────────────┼──────────────────────────────────┤
│Get_source() │ Get message source │
├──────────────────────────────┼──────────────────────────────────┤
│Get_tag() │ Get message tag │
├──────────────────────────────┼──────────────────────────────────┤
│Is_cancelled() │ Test to see if a request was │
│ │ cancelled │
├──────────────────────────────┼──────────────────────────────────┤
│Set_cancelled(flag) │ Set the cancelled state │
│ │ associated with a status │
├──────────────────────────────┼──────────────────────────────────┤
│Set_elements(datatype, count) │ Set the number of elements in a │
│ │ status │
├──────────────────────────────┼──────────────────────────────────┤
│Set_error(error) │ Set message error │
├──────────────────────────────┼──────────────────────────────────┤
│Set_source(source) │ Set message source │
├──────────────────────────────┼──────────────────────────────────┤
│Set_tag(tag) │ Set message tag │
├──────────────────────────────┼──────────────────────────────────┤
│f2py(arg) │ │
├──────────────────────────────┼──────────────────────────────────┤
│py2f() │ │
└──────────────────────────────┴──────────────────────────────────┘
Attributes Summary
┌──────────┬─────────────────┐
│cancelled │ cancelled state │
├──────────┼─────────────────┤
│count │ byte count │
├──────────┼─────────────────┤
│error │ │
├──────────┼─────────────────┤
│source │ │
├──────────┼─────────────────┤
│tag │ │
└──────────┴─────────────────┘
Methods Documentation
Get_count(datatype=BYTE)
Get the number of top level elements
Parameters
datatype (Datatype)
Return type
int
Get_elements(datatype)
Get the number of basic elements in a datatype
Parameters
datatype (Datatype)
Return type
int
Get_error()
Get message error
Return type
int
Get_source()
Get message source
Return type
int
Get_tag()
Get message tag
Return type
int
Is_cancelled()
Test to see if a request was cancelled
Return type
bool
Set_cancelled(flag)
Set the cancelled state associated with a status
NOTE:
This should be only used when implementing query callback functions for
generalized requests
Parameters
flag (bool)
Return type
None
Set_elements(datatype, count)
Set the number of elements in a status
NOTE:
This should be only used when implementing query callback functions for
generalized requests
Parameters
• datatype (Datatype)
• count (int)
Return type
None
Set_error(error)
Set message error
Parameters
error (int)
Return type
None
Set_source(source)
Set message source
Parameters
source (int)
Return type
None
Set_tag(tag)
Set message tag
Parameters
tag (int)
Return type
None
classmethod f2py(arg)
Parameters
arg (List[int])
Return type
Status
py2f()
Return type
List[int]
Attributes Documentation
cancelled
cancelled state
count byte count
error
source
tag
mpi4py.MPI.Topocomm
class mpi4py.MPI.Topocomm(comm=None)
Bases: Intracomm
Topology intracommunicator
Parameters
comm (Optional[Topocomm])
Return type
Topocomm
static __new__(cls, comm=None)
Parameters
comm (Optional[Topocomm])
Return type
Topocomm
Methods Summary
┌──────────────────────────────┬──────────────────────────────────┐
│Ineighbor_allgather(sendbuf, │ Nonblocking Neighbor Gather to │
│recvbuf) │ All │
├──────────────────────────────┼──────────────────────────────────┤
│Ineighbor_allgatherv(sendbuf, │ Nonblocking Neighbor Gather to │
│recvbuf) │ All Vector │
├──────────────────────────────┼──────────────────────────────────┤
│Ineighbor_alltoall(sendbuf, │ Nonblocking Neighbor All-to-All │
│recvbuf) │ │
├──────────────────────────────┼──────────────────────────────────┤
│Ineighbor_alltoallv(sendbuf, │ Nonblocking Neighbor All-to-All │
│recvbuf) │ Vector │
├──────────────────────────────┼──────────────────────────────────┤
│Ineighbor_alltoallw(sendbuf, │ Nonblocking Neighbor All-to-All │
│recvbuf) │ Generalized │
├──────────────────────────────┼──────────────────────────────────┤
│Neighbor_allgather(sendbuf, │ Neighbor Gather to All │
│recvbuf) │ │
├──────────────────────────────┼──────────────────────────────────┤
│Neighbor_allgatherv(sendbuf, │ Neighbor Gather to All Vector │
│recvbuf) │ │
├──────────────────────────────┼──────────────────────────────────┤
│Neighbor_alltoall(sendbuf, │ Neighbor All-to-All │
│recvbuf) │ │
├──────────────────────────────┼──────────────────────────────────┤
│Neighbor_alltoallv(sendbuf, │ Neighbor All-to-All Vector │
│recvbuf) │ │
├──────────────────────────────┼──────────────────────────────────┤
│Neighbor_alltoallw(sendbuf, │ Neighbor All-to-All Generalized │
│recvbuf) │ │
├──────────────────────────────┼──────────────────────────────────┤
│neighbor_allgather(sendobj) │ Neighbor Gather to All │
├──────────────────────────────┼──────────────────────────────────┤
│neighbor_alltoall(sendobj) │ Neighbor All to All │
│ │ Scatter/Gather │
└──────────────────────────────┴──────────────────────────────────┘
Attributes Summary
┌───────────┬──────────────────────────────────┐
│degrees │ number of incoming and outgoing │
│ │ neighbors │
├───────────┼──────────────────────────────────┤
│indegree │ number of incoming neighbors │
├───────────┼──────────────────────────────────┤
│inedges │ incoming neighbors │
├───────────┼──────────────────────────────────┤
│inoutedges │ incoming and outgoing neighbors │
├───────────┼──────────────────────────────────┤
│outdegree │ number of outgoing neighbors │
├───────────┼──────────────────────────────────┤
│outedges │ outgoing neighbors │
└───────────┴──────────────────────────────────┘
Methods Documentation
Ineighbor_allgather(sendbuf, recvbuf)
Nonblocking Neighbor Gather to All
Parameters
• sendbuf (BufSpec)
• recvbuf (BufSpecB)
Return type
Request
Ineighbor_allgatherv(sendbuf, recvbuf)
Nonblocking Neighbor Gather to All Vector
Parameters
• sendbuf (BufSpec)
• recvbuf (BufSpecV)
Return type
Request
Ineighbor_alltoall(sendbuf, recvbuf)
Nonblocking Neighbor All-to-All
Parameters
• sendbuf (BufSpecB)
• recvbuf (BufSpecB)
Return type
Request
Ineighbor_alltoallv(sendbuf, recvbuf)
Nonblocking Neighbor All-to-All Vector
Parameters
• sendbuf (BufSpecV)
• recvbuf (BufSpecV)
Return type
Request
Ineighbor_alltoallw(sendbuf, recvbuf)
Nonblocking Neighbor All-to-All Generalized
Parameters
• sendbuf (BufSpecW)
• recvbuf (BufSpecW)
Return type
Request
Neighbor_allgather(sendbuf, recvbuf)
Neighbor Gather to All
Parameters
• sendbuf (BufSpec)
• recvbuf (BufSpecB)
Return type
None
Neighbor_allgatherv(sendbuf, recvbuf)
Neighbor Gather to All Vector
Parameters
• sendbuf (BufSpec)
• recvbuf (BufSpecV)
Return type
None
Neighbor_alltoall(sendbuf, recvbuf)
Neighbor All-to-All
Parameters
• sendbuf (BufSpecB)
• recvbuf (BufSpecB)
Return type
None
Neighbor_alltoallv(sendbuf, recvbuf)
Neighbor All-to-All Vector
Parameters
• sendbuf (BufSpecV)
• recvbuf (BufSpecV)
Return type
None
Neighbor_alltoallw(sendbuf, recvbuf)
Neighbor All-to-All Generalized
Parameters
• sendbuf (BufSpecW)
• recvbuf (BufSpecW)
Return type
None
neighbor_allgather(sendobj)
Neighbor Gather to All
Parameters
sendobj (Any)
Return type
List[Any]
neighbor_alltoall(sendobj)
Neighbor All to All Scatter/Gather
Parameters
sendobj (List[Any])
Return type
List[Any]
Attributes Documentation
degrees
number of incoming and outgoing neighbors
indegree
number of incoming neighbors
inedges
incoming neighbors
inoutedges
incoming and outgoing neighbors
outdegree
number of outgoing neighbors
outedges
outgoing neighbors
mpi4py.MPI.Win
class mpi4py.MPI.Win(win=None)
Bases: object
Window handle
Parameters
win (Optional[Win])
Return type
Win
static __new__(cls, win=None)
Parameters
win (Optional[Win])
Return type
Win
Methods Summary
┌─────────────────────────────────┬──────────────────────────────────┐
│Accumulate(origin, target_rank[, │ Accumulate data into the target │
│target, op]) │ process │
├─────────────────────────────────┼──────────────────────────────────┤
│Allocate(size[, disp_unit, info, │ Create an window object for │
│comm]) │ one-sided communication │
├─────────────────────────────────┼──────────────────────────────────┤
│Allocate_shared(size[, │ Create an window object for │
│disp_unit, info, comm]) │ one-sided communication │
├─────────────────────────────────┼──────────────────────────────────┤
│Attach(memory) │ Attach a local memory region │
├─────────────────────────────────┼──────────────────────────────────┤
│Call_errhandler(errorcode) │ Call the error handler installed │
│ │ on a window │
├─────────────────────────────────┼──────────────────────────────────┤
│Compare_and_swap(origin, │ Perform one-sided atomic │
│compare, result, ...) │ compare-and-swap │
├─────────────────────────────────┼──────────────────────────────────┤
│Complete() │ Completes an RMA operations │
│ │ begun after an Win.Start() │
├─────────────────────────────────┼──────────────────────────────────┤
│Create(memory[, disp_unit, info, │ Create an window object for │
│comm]) │ one-sided communication │
├─────────────────────────────────┼──────────────────────────────────┤
│Create_dynamic([info, comm]) │ Create an window object for │
│ │ one-sided communication │
├─────────────────────────────────┼──────────────────────────────────┤
│Create_keyval([copy_fn, │ Create a new attribute key for │
│delete_fn, nopython]) │ windows │
├─────────────────────────────────┼──────────────────────────────────┤
│Delete_attr(keyval) │ Delete attribute value │
│ │ associated with a key │
├─────────────────────────────────┼──────────────────────────────────┤
│Detach(memory) │ Detach a local memory region │
├─────────────────────────────────┼──────────────────────────────────┤
│Fence([assertion]) │ Perform an MPI fence │
│ │ synchronization on a window │
├─────────────────────────────────┼──────────────────────────────────┤
│Fetch_and_op(origin, result, │ Perform one-sided │
│target_rank[, ...]) │ read-modify-write │
├─────────────────────────────────┼──────────────────────────────────┤
│Flush(rank) │ Complete all outstanding RMA │
│ │ operations at the given target │
├─────────────────────────────────┼──────────────────────────────────┤
│Flush_all() │ Complete all outstanding RMA │
│ │ operations at all targets │
├─────────────────────────────────┼──────────────────────────────────┤
│Flush_local(rank) │ Complete locally all outstanding │
│ │ RMA operations at the given │
│ │ target │
├─────────────────────────────────┼──────────────────────────────────┤
│Flush_local_all() │ Complete locally all outstanding │
│ │ RMA opera- tions at all targets │
├─────────────────────────────────┼──────────────────────────────────┤
│Free() │ Free a window │
├─────────────────────────────────┼──────────────────────────────────┤
│Free_keyval(keyval) │ Free an attribute key for │
│ │ windows │
├─────────────────────────────────┼──────────────────────────────────┤
│Get(origin, target_rank[, │ Get data from a memory window on │
│target]) │ a remote process. │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_accumulate(origin, result, │ Fetch-and-accumulate data into │
│target_rank) │ the target process │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_attr(keyval) │ Retrieve attribute value by key │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_errhandler() │ Get the error handler for a │
│ │ window │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_group() │ Return a duplicate of the group │
│ │ of the communicator used to │
│ │ create the window │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_info() │ Return the hints for a windows │
│ │ that are currently in use │
├─────────────────────────────────┼──────────────────────────────────┤
│Get_name() │ Get the print name associated │
│ │ with the window │
├─────────────────────────────────┼──────────────────────────────────┤
│Lock(rank[, lock_type, │ Begin an RMA access epoch at the │
│assertion]) │ target process │
├─────────────────────────────────┼──────────────────────────────────┤
│Lock_all([assertion]) │ Begin an RMA access epoch at all │
│ │ processes │
├─────────────────────────────────┼──────────────────────────────────┤
│Post(group[, assertion]) │ Start an RMA exposure epoch │
├─────────────────────────────────┼──────────────────────────────────┤
│Put(origin, target_rank[, │ Put data into a memory window on │
│target]) │ a remote process. │
├─────────────────────────────────┼──────────────────────────────────┤
│Raccumulate(origin, │ Fetch-and-accumulate data into │
│target_rank[, target, op]) │ the target process │
├─────────────────────────────────┼──────────────────────────────────┤
│Rget(origin, target_rank[, │ Get data from a memory window on │
│target]) │ a remote process. │
├─────────────────────────────────┼──────────────────────────────────┤
│Rget_accumulate(origin, result, │ Accumulate data into the target │
│target_rank) │ process using remote memory │
│ │ access. │
├─────────────────────────────────┼──────────────────────────────────┤
│Rput(origin, target_rank[, │ Put data into a memory window on │
│target]) │ a remote process. │
├─────────────────────────────────┼──────────────────────────────────┤
│Set_attr(keyval, attrval) │ Store attribute value associated │
│ │ with a key │
├─────────────────────────────────┼──────────────────────────────────┤
│Set_errhandler(errhandler) │ Set the error handler for a │
│ │ window │
├─────────────────────────────────┼──────────────────────────────────┤
│Set_info(info) │ Set new values for the hints │
│ │ associated with a window │
├─────────────────────────────────┼──────────────────────────────────┤
│Set_name(name) │ Set the print name associated │
│ │ with the window │
├─────────────────────────────────┼──────────────────────────────────┤
│Shared_query(rank) │ Query the process-local address │
│ │ for remote memory segments │
│ │ created with │
│ │ Win.Allocate_shared() │
├─────────────────────────────────┼──────────────────────────────────┤
│Start(group[, assertion]) │ Start an RMA access epoch for │
│ │ MPI │
├─────────────────────────────────┼──────────────────────────────────┤
│Sync() │ Synchronize public and private │
│ │ copies of the given window │
├─────────────────────────────────┼──────────────────────────────────┤
│Test() │ Test whether an RMA exposure │
│ │ epoch has completed │
├─────────────────────────────────┼──────────────────────────────────┤
│Unlock(rank) │ Complete an RMA access epoch at │
│ │ the target process │
├─────────────────────────────────┼──────────────────────────────────┤
│Unlock_all() │ Complete an RMA access epoch at │
│ │ all processes │
├─────────────────────────────────┼──────────────────────────────────┤
│Wait() │ Complete an RMA exposure epoch │
│ │ begun with Win.Post() │
├─────────────────────────────────┼──────────────────────────────────┤
│f2py(arg) │ │
├─────────────────────────────────┼──────────────────────────────────┤
│py2f() │ │
├─────────────────────────────────┼──────────────────────────────────┤
│tomemory() │ Return window memory buffer │
└─────────────────────────────────┴──────────────────────────────────┘
Attributes Summary
┌───────┬──────────────────────┐
│attrs │ window attributes │
├───────┼──────────────────────┤
│flavor │ window create flavor │
├───────┼──────────────────────┤
│group │ window group │
├───────┼──────────────────────┤
│info │ window info │
├───────┼──────────────────────┤
│model │ window memory model │
├───────┼──────────────────────┤
│name │ window name │
└───────┴──────────────────────┘
Methods Documentation
Accumulate(origin, target_rank, target=None, op=SUM)
Accumulate data into the target process
Parameters
• origin (BufSpec)
• target_rank (int)
• target (Optional[TargetSpec])
• op (Op)
Return type
None
classmethod Allocate(size, disp_unit=1, info=INFO_NULL, comm=COMM_SELF)
Create an window object for one-sided communication
Parameters
• size (int)
• disp_unit (int)
• info (Info)
• comm (Intracomm)
Return type
Win
classmethod Allocate_shared(size, disp_unit=1, info=INFO_NULL, comm=COMM_SELF)
Create an window object for one-sided communication
Parameters
• size (int)
• disp_unit (int)
• info (Info)
• comm (Intracomm)
Return type
Win
Attach(memory)
Attach a local memory region
Parameters
memory (Buffer)
Return type
None
Call_errhandler(errorcode)
Call the error handler installed on a window
Parameters
errorcode (int)
Return type
None
Compare_and_swap(origin, compare, result, target_rank, target_disp=0)
Perform one-sided atomic compare-and-swap
Parameters
• origin (BufSpec)
• compare (BufSpec)
• result (BufSpec)
• target_rank (int)
• target_disp (int)
Return type
None
Complete()
Completes an RMA operations begun after an Win.Start()
Return type
None
classmethod Create(memory, disp_unit=1, info=INFO_NULL, comm=COMM_SELF)
Create an window object for one-sided communication
Parameters
• memory (Union[Buffer, Bottom, None])
• disp_unit (int)
• info (Info)
• comm (Intracomm)
Return type
Win
classmethod Create_dynamic(info=INFO_NULL, comm=COMM_SELF)
Create an window object for one-sided communication
Parameters
• info (Info)
• comm (Intracomm)
Return type
Win
classmethod Create_keyval(copy_fn=None, delete_fn=None, nopython=False)
Create a new attribute key for windows
Parameters
• copy_fn (Optional[Callable[[Win, int, Any], Any]])
• delete_fn (Optional[Callable[[Win, int, Any], None]])
• nopython (bool)
Return type
int
Delete_attr(keyval)
Delete attribute value associated with a key
Parameters
keyval (int)
Return type
None
Detach(memory)
Detach a local memory region
Parameters
memory (Buffer)
Return type
None
Fence(assertion=0)
Perform an MPI fence synchronization on a window
Parameters
assertion (int)
Return type
None
Fetch_and_op(origin, result, target_rank, target_disp=0, op=SUM)
Perform one-sided read-modify-write
Parameters
• origin (BufSpec)
• result (BufSpec)
• target_rank (int)
• target_disp (int)
• op (Op)
Return type
None
Flush(rank)
Complete all outstanding RMA operations at the given target
Parameters
rank (int)
Return type
None
Flush_all()
Complete all outstanding RMA operations at all targets
Return type
None
Flush_local(rank)
Complete locally all outstanding RMA operations at the given target
Parameters
rank (int)
Return type
None
Flush_local_all()
Complete locally all outstanding RMA opera- tions at all targets
Return type
None
Free() Free a window
Return type
None
classmethod Free_keyval(keyval)
Free an attribute key for windows
Parameters
keyval (int)
Return type
int
Get(origin, target_rank, target=None)
Get data from a memory window on a remote process.
Parameters
• origin (BufSpec)
• target_rank (int)
• target (Optional[TargetSpec])
Return type
None
Get_accumulate(origin, result, target_rank, target=None, op=SUM)
Fetch-and-accumulate data into the target process
Parameters
• origin (BufSpec)
• result (BufSpec)
• target_rank (int)
• target (Optional[TargetSpec])
• op (Op)
Return type
None
Get_attr(keyval)
Retrieve attribute value by key
Parameters
keyval (int)
Return type
Optional[Union[int, Any]]
Get_errhandler()
Get the error handler for a window
Return type
Errhandler
Get_group()
Return a duplicate of the group of the communicator used to create the
window
Return type
Group
Get_info()
Return the hints for a windows that are currently in use
Return type
Info
Get_name()
Get the print name associated with the window
Return type
str
Lock(rank, lock_type=LOCK_EXCLUSIVE, assertion=0)
Begin an RMA access epoch at the target process
Parameters
• rank (int)
• lock_type (int)
• assertion (int)
Return type
None
Lock_all(assertion=0)
Begin an RMA access epoch at all processes
Parameters
assertion (int)
Return type
None
Post(group, assertion=0)
Start an RMA exposure epoch
Parameters
• group (Group)
• assertion (int)
Return type
None
Put(origin, target_rank, target=None)
Put data into a memory window on a remote process.
Parameters
• origin (BufSpec)
• target_rank (int)
• target (Optional[TargetSpec])
Return type
None
Raccumulate(origin, target_rank, target=None, op=SUM)
Fetch-and-accumulate data into the target process
Parameters
• origin (BufSpec)
• target_rank (int)
• target (Optional[TargetSpec])
• op (Op)
Return type
Request
Rget(origin, target_rank, target=None)
Get data from a memory window on a remote process.
Parameters
• origin (BufSpec)
• target_rank (int)
• target (Optional[TargetSpec])
Return type
Request
Rget_accumulate(origin, result, target_rank, target=None, op=SUM)
Accumulate data into the target process using remote memory access.
Parameters
• origin (BufSpec)
• result (BufSpec)
• target_rank (int)
• target (Optional[TargetSpec])
• op (Op)
Return type
Request
Rput(origin, target_rank, target=None)
Put data into a memory window on a remote process.
Parameters
• origin (BufSpec)
• target_rank (int)
• target (Optional[TargetSpec])
Return type
Request
Set_attr(keyval, attrval)
Store attribute value associated with a key
Parameters
• keyval (int)
• attrval (Any)
Return type
None
Set_errhandler(errhandler)
Set the error handler for a window
Parameters
errhandler (Errhandler)
Return type
None
Set_info(info)
Set new values for the hints associated with a window
Parameters
info (Info)
Return type
None
Set_name(name)
Set the print name associated with the window
Parameters
name (str)
Return type
None
Shared_query(rank)
Query the process-local address for remote memory segments created with
Win.Allocate_shared()
Parameters
rank (int)
Return type
Tuple[memory, int]
Start(group, assertion=0)
Start an RMA access epoch for MPI
Parameters
• group (Group)
• assertion (int)
Return type
None
Sync() Synchronize public and private copies of the given window
Return type
None
Test() Test whether an RMA exposure epoch has completed
Return type
bool
Unlock(rank)
Complete an RMA access epoch at the target process
Parameters
rank (int)
Return type
None
Unlock_all()
Complete an RMA access epoch at all processes
Return type
None
Wait() Complete an RMA exposure epoch begun with Win.Post()
Return type
Literal[True]
classmethod f2py(arg)
Parameters
arg (int)
Return type
Win
py2f()
Return type
int
tomemory()
Return window memory buffer
Return type
memory
Attributes Documentation
attrs window attributes
flavor window create flavor
group window group
info window info
model window memory model
name window name
mpi4py.MPI.memory
class mpi4py.MPI.memory(buf)
Bases: object
Memory buffer
Parameters
buf (Buffer)
Return type
memory
static __new__(cls, buf)
Parameters
buf (Buffer)
Return type
memory
Methods Summary
┌─────────────────────────────────┬──────────────────────────────────┐
│allocate(nbytes[, clear]) │ Memory allocation │
├─────────────────────────────────┼──────────────────────────────────┤
│fromaddress(address, nbytes[, │ Memory from address and size in │
│readonly]) │ bytes │
├─────────────────────────────────┼──────────────────────────────────┤
│frombuffer(obj[, readonly]) │ Memory from buffer-like object │
├─────────────────────────────────┼──────────────────────────────────┤
│release() │ Release the underlying buffer │
│ │ exposed by the memory object │
├─────────────────────────────────┼──────────────────────────────────┤
│tobytes([order]) │ Return the data in the buffer as │
│ │ a byte string │
├─────────────────────────────────┼──────────────────────────────────┤
│toreadonly() │ Return a readonly version of the │
│ │ memory object │
└─────────────────────────────────┴──────────────────────────────────┘
Attributes Summary
┌─────────┬──────────────────────────────────┐
│address │ Memory address │
├─────────┼──────────────────────────────────┤
│format │ A string with the format of each │
│ │ element │
├─────────┼──────────────────────────────────┤
│itemsize │ The size in bytes of each │
│ │ element │
├─────────┼──────────────────────────────────┤
│nbytes │ Memory size (in bytes) │
├─────────┼──────────────────────────────────┤
│obj │ The underlying object of the │
│ │ memory │
├─────────┼──────────────────────────────────┤
│readonly │ Boolean indicating whether the │
│ │ memory is read-only │
└─────────┴──────────────────────────────────┘
Methods Documentation
static allocate(nbytes, clear=False)
Memory allocation
Parameters
• nbytes (int)
• clear (bool)
Return type
memory
static fromaddress(address, nbytes, readonly=False)
Memory from address and size in bytes
Parameters
• address (int)
• nbytes (int)
• readonly (bool)
Return type
memory
static frombuffer(obj, readonly=False)
Memory from buffer-like object
Parameters
• obj (Buffer)
• readonly (bool)
Return type
memory
release()
Release the underlying buffer exposed by the memory object
Return type
None
tobytes(order=None)
Return the data in the buffer as a byte string
Parameters
order (Optional[str])
Return type
bytes
toreadonly()
Return a readonly version of the memory object
Return type
memory
Attributes Documentation
address
Memory address
format A string with the format of each element
itemsize
The size in bytes of each element
nbytes Memory size (in bytes)
obj The underlying object of the memory
readonly
Boolean indicating whether the memory is read-only
Exceptions
┌──────────────────┬─────────────────┐
│Exception([ierr]) │ Exception class │
└──────────────────┴─────────────────┘
mpi4py.MPI.Exception
exception mpi4py.MPI.Exception(ierr=SUCCESS)
Bases: RuntimeError
Exception class
Parameters
ierr (int)
Return type
Exception
static __new__(cls, ierr=SUCCESS)
Parameters
ierr (int)
Return type
Exception
Methods Summary
┌───────────────────┬──────────────┐
│Get_error_class() │ Error class │
├───────────────────┼──────────────┤
│Get_error_code() │ Error code │
├───────────────────┼──────────────┤
│Get_error_string() │ Error string │
└───────────────────┴──────────────┘
Attributes Summary
┌─────────────┬──────────────┐
│error_class │ error class │
├─────────────┼──────────────┤
│error_code │ error code │
├─────────────┼──────────────┤
│error_string │ error string │
└─────────────┴──────────────┘
Methods Documentation
Get_error_class()
Error class
Return type
int
Get_error_code()
Error code
Return type
int
Get_error_string()
Error string
Return type
str
Attributes Documentation
error_class
error class
error_code
error code
error_string
error string
Functions
┌─────────────────────────────┬──────────────────────────────────┐
│Add_error_class() │ Add an error class to the known │
│ │ error classes │
├─────────────────────────────┼──────────────────────────────────┤
│Add_error_code(errorclass) │ Add an error code to an error │
│ │ class │
├─────────────────────────────┼──────────────────────────────────┤
│Add_error_string(errorcode, │ Associate an error string with │
│string) │ an error class or errorcode │
├─────────────────────────────┼──────────────────────────────────┤
│Aint_add(base, disp) │ Return the sum of base address │
│ │ and displacement │
├─────────────────────────────┼──────────────────────────────────┤
│Aint_diff(addr1, addr2) │ Return the difference between │
│ │ absolute addresses │
├─────────────────────────────┼──────────────────────────────────┤
│Alloc_mem(size[, info]) │ Allocate memory for message │
│ │ passing and RMA │
├─────────────────────────────┼──────────────────────────────────┤
│Attach_buffer(buf) │ Attach a user-provided buffer │
│ │ for sending in buffered mode │
├─────────────────────────────┼──────────────────────────────────┤
│Close_port(port_name) │ Close a port │
├─────────────────────────────┼──────────────────────────────────┤
│Compute_dims(nnodes, dims) │ Return a balanced distribution │
│ │ of processes per coordinate │
│ │ direction │
├─────────────────────────────┼──────────────────────────────────┤
│Detach_buffer() │ Remove an existing attached │
│ │ buffer │
├─────────────────────────────┼──────────────────────────────────┤
│Finalize() │ Terminate the MPI execution │
│ │ environment │
├─────────────────────────────┼──────────────────────────────────┤
│Free_mem(mem) │ Free memory allocated with │
│ │ Alloc_mem() │
├─────────────────────────────┼──────────────────────────────────┤
│Get_address(location) │ Get the address of a location in │
│ │ memory │
├─────────────────────────────┼──────────────────────────────────┤
│Get_error_class(errorcode) │ Convert an error code into an │
│ │ error class │
├─────────────────────────────┼──────────────────────────────────┤
│Get_error_string(errorcode) │ Return the error string for a │
│ │ given error class or error code │
├─────────────────────────────┼──────────────────────────────────┤
│Get_library_version() │ Obtain the version string of the │
│ │ MPI library │
├─────────────────────────────┼──────────────────────────────────┤
│Get_processor_name() │ Obtain the name of the calling │
│ │ processor │
├─────────────────────────────┼──────────────────────────────────┤
│Get_version() │ Obtain the version number of the │
│ │ MPI standard supported by the │
│ │ implementation as a tuple │
│ │ (version, subversion) │
├─────────────────────────────┼──────────────────────────────────┤
│Init() │ Initialize the MPI execution │
│ │ environment │
├─────────────────────────────┼──────────────────────────────────┤
│Init_thread([required]) │ Initialize the MPI execution │
│ │ environment │
├─────────────────────────────┼──────────────────────────────────┤
│Is_finalized() │ Indicates whether Finalize has │
│ │ completed │
├─────────────────────────────┼──────────────────────────────────┤
│Is_initialized() │ Indicates whether Init has been │
│ │ called │
├─────────────────────────────┼──────────────────────────────────┤
│Is_thread_main() │ Indicate whether this thread │
│ │ called Init or Init_thread │
├─────────────────────────────┼──────────────────────────────────┤
│Lookup_name(service_name[, │ Lookup a port name given a │
│info]) │ service name │
├─────────────────────────────┼──────────────────────────────────┤
│Open_port([info]) │ Return an address that can be │
│ │ used to establish connections │
│ │ between groups of MPI processes │
├─────────────────────────────┼──────────────────────────────────┤
│Pcontrol(level) │ Control profiling │
├─────────────────────────────┼──────────────────────────────────┤
│Publish_name(service_name, │ Publish a service name │
│port_name[, info]) │ │
├─────────────────────────────┼──────────────────────────────────┤
│Query_thread() │ Return the level of thread │
│ │ support provided by the MPI │
│ │ library │
├─────────────────────────────┼──────────────────────────────────┤
│Register_datarep(datarep, │ Register user-defined data │
│read_fn, write_fn, ...) │ representations │
├─────────────────────────────┼──────────────────────────────────┤
│Unpublish_name(service_name, │ Unpublish a service name │
│port_name[, info]) │ │
├─────────────────────────────┼──────────────────────────────────┤
│Wtick() │ Return the resolution of Wtime │
├─────────────────────────────┼──────────────────────────────────┤
│Wtime() │ Return an elapsed time on the │
│ │ calling processor │
├─────────────────────────────┼──────────────────────────────────┤
│get_vendor() │ Infomation about the underlying │
│ │ MPI implementation │
└─────────────────────────────┴──────────────────────────────────┘
mpi4py.MPI.Add_error_class
mpi4py.MPI.Add_error_class()
Add an error class to the known error classes
Return type
int
mpi4py.MPI.Add_error_code
mpi4py.MPI.Add_error_code(errorclass)
Add an error code to an error class
Parameters
errorclass (int)
Return type
int
mpi4py.MPI.Add_error_string
mpi4py.MPI.Add_error_string(errorcode, string)
Associate an error string with an error class or errorcode
Parameters
• errorcode (int)
• string (str)
Return type
None
mpi4py.MPI.Aint_add
mpi4py.MPI.Aint_add(base, disp)
Return the sum of base address and displacement
Parameters
• base (int)
• disp (int)
Return type
int
mpi4py.MPI.Aint_diff
mpi4py.MPI.Aint_diff(addr1, addr2)
Return the difference between absolute addresses
Parameters
• addr1 (int)
• addr2 (int)
Return type
int
mpi4py.MPI.Alloc_mem
mpi4py.MPI.Alloc_mem(size, info=INFO_NULL)
Allocate memory for message passing and RMA
Parameters
• size (int)
• info (Info)
Return type
memory
mpi4py.MPI.Attach_buffer
mpi4py.MPI.Attach_buffer(buf)
Attach a user-provided buffer for sending in buffered mode
Parameters
buf (Buffer)
Return type
None
mpi4py.MPI.Close_port
mpi4py.MPI.Close_port(port_name)
Close a port
Parameters
port_name (str)
Return type
None
mpi4py.MPI.Compute_dims
mpi4py.MPI.Compute_dims(nnodes, dims)
Return a balanced distribution of processes per coordinate direction
Parameters
• nnodes (int)
• dims (Union[int, Sequence[int]])
Return type
List[int]
mpi4py.MPI.Detach_buffer
mpi4py.MPI.Detach_buffer()
Remove an existing attached buffer
Return type
Buffer
mpi4py.MPI.Finalize
mpi4py.MPI.Finalize()
Terminate the MPI execution environment
Return type
None
mpi4py.MPI.Free_mem
mpi4py.MPI.Free_mem(mem)
Free memory allocated with Alloc_mem()
Parameters
mem (memory)
Return type
None
mpi4py.MPI.Get_address
mpi4py.MPI.Get_address(location)
Get the address of a location in memory
Parameters
location (Union[Buffer, Bottom])
Return type
int
mpi4py.MPI.Get_error_class
mpi4py.MPI.Get_error_class(errorcode)
Convert an error code into an error class
Parameters
errorcode (int)
Return type
int
mpi4py.MPI.Get_error_string
mpi4py.MPI.Get_error_string(errorcode)
Return the error string for a given error class or error code
Parameters
errorcode (int)
Return type
str
mpi4py.MPI.Get_library_version
mpi4py.MPI.Get_library_version()
Obtain the version string of the MPI library
Return type
str
mpi4py.MPI.Get_processor_name
mpi4py.MPI.Get_processor_name()
Obtain the name of the calling processor
Return type
str
mpi4py.MPI.Get_version
mpi4py.MPI.Get_version()
Obtain the version number of the MPI standard supported by the implementation as a
tuple (version, subversion)
Return type
Tuple[int, int]
mpi4py.MPI.Init
mpi4py.MPI.Init()
Initialize the MPI execution environment
Return type
None
mpi4py.MPI.Init_thread
mpi4py.MPI.Init_thread(required=THREAD_MULTIPLE)
Initialize the MPI execution environment
Parameters
required (int)
Return type
int
mpi4py.MPI.Is_finalized
mpi4py.MPI.Is_finalized()
Indicates whether Finalize has completed
Return type
bool
mpi4py.MPI.Is_initialized
mpi4py.MPI.Is_initialized()
Indicates whether Init has been called
Return type
bool
mpi4py.MPI.Is_thread_main
mpi4py.MPI.Is_thread_main()
Indicate whether this thread called Init or Init_thread
Return type
bool
mpi4py.MPI.Lookup_name
mpi4py.MPI.Lookup_name(service_name, info=INFO_NULL)
Lookup a port name given a service name
Parameters
• service_name (str)
• info (Info)
Return type
str
mpi4py.MPI.Open_port
mpi4py.MPI.Open_port(info=INFO_NULL)
Return an address that can be used to establish connections between groups of MPI
processes
Parameters
info (Info)
Return type
str
mpi4py.MPI.Pcontrol
mpi4py.MPI.Pcontrol(level)
Control profiling
Parameters
level (int)
Return type
None
mpi4py.MPI.Publish_name
mpi4py.MPI.Publish_name(service_name, port_name, info=INFO_NULL)
Publish a service name
Parameters
• service_name (str)
• port_name (str)
• info (Info)
Return type
None
mpi4py.MPI.Query_thread
mpi4py.MPI.Query_thread()
Return the level of thread support provided by the MPI library
Return type
int
mpi4py.MPI.Register_datarep
mpi4py.MPI.Register_datarep(datarep, read_fn, write_fn, extent_fn)
Register user-defined data representations
Parameters
• datarep (str)
• read_fn (Callable[[Buffer, Datatype, int, Buffer, int], None])
• write_fn (Callable[[Buffer, Datatype, int, Buffer, int], None])
• extent_fn (Callable[[Datatype], int])
Return type
None
mpi4py.MPI.Unpublish_name
mpi4py.MPI.Unpublish_name(service_name, port_name, info=INFO_NULL)
Unpublish a service name
Parameters
• service_name (str)
• port_name (str)
• info (Info)
Return type
None
mpi4py.MPI.Wtick
mpi4py.MPI.Wtick()
Return the resolution of Wtime
Return type
float
mpi4py.MPI.Wtime
mpi4py.MPI.Wtime()
Return an elapsed time on the calling processor
Return type
float
mpi4py.MPI.get_vendor
mpi4py.MPI.get_vendor()
Infomation about the underlying MPI implementation
Returns
• a string with the name of the MPI implementation
• an integer 3-tuple version (major, minor, micro)
Return type
Tuple[str, Tuple[int, int, int]]
Attributes
┌───────────────────────────┬──────────────────────────────────┐
│UNDEFINED │ int UNDEFINED │
├───────────────────────────┼──────────────────────────────────┤
│ANY_SOURCE │ int ANY_SOURCE │
├───────────────────────────┼──────────────────────────────────┤
│ANY_TAG │ int ANY_TAG │
├───────────────────────────┼──────────────────────────────────┤
│PROC_NULL │ int PROC_NULL │
├───────────────────────────┼──────────────────────────────────┤
│ROOT │ int ROOT │
├───────────────────────────┼──────────────────────────────────┤
│BOTTOM │ Bottom BOTTOM │
├───────────────────────────┼──────────────────────────────────┤
│IN_PLACE │ InPlace IN_PLACE │
├───────────────────────────┼──────────────────────────────────┤
│KEYVAL_INVALID │ int KEYVAL_INVALID │
├───────────────────────────┼──────────────────────────────────┤
│TAG_UB │ int TAG_UB │
├───────────────────────────┼──────────────────────────────────┤
│HOST │ int HOST │
├───────────────────────────┼──────────────────────────────────┤
│IO │ int IO │
├───────────────────────────┼──────────────────────────────────┤
│WTIME_IS_GLOBAL │ int WTIME_IS_GLOBAL │
├───────────────────────────┼──────────────────────────────────┤
│UNIVERSE_SIZE │ int UNIVERSE_SIZE │
├───────────────────────────┼──────────────────────────────────┤
│APPNUM │ int APPNUM │
├───────────────────────────┼──────────────────────────────────┤
│LASTUSEDCODE │ int LASTUSEDCODE │
├───────────────────────────┼──────────────────────────────────┤
│WIN_BASE │ int WIN_BASE │
├───────────────────────────┼──────────────────────────────────┤
│WIN_SIZE │ int WIN_SIZE │
├───────────────────────────┼──────────────────────────────────┤
│WIN_DISP_UNIT │ int WIN_DISP_UNIT │
├───────────────────────────┼──────────────────────────────────┤
│WIN_CREATE_FLAVOR │ int WIN_CREATE_FLAVOR │
├───────────────────────────┼──────────────────────────────────┤
│WIN_FLAVOR │ int WIN_FLAVOR │
├───────────────────────────┼──────────────────────────────────┤
│WIN_MODEL │ int WIN_MODEL │
├───────────────────────────┼──────────────────────────────────┤
│SUCCESS │ int SUCCESS │
├───────────────────────────┼──────────────────────────────────┤
│ERR_LASTCODE │ int ERR_LASTCODE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_COMM │ int ERR_COMM │
├───────────────────────────┼──────────────────────────────────┤
│ERR_GROUP │ int ERR_GROUP │
├───────────────────────────┼──────────────────────────────────┤
│ERR_TYPE │ int ERR_TYPE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_REQUEST │ int ERR_REQUEST │
├───────────────────────────┼──────────────────────────────────┤
│ERR_OP │ int ERR_OP │
├───────────────────────────┼──────────────────────────────────┤
│ERR_BUFFER │ int ERR_BUFFER │
├───────────────────────────┼──────────────────────────────────┤
│ERR_COUNT │ int ERR_COUNT │
├───────────────────────────┼──────────────────────────────────┤
│ERR_TAG │ int ERR_TAG │
├───────────────────────────┼──────────────────────────────────┤
│ERR_RANK │ int ERR_RANK │
├───────────────────────────┼──────────────────────────────────┤
│ERR_ROOT │ int ERR_ROOT │
├───────────────────────────┼──────────────────────────────────┤
│ERR_TRUNCATE │ int ERR_TRUNCATE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_IN_STATUS │ int ERR_IN_STATUS │
├───────────────────────────┼──────────────────────────────────┤
│ERR_PENDING │ int ERR_PENDING │
├───────────────────────────┼──────────────────────────────────┤
│ERR_TOPOLOGY │ int ERR_TOPOLOGY │
├───────────────────────────┼──────────────────────────────────┤
│ERR_DIMS │ int ERR_DIMS │
├───────────────────────────┼──────────────────────────────────┤
│ERR_ARG │ int ERR_ARG │
├───────────────────────────┼──────────────────────────────────┤
│ERR_OTHER │ int ERR_OTHER │
├───────────────────────────┼──────────────────────────────────┤
│ERR_UNKNOWN │ int ERR_UNKNOWN │
├───────────────────────────┼──────────────────────────────────┤
│ERR_INTERN │ int ERR_INTERN │
├───────────────────────────┼──────────────────────────────────┤
│ERR_INFO │ int ERR_INFO │
├───────────────────────────┼──────────────────────────────────┤
│ERR_FILE │ int ERR_FILE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_WIN │ int ERR_WIN │
├───────────────────────────┼──────────────────────────────────┤
│ERR_KEYVAL │ int ERR_KEYVAL │
├───────────────────────────┼──────────────────────────────────┤
│ERR_INFO_KEY │ int ERR_INFO_KEY │
├───────────────────────────┼──────────────────────────────────┤
│ERR_INFO_VALUE │ int ERR_INFO_VALUE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_INFO_NOKEY │ int ERR_INFO_NOKEY │
├───────────────────────────┼──────────────────────────────────┤
│ERR_ACCESS │ int ERR_ACCESS │
├───────────────────────────┼──────────────────────────────────┤
│ERR_AMODE │ int ERR_AMODE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_BAD_FILE │ int ERR_BAD_FILE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_FILE_EXISTS │ int ERR_FILE_EXISTS │
├───────────────────────────┼──────────────────────────────────┤
│ERR_FILE_IN_USE │ int ERR_FILE_IN_USE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_NO_SPACE │ int ERR_NO_SPACE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_NO_SUCH_FILE │ int ERR_NO_SUCH_FILE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_IO │ int ERR_IO │
├───────────────────────────┼──────────────────────────────────┤
│ERR_READ_ONLY │ int ERR_READ_ONLY │
├───────────────────────────┼──────────────────────────────────┤
│ERR_CONVERSION │ int ERR_CONVERSION │
├───────────────────────────┼──────────────────────────────────┤
│ERR_DUP_DATAREP │ int ERR_DUP_DATAREP │
├───────────────────────────┼──────────────────────────────────┤
│ERR_UNSUPPORTED_DATAREP │ int ERR_UNSUPPORTED_DATAREP │
├───────────────────────────┼──────────────────────────────────┤
│ERR_UNSUPPORTED_OPERATION │ int ERR_UNSUPPORTED_OPERATION │
├───────────────────────────┼──────────────────────────────────┤
│ERR_NAME │ int ERR_NAME │
├───────────────────────────┼──────────────────────────────────┤
│ERR_NO_MEM │ int ERR_NO_MEM │
├───────────────────────────┼──────────────────────────────────┤
│ERR_NOT_SAME │ int ERR_NOT_SAME │
├───────────────────────────┼──────────────────────────────────┤
│ERR_PORT │ int ERR_PORT │
├───────────────────────────┼──────────────────────────────────┤
│ERR_QUOTA │ int ERR_QUOTA │
├───────────────────────────┼──────────────────────────────────┤
│ERR_SERVICE │ int ERR_SERVICE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_SPAWN │ int ERR_SPAWN │
├───────────────────────────┼──────────────────────────────────┤
│ERR_BASE │ int ERR_BASE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_SIZE │ int ERR_SIZE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_DISP │ int ERR_DISP │
├───────────────────────────┼──────────────────────────────────┤
│ERR_ASSERT │ int ERR_ASSERT │
├───────────────────────────┼──────────────────────────────────┤
│ERR_LOCKTYPE │ int ERR_LOCKTYPE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_RMA_CONFLICT │ int ERR_RMA_CONFLICT │
├───────────────────────────┼──────────────────────────────────┤
│ERR_RMA_SYNC │ int ERR_RMA_SYNC │
├───────────────────────────┼──────────────────────────────────┤
│ERR_RMA_RANGE │ int ERR_RMA_RANGE │
├───────────────────────────┼──────────────────────────────────┤
│ERR_RMA_ATTACH │ int ERR_RMA_ATTACH │
├───────────────────────────┼──────────────────────────────────┤
│ERR_RMA_SHARED │ int ERR_RMA_SHARED │
├───────────────────────────┼──────────────────────────────────┤
│ERR_RMA_FLAVOR │ int ERR_RMA_FLAVOR │
├───────────────────────────┼──────────────────────────────────┤
│ORDER_C │ int ORDER_C │
├───────────────────────────┼──────────────────────────────────┤
│ORDER_FORTRAN │ int ORDER_FORTRAN │
├───────────────────────────┼──────────────────────────────────┤
│ORDER_F │ int ORDER_F │
├───────────────────────────┼──────────────────────────────────┤
│TYPECLASS_INTEGER │ int TYPECLASS_INTEGER │
├───────────────────────────┼──────────────────────────────────┤
│TYPECLASS_REAL │ int TYPECLASS_REAL │
├───────────────────────────┼──────────────────────────────────┤
│TYPECLASS_COMPLEX │ int TYPECLASS_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│DISTRIBUTE_NONE │ int DISTRIBUTE_NONE │
├───────────────────────────┼──────────────────────────────────┤
│DISTRIBUTE_BLOCK │ int DISTRIBUTE_BLOCK │
├───────────────────────────┼──────────────────────────────────┤
│DISTRIBUTE_CYCLIC │ int DISTRIBUTE_CYCLIC │
├───────────────────────────┼──────────────────────────────────┤
│DISTRIBUTE_DFLT_DARG │ int DISTRIBUTE_DFLT_DARG │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_NAMED │ int COMBINER_NAMED │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_DUP │ int COMBINER_DUP │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_CONTIGUOUS │ int COMBINER_CONTIGUOUS │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_VECTOR │ int COMBINER_VECTOR │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_HVECTOR │ int COMBINER_HVECTOR │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_INDEXED │ int COMBINER_INDEXED │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_HINDEXED │ int COMBINER_HINDEXED │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_INDEXED_BLOCK │ int COMBINER_INDEXED_BLOCK │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_HINDEXED_BLOCK │ int COMBINER_HINDEXED_BLOCK │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_STRUCT │ int COMBINER_STRUCT │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_SUBARRAY │ int COMBINER_SUBARRAY │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_DARRAY │ int COMBINER_DARRAY │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_RESIZED │ int COMBINER_RESIZED │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_F90_REAL │ int COMBINER_F90_REAL │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_F90_COMPLEX │ int COMBINER_F90_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│COMBINER_F90_INTEGER │ int COMBINER_F90_INTEGER │
├───────────────────────────┼──────────────────────────────────┤
│IDENT │ int IDENT │
├───────────────────────────┼──────────────────────────────────┤
│CONGRUENT │ int CONGRUENT │
├───────────────────────────┼──────────────────────────────────┤
│SIMILAR │ int SIMILAR │
├───────────────────────────┼──────────────────────────────────┤
│UNEQUAL │ int UNEQUAL │
├───────────────────────────┼──────────────────────────────────┤
│CART │ int CART │
├───────────────────────────┼──────────────────────────────────┤
│GRAPH │ int GRAPH │
├───────────────────────────┼──────────────────────────────────┤
│DIST_GRAPH │ int DIST_GRAPH │
├───────────────────────────┼──────────────────────────────────┤
│UNWEIGHTED │ int UNWEIGHTED │
├───────────────────────────┼──────────────────────────────────┤
│WEIGHTS_EMPTY │ int WEIGHTS_EMPTY │
├───────────────────────────┼──────────────────────────────────┤
│COMM_TYPE_SHARED │ int COMM_TYPE_SHARED │
├───────────────────────────┼──────────────────────────────────┤
│BSEND_OVERHEAD │ int BSEND_OVERHEAD │
├───────────────────────────┼──────────────────────────────────┤
│WIN_FLAVOR_CREATE │ int WIN_FLAVOR_CREATE │
├───────────────────────────┼──────────────────────────────────┤
│WIN_FLAVOR_ALLOCATE │ int WIN_FLAVOR_ALLOCATE │
├───────────────────────────┼──────────────────────────────────┤
│WIN_FLAVOR_DYNAMIC │ int WIN_FLAVOR_DYNAMIC │
├───────────────────────────┼──────────────────────────────────┤
│WIN_FLAVOR_SHARED │ int WIN_FLAVOR_SHARED │
├───────────────────────────┼──────────────────────────────────┤
│WIN_SEPARATE │ int WIN_SEPARATE │
├───────────────────────────┼──────────────────────────────────┤
│WIN_UNIFIED │ int WIN_UNIFIED │
├───────────────────────────┼──────────────────────────────────┤
│MODE_NOCHECK │ int MODE_NOCHECK │
├───────────────────────────┼──────────────────────────────────┤
│MODE_NOSTORE │ int MODE_NOSTORE │
├───────────────────────────┼──────────────────────────────────┤
│MODE_NOPUT │ int MODE_NOPUT │
├───────────────────────────┼──────────────────────────────────┤
│MODE_NOPRECEDE │ int MODE_NOPRECEDE │
├───────────────────────────┼──────────────────────────────────┤
│MODE_NOSUCCEED │ int MODE_NOSUCCEED │
├───────────────────────────┼──────────────────────────────────┤
│LOCK_EXCLUSIVE │ int LOCK_EXCLUSIVE │
├───────────────────────────┼──────────────────────────────────┤
│LOCK_SHARED │ int LOCK_SHARED │
├───────────────────────────┼──────────────────────────────────┤
│MODE_RDONLY │ int MODE_RDONLY │
├───────────────────────────┼──────────────────────────────────┤
│MODE_WRONLY │ int MODE_WRONLY │
├───────────────────────────┼──────────────────────────────────┤
│MODE_RDWR │ int MODE_RDWR │
├───────────────────────────┼──────────────────────────────────┤
│MODE_CREATE │ int MODE_CREATE │
├───────────────────────────┼──────────────────────────────────┤
│MODE_EXCL │ int MODE_EXCL │
├───────────────────────────┼──────────────────────────────────┤
│MODE_DELETE_ON_CLOSE │ int MODE_DELETE_ON_CLOSE │
├───────────────────────────┼──────────────────────────────────┤
│MODE_UNIQUE_OPEN │ int MODE_UNIQUE_OPEN │
├───────────────────────────┼──────────────────────────────────┤
│MODE_SEQUENTIAL │ int MODE_SEQUENTIAL │
├───────────────────────────┼──────────────────────────────────┤
│MODE_APPEND │ int MODE_APPEND │
├───────────────────────────┼──────────────────────────────────┤
│SEEK_SET │ int SEEK_SET │
├───────────────────────────┼──────────────────────────────────┤
│SEEK_CUR │ int SEEK_CUR │
├───────────────────────────┼──────────────────────────────────┤
│SEEK_END │ int SEEK_END │
├───────────────────────────┼──────────────────────────────────┤
│DISPLACEMENT_CURRENT │ int DISPLACEMENT_CURRENT │
├───────────────────────────┼──────────────────────────────────┤
│DISP_CUR │ int DISP_CUR │
├───────────────────────────┼──────────────────────────────────┤
│THREAD_SINGLE │ int THREAD_SINGLE │
├───────────────────────────┼──────────────────────────────────┤
│THREAD_FUNNELED │ int THREAD_FUNNELED │
├───────────────────────────┼──────────────────────────────────┤
│THREAD_SERIALIZED │ int THREAD_SERIALIZED │
├───────────────────────────┼──────────────────────────────────┤
│THREAD_MULTIPLE │ int THREAD_MULTIPLE │
├───────────────────────────┼──────────────────────────────────┤
│VERSION │ int VERSION │
├───────────────────────────┼──────────────────────────────────┤
│SUBVERSION │ int SUBVERSION │
├───────────────────────────┼──────────────────────────────────┤
│MAX_PROCESSOR_NAME │ int MAX_PROCESSOR_NAME │
├───────────────────────────┼──────────────────────────────────┤
│MAX_ERROR_STRING │ int MAX_ERROR_STRING │
├───────────────────────────┼──────────────────────────────────┤
│MAX_PORT_NAME │ int MAX_PORT_NAME │
├───────────────────────────┼──────────────────────────────────┤
│MAX_INFO_KEY │ int MAX_INFO_KEY │
├───────────────────────────┼──────────────────────────────────┤
│MAX_INFO_VAL │ int MAX_INFO_VAL │
├───────────────────────────┼──────────────────────────────────┤
│MAX_OBJECT_NAME │ int MAX_OBJECT_NAME │
├───────────────────────────┼──────────────────────────────────┤
│MAX_DATAREP_STRING │ int MAX_DATAREP_STRING │
├───────────────────────────┼──────────────────────────────────┤
│MAX_LIBRARY_VERSION_STRING │ int MAX_LIBRARY_VERSION_STRING │
├───────────────────────────┼──────────────────────────────────┤
│DATATYPE_NULL │ Datatype DATATYPE_NULL │
├───────────────────────────┼──────────────────────────────────┤
│UB │ Datatype UB │
├───────────────────────────┼──────────────────────────────────┤
│LB │ Datatype LB │
├───────────────────────────┼──────────────────────────────────┤
│PACKED │ Datatype PACKED │
├───────────────────────────┼──────────────────────────────────┤
│BYTE │ Datatype BYTE │
├───────────────────────────┼──────────────────────────────────┤
│AINT │ Datatype AINT │
├───────────────────────────┼──────────────────────────────────┤
│OFFSET │ Datatype OFFSET │
├───────────────────────────┼──────────────────────────────────┤
│COUNT │ Datatype COUNT │
├───────────────────────────┼──────────────────────────────────┤
│CHAR │ Datatype CHAR │
├───────────────────────────┼──────────────────────────────────┤
│WCHAR │ Datatype WCHAR │
├───────────────────────────┼──────────────────────────────────┤
│SIGNED_CHAR │ Datatype SIGNED_CHAR │
├───────────────────────────┼──────────────────────────────────┤
│SHORT │ Datatype SHORT │
├───────────────────────────┼──────────────────────────────────┤
│INT │ Datatype INT │
├───────────────────────────┼──────────────────────────────────┤
│LONG │ Datatype LONG │
├───────────────────────────┼──────────────────────────────────┤
│LONG_LONG │ Datatype LONG_LONG │
├───────────────────────────┼──────────────────────────────────┤
│UNSIGNED_CHAR │ Datatype UNSIGNED_CHAR │
├───────────────────────────┼──────────────────────────────────┤
│UNSIGNED_SHORT │ Datatype UNSIGNED_SHORT │
├───────────────────────────┼──────────────────────────────────┤
│UNSIGNED │ Datatype UNSIGNED │
├───────────────────────────┼──────────────────────────────────┤
│UNSIGNED_LONG │ Datatype UNSIGNED_LONG │
├───────────────────────────┼──────────────────────────────────┤
│UNSIGNED_LONG_LONG │ Datatype UNSIGNED_LONG_LONG │
├───────────────────────────┼──────────────────────────────────┤
│FLOAT │ Datatype FLOAT │
├───────────────────────────┼──────────────────────────────────┤
│DOUBLE │ Datatype DOUBLE │
├───────────────────────────┼──────────────────────────────────┤
│LONG_DOUBLE │ Datatype LONG_DOUBLE │
├───────────────────────────┼──────────────────────────────────┤
│C_BOOL │ Datatype C_BOOL │
├───────────────────────────┼──────────────────────────────────┤
│INT8_T │ Datatype INT8_T │
├───────────────────────────┼──────────────────────────────────┤
│INT16_T │ Datatype INT16_T │
├───────────────────────────┼──────────────────────────────────┤
│INT32_T │ Datatype INT32_T │
├───────────────────────────┼──────────────────────────────────┤
│INT64_T │ Datatype INT64_T │
├───────────────────────────┼──────────────────────────────────┤
│UINT8_T │ Datatype UINT8_T │
├───────────────────────────┼──────────────────────────────────┤
│UINT16_T │ Datatype UINT16_T │
├───────────────────────────┼──────────────────────────────────┤
│UINT32_T │ Datatype UINT32_T │
├───────────────────────────┼──────────────────────────────────┤
│UINT64_T │ Datatype UINT64_T │
├───────────────────────────┼──────────────────────────────────┤
│C_COMPLEX │ Datatype C_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│C_FLOAT_COMPLEX │ Datatype C_FLOAT_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│C_DOUBLE_COMPLEX │ Datatype C_DOUBLE_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│C_LONG_DOUBLE_COMPLEX │ Datatype C_LONG_DOUBLE_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│CXX_BOOL │ Datatype CXX_BOOL │
├───────────────────────────┼──────────────────────────────────┤
│CXX_FLOAT_COMPLEX │ Datatype CXX_FLOAT_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│CXX_DOUBLE_COMPLEX │ Datatype CXX_DOUBLE_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│CXX_LONG_DOUBLE_COMPLEX │ Datatype CXX_LONG_DOUBLE_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│SHORT_INT │ Datatype SHORT_INT │
├───────────────────────────┼──────────────────────────────────┤
│INT_INT │ Datatype INT_INT │
├───────────────────────────┼──────────────────────────────────┤
│TWOINT │ Datatype TWOINT │
├───────────────────────────┼──────────────────────────────────┤
│LONG_INT │ Datatype LONG_INT │
├───────────────────────────┼──────────────────────────────────┤
│FLOAT_INT │ Datatype FLOAT_INT │
├───────────────────────────┼──────────────────────────────────┤
│DOUBLE_INT │ Datatype DOUBLE_INT │
├───────────────────────────┼──────────────────────────────────┤
│LONG_DOUBLE_INT │ Datatype LONG_DOUBLE_INT │
├───────────────────────────┼──────────────────────────────────┤
│CHARACTER │ Datatype CHARACTER │
├───────────────────────────┼──────────────────────────────────┤
│LOGICAL │ Datatype LOGICAL │
├───────────────────────────┼──────────────────────────────────┤
│INTEGER │ Datatype INTEGER │
├───────────────────────────┼──────────────────────────────────┤
│REAL │ Datatype REAL │
├───────────────────────────┼──────────────────────────────────┤
│DOUBLE_PRECISION │ Datatype DOUBLE_PRECISION │
├───────────────────────────┼──────────────────────────────────┤
│COMPLEX │ Datatype COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│DOUBLE_COMPLEX │ Datatype DOUBLE_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│LOGICAL1 │ Datatype LOGICAL1 │
├───────────────────────────┼──────────────────────────────────┤
│LOGICAL2 │ Datatype LOGICAL2 │
├───────────────────────────┼──────────────────────────────────┤
│LOGICAL4 │ Datatype LOGICAL4 │
├───────────────────────────┼──────────────────────────────────┤
│LOGICAL8 │ Datatype LOGICAL8 │
├───────────────────────────┼──────────────────────────────────┤
│INTEGER1 │ Datatype INTEGER1 │
├───────────────────────────┼──────────────────────────────────┤
│INTEGER2 │ Datatype INTEGER2 │
├───────────────────────────┼──────────────────────────────────┤
│INTEGER4 │ Datatype INTEGER4 │
├───────────────────────────┼──────────────────────────────────┤
│INTEGER8 │ Datatype INTEGER8 │
├───────────────────────────┼──────────────────────────────────┤
│INTEGER16 │ Datatype INTEGER16 │
├───────────────────────────┼──────────────────────────────────┤
│REAL2 │ Datatype REAL2 │
├───────────────────────────┼──────────────────────────────────┤
│REAL4 │ Datatype REAL4 │
├───────────────────────────┼──────────────────────────────────┤
│REAL8 │ Datatype REAL8 │
├───────────────────────────┼──────────────────────────────────┤
│REAL16 │ Datatype REAL16 │
├───────────────────────────┼──────────────────────────────────┤
│COMPLEX4 │ Datatype COMPLEX4 │
├───────────────────────────┼──────────────────────────────────┤
│COMPLEX8 │ Datatype COMPLEX8 │
├───────────────────────────┼──────────────────────────────────┤
│COMPLEX16 │ Datatype COMPLEX16 │
├───────────────────────────┼──────────────────────────────────┤
│COMPLEX32 │ Datatype COMPLEX32 │
├───────────────────────────┼──────────────────────────────────┤
│UNSIGNED_INT │ Datatype UNSIGNED_INT │
├───────────────────────────┼──────────────────────────────────┤
│SIGNED_SHORT │ Datatype SIGNED_SHORT │
├───────────────────────────┼──────────────────────────────────┤
│SIGNED_INT │ Datatype SIGNED_INT │
├───────────────────────────┼──────────────────────────────────┤
│SIGNED_LONG │ Datatype SIGNED_LONG │
├───────────────────────────┼──────────────────────────────────┤
│SIGNED_LONG_LONG │ Datatype SIGNED_LONG_LONG │
├───────────────────────────┼──────────────────────────────────┤
│BOOL │ Datatype BOOL │
├───────────────────────────┼──────────────────────────────────┤
│SINT8_T │ Datatype SINT8_T │
├───────────────────────────┼──────────────────────────────────┤
│SINT16_T │ Datatype SINT16_T │
├───────────────────────────┼──────────────────────────────────┤
│SINT32_T │ Datatype SINT32_T │
├───────────────────────────┼──────────────────────────────────┤
│SINT64_T │ Datatype SINT64_T │
├───────────────────────────┼──────────────────────────────────┤
│F_BOOL │ Datatype F_BOOL │
├───────────────────────────┼──────────────────────────────────┤
│F_INT │ Datatype F_INT │
├───────────────────────────┼──────────────────────────────────┤
│F_FLOAT │ Datatype F_FLOAT │
├───────────────────────────┼──────────────────────────────────┤
│F_DOUBLE │ Datatype F_DOUBLE │
├───────────────────────────┼──────────────────────────────────┤
│F_COMPLEX │ Datatype F_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│F_FLOAT_COMPLEX │ Datatype F_FLOAT_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│F_DOUBLE_COMPLEX │ Datatype F_DOUBLE_COMPLEX │
├───────────────────────────┼──────────────────────────────────┤
│REQUEST_NULL │ Request REQUEST_NULL │
├───────────────────────────┼──────────────────────────────────┤
│MESSAGE_NULL │ Message MESSAGE_NULL │
├───────────────────────────┼──────────────────────────────────┤
│MESSAGE_NO_PROC │ Message MESSAGE_NO_PROC │
├───────────────────────────┼──────────────────────────────────┤
│OP_NULL │ Op OP_NULL │
├───────────────────────────┼──────────────────────────────────┤
│MAX │ Op MAX │
├───────────────────────────┼──────────────────────────────────┤
│MIN │ Op MIN │
├───────────────────────────┼──────────────────────────────────┤
│SUM │ Op SUM │
├───────────────────────────┼──────────────────────────────────┤
│PROD │ Op PROD │
├───────────────────────────┼──────────────────────────────────┤
│LAND │ Op LAND │
├───────────────────────────┼──────────────────────────────────┤
│BAND │ Op BAND │
├───────────────────────────┼──────────────────────────────────┤
│LOR │ Op LOR │
├───────────────────────────┼──────────────────────────────────┤
│BOR │ Op BOR │
├───────────────────────────┼──────────────────────────────────┤
│LXOR │ Op LXOR │
├───────────────────────────┼──────────────────────────────────┤
│BXOR │ Op BXOR │
├───────────────────────────┼──────────────────────────────────┤
│MAXLOC │ Op MAXLOC │
├───────────────────────────┼──────────────────────────────────┤
│MINLOC │ Op MINLOC │
├───────────────────────────┼──────────────────────────────────┤
│REPLACE │ Op REPLACE │
├───────────────────────────┼──────────────────────────────────┤
│NO_OP │ Op NO_OP │
├───────────────────────────┼──────────────────────────────────┤
│GROUP_NULL │ Group GROUP_NULL │
├───────────────────────────┼──────────────────────────────────┤
│GROUP_EMPTY │ Group GROUP_EMPTY │
├───────────────────────────┼──────────────────────────────────┤
│INFO_NULL │ Info INFO_NULL │
├───────────────────────────┼──────────────────────────────────┤
│INFO_ENV │ Info INFO_ENV │
├───────────────────────────┼──────────────────────────────────┤
│ERRHANDLER_NULL │ Errhandler ERRHANDLER_NULL │
├───────────────────────────┼──────────────────────────────────┤
│ERRORS_RETURN │ Errhandler ERRORS_RETURN │
├───────────────────────────┼──────────────────────────────────┤
│ERRORS_ARE_FATAL │ Errhandler ERRORS_ARE_FATAL │
├───────────────────────────┼──────────────────────────────────┤
│COMM_NULL │ Comm COMM_NULL │
├───────────────────────────┼──────────────────────────────────┤
│COMM_SELF │ Intracomm COMM_SELF │
├───────────────────────────┼──────────────────────────────────┤
│COMM_WORLD │ Intracomm COMM_WORLD │
├───────────────────────────┼──────────────────────────────────┤
│WIN_NULL │ Win WIN_NULL │
├───────────────────────────┼──────────────────────────────────┤
│FILE_NULL │ File FILE_NULL │
├───────────────────────────┼──────────────────────────────────┤
│pickle │ Pickle pickle │
└───────────────────────────┴──────────────────────────────────┘
mpi4py.MPI.UNDEFINED
mpi4py.MPI.UNDEFINED: int = UNDEFINED
int UNDEFINED
mpi4py.MPI.ANY_SOURCE
mpi4py.MPI.ANY_SOURCE: int = ANY_SOURCE
int ANY_SOURCE
mpi4py.MPI.ANY_TAG
mpi4py.MPI.ANY_TAG: int = ANY_TAG
int ANY_TAG
mpi4py.MPI.PROC_NULL
mpi4py.MPI.PROC_NULL: int = PROC_NULL
int PROC_NULL
mpi4py.MPI.ROOT
mpi4py.MPI.ROOT: int = ROOT
int ROOT
mpi4py.MPI.BOTTOM
mpi4py.MPI.BOTTOM: Bottom = BOTTOM
Bottom BOTTOM
mpi4py.MPI.IN_PLACE
mpi4py.MPI.IN_PLACE: InPlace = IN_PLACE
InPlace IN_PLACE
mpi4py.MPI.KEYVAL_INVALID
mpi4py.MPI.KEYVAL_INVALID: int = KEYVAL_INVALID
int KEYVAL_INVALID
mpi4py.MPI.TAG_UB
mpi4py.MPI.TAG_UB: int = TAG_UB
int TAG_UB
mpi4py.MPI.HOST
mpi4py.MPI.HOST: int = HOST
int HOST
mpi4py.MPI.IO
mpi4py.MPI.IO: int = IO
int IO
mpi4py.MPI.WTIME_IS_GLOBAL
mpi4py.MPI.WTIME_IS_GLOBAL: int = WTIME_IS_GLOBAL
int WTIME_IS_GLOBAL
mpi4py.MPI.UNIVERSE_SIZE
mpi4py.MPI.UNIVERSE_SIZE: int = UNIVERSE_SIZE
int UNIVERSE_SIZE
mpi4py.MPI.APPNUM
mpi4py.MPI.APPNUM: int = APPNUM
int APPNUM
mpi4py.MPI.LASTUSEDCODE
mpi4py.MPI.LASTUSEDCODE: int = LASTUSEDCODE
int LASTUSEDCODE
mpi4py.MPI.WIN_BASE
mpi4py.MPI.WIN_BASE: int = WIN_BASE
int WIN_BASE
mpi4py.MPI.WIN_SIZE
mpi4py.MPI.WIN_SIZE: int = WIN_SIZE
int WIN_SIZE
mpi4py.MPI.WIN_DISP_UNIT
mpi4py.MPI.WIN_DISP_UNIT: int = WIN_DISP_UNIT
int WIN_DISP_UNIT
mpi4py.MPI.WIN_CREATE_FLAVOR
mpi4py.MPI.WIN_CREATE_FLAVOR: int = WIN_CREATE_FLAVOR
int WIN_CREATE_FLAVOR
mpi4py.MPI.WIN_FLAVOR
mpi4py.MPI.WIN_FLAVOR: int = WIN_FLAVOR
int WIN_FLAVOR
mpi4py.MPI.WIN_MODEL
mpi4py.MPI.WIN_MODEL: int = WIN_MODEL
int WIN_MODEL
mpi4py.MPI.SUCCESS
mpi4py.MPI.SUCCESS: int = SUCCESS
int SUCCESS
mpi4py.MPI.ERR_LASTCODE
mpi4py.MPI.ERR_LASTCODE: int = ERR_LASTCODE
int ERR_LASTCODE
mpi4py.MPI.ERR_COMM
mpi4py.MPI.ERR_COMM: int = ERR_COMM
int ERR_COMM
mpi4py.MPI.ERR_GROUP
mpi4py.MPI.ERR_GROUP: int = ERR_GROUP
int ERR_GROUP
mpi4py.MPI.ERR_TYPE
mpi4py.MPI.ERR_TYPE: int = ERR_TYPE
int ERR_TYPE
mpi4py.MPI.ERR_REQUEST
mpi4py.MPI.ERR_REQUEST: int = ERR_REQUEST
int ERR_REQUEST
mpi4py.MPI.ERR_OP
mpi4py.MPI.ERR_OP: int = ERR_OP
int ERR_OP
mpi4py.MPI.ERR_BUFFER
mpi4py.MPI.ERR_BUFFER: int = ERR_BUFFER
int ERR_BUFFER
mpi4py.MPI.ERR_COUNT
mpi4py.MPI.ERR_COUNT: int = ERR_COUNT
int ERR_COUNT
mpi4py.MPI.ERR_TAG
mpi4py.MPI.ERR_TAG: int = ERR_TAG
int ERR_TAG
mpi4py.MPI.ERR_RANK
mpi4py.MPI.ERR_RANK: int = ERR_RANK
int ERR_RANK
mpi4py.MPI.ERR_ROOT
mpi4py.MPI.ERR_ROOT: int = ERR_ROOT
int ERR_ROOT
mpi4py.MPI.ERR_TRUNCATE
mpi4py.MPI.ERR_TRUNCATE: int = ERR_TRUNCATE
int ERR_TRUNCATE
mpi4py.MPI.ERR_IN_STATUS
mpi4py.MPI.ERR_IN_STATUS: int = ERR_IN_STATUS
int ERR_IN_STATUS
mpi4py.MPI.ERR_PENDING
mpi4py.MPI.ERR_PENDING: int = ERR_PENDING
int ERR_PENDING
mpi4py.MPI.ERR_TOPOLOGY
mpi4py.MPI.ERR_TOPOLOGY: int = ERR_TOPOLOGY
int ERR_TOPOLOGY
mpi4py.MPI.ERR_DIMS
mpi4py.MPI.ERR_DIMS: int = ERR_DIMS
int ERR_DIMS
mpi4py.MPI.ERR_ARG
mpi4py.MPI.ERR_ARG: int = ERR_ARG
int ERR_ARG
mpi4py.MPI.ERR_OTHER
mpi4py.MPI.ERR_OTHER: int = ERR_OTHER
int ERR_OTHER
mpi4py.MPI.ERR_UNKNOWN
mpi4py.MPI.ERR_UNKNOWN: int = ERR_UNKNOWN
int ERR_UNKNOWN
mpi4py.MPI.ERR_INTERN
mpi4py.MPI.ERR_INTERN: int = ERR_INTERN
int ERR_INTERN
mpi4py.MPI.ERR_INFO
mpi4py.MPI.ERR_INFO: int = ERR_INFO
int ERR_INFO
mpi4py.MPI.ERR_FILE
mpi4py.MPI.ERR_FILE: int = ERR_FILE
int ERR_FILE
mpi4py.MPI.ERR_WIN
mpi4py.MPI.ERR_WIN: int = ERR_WIN
int ERR_WIN
mpi4py.MPI.ERR_KEYVAL
mpi4py.MPI.ERR_KEYVAL: int = ERR_KEYVAL
int ERR_KEYVAL
mpi4py.MPI.ERR_INFO_KEY
mpi4py.MPI.ERR_INFO_KEY: int = ERR_INFO_KEY
int ERR_INFO_KEY
mpi4py.MPI.ERR_INFO_VALUE
mpi4py.MPI.ERR_INFO_VALUE: int = ERR_INFO_VALUE
int ERR_INFO_VALUE
mpi4py.MPI.ERR_INFO_NOKEY
mpi4py.MPI.ERR_INFO_NOKEY: int = ERR_INFO_NOKEY
int ERR_INFO_NOKEY
mpi4py.MPI.ERR_ACCESS
mpi4py.MPI.ERR_ACCESS: int = ERR_ACCESS
int ERR_ACCESS
mpi4py.MPI.ERR_AMODE
mpi4py.MPI.ERR_AMODE: int = ERR_AMODE
int ERR_AMODE
mpi4py.MPI.ERR_BAD_FILE
mpi4py.MPI.ERR_BAD_FILE: int = ERR_BAD_FILE
int ERR_BAD_FILE
mpi4py.MPI.ERR_FILE_EXISTS
mpi4py.MPI.ERR_FILE_EXISTS: int = ERR_FILE_EXISTS
int ERR_FILE_EXISTS
mpi4py.MPI.ERR_FILE_IN_USE
mpi4py.MPI.ERR_FILE_IN_USE: int = ERR_FILE_IN_USE
int ERR_FILE_IN_USE
mpi4py.MPI.ERR_NO_SPACE
mpi4py.MPI.ERR_NO_SPACE: int = ERR_NO_SPACE
int ERR_NO_SPACE
mpi4py.MPI.ERR_NO_SUCH_FILE
mpi4py.MPI.ERR_NO_SUCH_FILE: int = ERR_NO_SUCH_FILE
int ERR_NO_SUCH_FILE
mpi4py.MPI.ERR_IO
mpi4py.MPI.ERR_IO: int = ERR_IO
int ERR_IO
mpi4py.MPI.ERR_READ_ONLY
mpi4py.MPI.ERR_READ_ONLY: int = ERR_READ_ONLY
int ERR_READ_ONLY
mpi4py.MPI.ERR_CONVERSION
mpi4py.MPI.ERR_CONVERSION: int = ERR_CONVERSION
int ERR_CONVERSION
mpi4py.MPI.ERR_DUP_DATAREP
mpi4py.MPI.ERR_DUP_DATAREP: int = ERR_DUP_DATAREP
int ERR_DUP_DATAREP
mpi4py.MPI.ERR_UNSUPPORTED_DATAREP
mpi4py.MPI.ERR_UNSUPPORTED_DATAREP: int = ERR_UNSUPPORTED_DATAREP
int ERR_UNSUPPORTED_DATAREP
mpi4py.MPI.ERR_UNSUPPORTED_OPERATION
mpi4py.MPI.ERR_UNSUPPORTED_OPERATION: int = ERR_UNSUPPORTED_OPERATION
int ERR_UNSUPPORTED_OPERATION
mpi4py.MPI.ERR_NAME
mpi4py.MPI.ERR_NAME: int = ERR_NAME
int ERR_NAME
mpi4py.MPI.ERR_NO_MEM
mpi4py.MPI.ERR_NO_MEM: int = ERR_NO_MEM
int ERR_NO_MEM
mpi4py.MPI.ERR_NOT_SAME
mpi4py.MPI.ERR_NOT_SAME: int = ERR_NOT_SAME
int ERR_NOT_SAME
mpi4py.MPI.ERR_PORT
mpi4py.MPI.ERR_PORT: int = ERR_PORT
int ERR_PORT
mpi4py.MPI.ERR_QUOTA
mpi4py.MPI.ERR_QUOTA: int = ERR_QUOTA
int ERR_QUOTA
mpi4py.MPI.ERR_SERVICE
mpi4py.MPI.ERR_SERVICE: int = ERR_SERVICE
int ERR_SERVICE
mpi4py.MPI.ERR_SPAWN
mpi4py.MPI.ERR_SPAWN: int = ERR_SPAWN
int ERR_SPAWN
mpi4py.MPI.ERR_BASE
mpi4py.MPI.ERR_BASE: int = ERR_BASE
int ERR_BASE
mpi4py.MPI.ERR_SIZE
mpi4py.MPI.ERR_SIZE: int = ERR_SIZE
int ERR_SIZE
mpi4py.MPI.ERR_DISP
mpi4py.MPI.ERR_DISP: int = ERR_DISP
int ERR_DISP
mpi4py.MPI.ERR_ASSERT
mpi4py.MPI.ERR_ASSERT: int = ERR_ASSERT
int ERR_ASSERT
mpi4py.MPI.ERR_LOCKTYPE
mpi4py.MPI.ERR_LOCKTYPE: int = ERR_LOCKTYPE
int ERR_LOCKTYPE
mpi4py.MPI.ERR_RMA_CONFLICT
mpi4py.MPI.ERR_RMA_CONFLICT: int = ERR_RMA_CONFLICT
int ERR_RMA_CONFLICT
mpi4py.MPI.ERR_RMA_SYNC
mpi4py.MPI.ERR_RMA_SYNC: int = ERR_RMA_SYNC
int ERR_RMA_SYNC
mpi4py.MPI.ERR_RMA_RANGE
mpi4py.MPI.ERR_RMA_RANGE: int = ERR_RMA_RANGE
int ERR_RMA_RANGE
mpi4py.MPI.ERR_RMA_ATTACH
mpi4py.MPI.ERR_RMA_ATTACH: int = ERR_RMA_ATTACH
int ERR_RMA_ATTACH
mpi4py.MPI.ERR_RMA_SHARED
mpi4py.MPI.ERR_RMA_SHARED: int = ERR_RMA_SHARED
int ERR_RMA_SHARED
mpi4py.MPI.ERR_RMA_FLAVOR
mpi4py.MPI.ERR_RMA_FLAVOR: int = ERR_RMA_FLAVOR
int ERR_RMA_FLAVOR
mpi4py.MPI.ORDER_C
mpi4py.MPI.ORDER_C: int = ORDER_C
int ORDER_C
mpi4py.MPI.ORDER_FORTRAN
mpi4py.MPI.ORDER_FORTRAN: int = ORDER_FORTRAN
int ORDER_FORTRAN
mpi4py.MPI.ORDER_F
mpi4py.MPI.ORDER_F: int = ORDER_F
int ORDER_F
mpi4py.MPI.TYPECLASS_INTEGER
mpi4py.MPI.TYPECLASS_INTEGER: int = TYPECLASS_INTEGER
int TYPECLASS_INTEGER
mpi4py.MPI.TYPECLASS_REAL
mpi4py.MPI.TYPECLASS_REAL: int = TYPECLASS_REAL
int TYPECLASS_REAL
mpi4py.MPI.TYPECLASS_COMPLEX
mpi4py.MPI.TYPECLASS_COMPLEX: int = TYPECLASS_COMPLEX
int TYPECLASS_COMPLEX
mpi4py.MPI.DISTRIBUTE_NONE
mpi4py.MPI.DISTRIBUTE_NONE: int = DISTRIBUTE_NONE
int DISTRIBUTE_NONE
mpi4py.MPI.DISTRIBUTE_BLOCK
mpi4py.MPI.DISTRIBUTE_BLOCK: int = DISTRIBUTE_BLOCK
int DISTRIBUTE_BLOCK
mpi4py.MPI.DISTRIBUTE_CYCLIC
mpi4py.MPI.DISTRIBUTE_CYCLIC: int = DISTRIBUTE_CYCLIC
int DISTRIBUTE_CYCLIC
mpi4py.MPI.DISTRIBUTE_DFLT_DARG
mpi4py.MPI.DISTRIBUTE_DFLT_DARG: int = DISTRIBUTE_DFLT_DARG
int DISTRIBUTE_DFLT_DARG
mpi4py.MPI.COMBINER_NAMED
mpi4py.MPI.COMBINER_NAMED: int = COMBINER_NAMED
int COMBINER_NAMED
mpi4py.MPI.COMBINER_DUP
mpi4py.MPI.COMBINER_DUP: int = COMBINER_DUP
int COMBINER_DUP
mpi4py.MPI.COMBINER_CONTIGUOUS
mpi4py.MPI.COMBINER_CONTIGUOUS: int = COMBINER_CONTIGUOUS
int COMBINER_CONTIGUOUS
mpi4py.MPI.COMBINER_VECTOR
mpi4py.MPI.COMBINER_VECTOR: int = COMBINER_VECTOR
int COMBINER_VECTOR
mpi4py.MPI.COMBINER_HVECTOR
mpi4py.MPI.COMBINER_HVECTOR: int = COMBINER_HVECTOR
int COMBINER_HVECTOR
mpi4py.MPI.COMBINER_INDEXED
mpi4py.MPI.COMBINER_INDEXED: int = COMBINER_INDEXED
int COMBINER_INDEXED
mpi4py.MPI.COMBINER_HINDEXED
mpi4py.MPI.COMBINER_HINDEXED: int = COMBINER_HINDEXED
int COMBINER_HINDEXED
mpi4py.MPI.COMBINER_INDEXED_BLOCK
mpi4py.MPI.COMBINER_INDEXED_BLOCK: int = COMBINER_INDEXED_BLOCK
int COMBINER_INDEXED_BLOCK
mpi4py.MPI.COMBINER_HINDEXED_BLOCK
mpi4py.MPI.COMBINER_HINDEXED_BLOCK: int = COMBINER_HINDEXED_BLOCK
int COMBINER_HINDEXED_BLOCK
mpi4py.MPI.COMBINER_STRUCT
mpi4py.MPI.COMBINER_STRUCT: int = COMBINER_STRUCT
int COMBINER_STRUCT
mpi4py.MPI.COMBINER_SUBARRAY
mpi4py.MPI.COMBINER_SUBARRAY: int = COMBINER_SUBARRAY
int COMBINER_SUBARRAY
mpi4py.MPI.COMBINER_DARRAY
mpi4py.MPI.COMBINER_DARRAY: int = COMBINER_DARRAY
int COMBINER_DARRAY
mpi4py.MPI.COMBINER_RESIZED
mpi4py.MPI.COMBINER_RESIZED: int = COMBINER_RESIZED
int COMBINER_RESIZED
mpi4py.MPI.COMBINER_F90_REAL
mpi4py.MPI.COMBINER_F90_REAL: int = COMBINER_F90_REAL
int COMBINER_F90_REAL
mpi4py.MPI.COMBINER_F90_COMPLEX
mpi4py.MPI.COMBINER_F90_COMPLEX: int = COMBINER_F90_COMPLEX
int COMBINER_F90_COMPLEX
mpi4py.MPI.COMBINER_F90_INTEGER
mpi4py.MPI.COMBINER_F90_INTEGER: int = COMBINER_F90_INTEGER
int COMBINER_F90_INTEGER
mpi4py.MPI.IDENT
mpi4py.MPI.IDENT: int = IDENT
int IDENT
mpi4py.MPI.CONGRUENT
mpi4py.MPI.CONGRUENT: int = CONGRUENT
int CONGRUENT
mpi4py.MPI.SIMILAR
mpi4py.MPI.SIMILAR: int = SIMILAR
int SIMILAR
mpi4py.MPI.UNEQUAL
mpi4py.MPI.UNEQUAL: int = UNEQUAL
int UNEQUAL
mpi4py.MPI.CART
mpi4py.MPI.CART: int = CART
int CART
mpi4py.MPI.GRAPH
mpi4py.MPI.GRAPH: int = GRAPH
int GRAPH
mpi4py.MPI.DIST_GRAPH
mpi4py.MPI.DIST_GRAPH: int = DIST_GRAPH
int DIST_GRAPH
mpi4py.MPI.UNWEIGHTED
mpi4py.MPI.UNWEIGHTED: int = UNWEIGHTED
int UNWEIGHTED
mpi4py.MPI.WEIGHTS_EMPTY
mpi4py.MPI.WEIGHTS_EMPTY: int = WEIGHTS_EMPTY
int WEIGHTS_EMPTY
mpi4py.MPI.COMM_TYPE_SHARED
mpi4py.MPI.COMM_TYPE_SHARED: int = COMM_TYPE_SHARED
int COMM_TYPE_SHARED
mpi4py.MPI.BSEND_OVERHEAD
mpi4py.MPI.BSEND_OVERHEAD: int = BSEND_OVERHEAD
int BSEND_OVERHEAD
mpi4py.MPI.WIN_FLAVOR_CREATE
mpi4py.MPI.WIN_FLAVOR_CREATE: int = WIN_FLAVOR_CREATE
int WIN_FLAVOR_CREATE
mpi4py.MPI.WIN_FLAVOR_ALLOCATE
mpi4py.MPI.WIN_FLAVOR_ALLOCATE: int = WIN_FLAVOR_ALLOCATE
int WIN_FLAVOR_ALLOCATE
mpi4py.MPI.WIN_FLAVOR_DYNAMIC
mpi4py.MPI.WIN_FLAVOR_DYNAMIC: int = WIN_FLAVOR_DYNAMIC
int WIN_FLAVOR_DYNAMIC
mpi4py.MPI.WIN_FLAVOR_SHARED
mpi4py.MPI.WIN_FLAVOR_SHARED: int = WIN_FLAVOR_SHARED
int WIN_FLAVOR_SHARED
mpi4py.MPI.WIN_SEPARATE
mpi4py.MPI.WIN_SEPARATE: int = WIN_SEPARATE
int WIN_SEPARATE
mpi4py.MPI.WIN_UNIFIED
mpi4py.MPI.WIN_UNIFIED: int = WIN_UNIFIED
int WIN_UNIFIED
mpi4py.MPI.MODE_NOCHECK
mpi4py.MPI.MODE_NOCHECK: int = MODE_NOCHECK
int MODE_NOCHECK
mpi4py.MPI.MODE_NOSTORE
mpi4py.MPI.MODE_NOSTORE: int = MODE_NOSTORE
int MODE_NOSTORE
mpi4py.MPI.MODE_NOPUT
mpi4py.MPI.MODE_NOPUT: int = MODE_NOPUT
int MODE_NOPUT
mpi4py.MPI.MODE_NOPRECEDE
mpi4py.MPI.MODE_NOPRECEDE: int = MODE_NOPRECEDE
int MODE_NOPRECEDE
mpi4py.MPI.MODE_NOSUCCEED
mpi4py.MPI.MODE_NOSUCCEED: int = MODE_NOSUCCEED
int MODE_NOSUCCEED
mpi4py.MPI.LOCK_EXCLUSIVE
mpi4py.MPI.LOCK_EXCLUSIVE: int = LOCK_EXCLUSIVE
int LOCK_EXCLUSIVE
mpi4py.MPI.LOCK_SHARED
mpi4py.MPI.LOCK_SHARED: int = LOCK_SHARED
int LOCK_SHARED
mpi4py.MPI.MODE_RDONLY
mpi4py.MPI.MODE_RDONLY: int = MODE_RDONLY
int MODE_RDONLY
mpi4py.MPI.MODE_WRONLY
mpi4py.MPI.MODE_WRONLY: int = MODE_WRONLY
int MODE_WRONLY
mpi4py.MPI.MODE_RDWR
mpi4py.MPI.MODE_RDWR: int = MODE_RDWR
int MODE_RDWR
mpi4py.MPI.MODE_CREATE
mpi4py.MPI.MODE_CREATE: int = MODE_CREATE
int MODE_CREATE
mpi4py.MPI.MODE_EXCL
mpi4py.MPI.MODE_EXCL: int = MODE_EXCL
int MODE_EXCL
mpi4py.MPI.MODE_DELETE_ON_CLOSE
mpi4py.MPI.MODE_DELETE_ON_CLOSE: int = MODE_DELETE_ON_CLOSE
int MODE_DELETE_ON_CLOSE
mpi4py.MPI.MODE_UNIQUE_OPEN
mpi4py.MPI.MODE_UNIQUE_OPEN: int = MODE_UNIQUE_OPEN
int MODE_UNIQUE_OPEN
mpi4py.MPI.MODE_SEQUENTIAL
mpi4py.MPI.MODE_SEQUENTIAL: int = MODE_SEQUENTIAL
int MODE_SEQUENTIAL
mpi4py.MPI.MODE_APPEND
mpi4py.MPI.MODE_APPEND: int = MODE_APPEND
int MODE_APPEND
mpi4py.MPI.SEEK_SET
mpi4py.MPI.SEEK_SET: int = SEEK_SET
int SEEK_SET
mpi4py.MPI.SEEK_CUR
mpi4py.MPI.SEEK_CUR: int = SEEK_CUR
int SEEK_CUR
mpi4py.MPI.SEEK_END
mpi4py.MPI.SEEK_END: int = SEEK_END
int SEEK_END
mpi4py.MPI.DISPLACEMENT_CURRENT
mpi4py.MPI.DISPLACEMENT_CURRENT: int = DISPLACEMENT_CURRENT
int DISPLACEMENT_CURRENT
mpi4py.MPI.DISP_CUR
mpi4py.MPI.DISP_CUR: int = DISP_CUR
int DISP_CUR
mpi4py.MPI.THREAD_SINGLE
mpi4py.MPI.THREAD_SINGLE: int = THREAD_SINGLE
int THREAD_SINGLE
mpi4py.MPI.THREAD_FUNNELED
mpi4py.MPI.THREAD_FUNNELED: int = THREAD_FUNNELED
int THREAD_FUNNELED
mpi4py.MPI.THREAD_SERIALIZED
mpi4py.MPI.THREAD_SERIALIZED: int = THREAD_SERIALIZED
int THREAD_SERIALIZED
mpi4py.MPI.THREAD_MULTIPLE
mpi4py.MPI.THREAD_MULTIPLE: int = THREAD_MULTIPLE
int THREAD_MULTIPLE
mpi4py.MPI.VERSION
mpi4py.MPI.VERSION: int = VERSION
int VERSION
mpi4py.MPI.SUBVERSION
mpi4py.MPI.SUBVERSION: int = SUBVERSION
int SUBVERSION
mpi4py.MPI.MAX_PROCESSOR_NAME
mpi4py.MPI.MAX_PROCESSOR_NAME: int = MAX_PROCESSOR_NAME
int MAX_PROCESSOR_NAME
mpi4py.MPI.MAX_ERROR_STRING
mpi4py.MPI.MAX_ERROR_STRING: int = MAX_ERROR_STRING
int MAX_ERROR_STRING
mpi4py.MPI.MAX_PORT_NAME
mpi4py.MPI.MAX_PORT_NAME: int = MAX_PORT_NAME
int MAX_PORT_NAME
mpi4py.MPI.MAX_INFO_KEY
mpi4py.MPI.MAX_INFO_KEY: int = MAX_INFO_KEY
int MAX_INFO_KEY
mpi4py.MPI.MAX_INFO_VAL
mpi4py.MPI.MAX_INFO_VAL: int = MAX_INFO_VAL
int MAX_INFO_VAL
mpi4py.MPI.MAX_OBJECT_NAME
mpi4py.MPI.MAX_OBJECT_NAME: int = MAX_OBJECT_NAME
int MAX_OBJECT_NAME
mpi4py.MPI.MAX_DATAREP_STRING
mpi4py.MPI.MAX_DATAREP_STRING: int = MAX_DATAREP_STRING
int MAX_DATAREP_STRING
mpi4py.MPI.MAX_LIBRARY_VERSION_STRING
mpi4py.MPI.MAX_LIBRARY_VERSION_STRING: int = MAX_LIBRARY_VERSION_STRING
int MAX_LIBRARY_VERSION_STRING
mpi4py.MPI.DATATYPE_NULL
mpi4py.MPI.DATATYPE_NULL: Datatype = DATATYPE_NULL
Datatype DATATYPE_NULL
mpi4py.MPI.UB
mpi4py.MPI.UB: Datatype = UB
Datatype UB
mpi4py.MPI.LB
mpi4py.MPI.LB: Datatype = LB
Datatype LB
mpi4py.MPI.PACKED
mpi4py.MPI.PACKED: Datatype = PACKED
Datatype PACKED
mpi4py.MPI.BYTE
mpi4py.MPI.BYTE: Datatype = BYTE
Datatype BYTE
mpi4py.MPI.AINT
mpi4py.MPI.AINT: Datatype = AINT
Datatype AINT
mpi4py.MPI.OFFSET
mpi4py.MPI.OFFSET: Datatype = OFFSET
Datatype OFFSET
mpi4py.MPI.COUNT
mpi4py.MPI.COUNT: Datatype = COUNT
Datatype COUNT
mpi4py.MPI.CHAR
mpi4py.MPI.CHAR: Datatype = CHAR
Datatype CHAR
mpi4py.MPI.WCHAR
mpi4py.MPI.WCHAR: Datatype = WCHAR
Datatype WCHAR
mpi4py.MPI.SIGNED_CHAR
mpi4py.MPI.SIGNED_CHAR: Datatype = SIGNED_CHAR
Datatype SIGNED_CHAR
mpi4py.MPI.SHORT
mpi4py.MPI.SHORT: Datatype = SHORT
Datatype SHORT
mpi4py.MPI.INT
mpi4py.MPI.INT: Datatype = INT
Datatype INT
mpi4py.MPI.LONG
mpi4py.MPI.LONG: Datatype = LONG
Datatype LONG
mpi4py.MPI.LONG_LONG
mpi4py.MPI.LONG_LONG: Datatype = LONG_LONG
Datatype LONG_LONG
mpi4py.MPI.UNSIGNED_CHAR
mpi4py.MPI.UNSIGNED_CHAR: Datatype = UNSIGNED_CHAR
Datatype UNSIGNED_CHAR
mpi4py.MPI.UNSIGNED_SHORT
mpi4py.MPI.UNSIGNED_SHORT: Datatype = UNSIGNED_SHORT
Datatype UNSIGNED_SHORT
mpi4py.MPI.UNSIGNED
mpi4py.MPI.UNSIGNED: Datatype = UNSIGNED
Datatype UNSIGNED
mpi4py.MPI.UNSIGNED_LONG
mpi4py.MPI.UNSIGNED_LONG: Datatype = UNSIGNED_LONG
Datatype UNSIGNED_LONG
mpi4py.MPI.UNSIGNED_LONG_LONG
mpi4py.MPI.UNSIGNED_LONG_LONG: Datatype = UNSIGNED_LONG_LONG
Datatype UNSIGNED_LONG_LONG
mpi4py.MPI.FLOAT
mpi4py.MPI.FLOAT: Datatype = FLOAT
Datatype FLOAT
mpi4py.MPI.DOUBLE
mpi4py.MPI.DOUBLE: Datatype = DOUBLE
Datatype DOUBLE
mpi4py.MPI.LONG_DOUBLE
mpi4py.MPI.LONG_DOUBLE: Datatype = LONG_DOUBLE
Datatype LONG_DOUBLE
mpi4py.MPI.C_BOOL
mpi4py.MPI.C_BOOL: Datatype = C_BOOL
Datatype C_BOOL
mpi4py.MPI.INT8_T
mpi4py.MPI.INT8_T: Datatype = INT8_T
Datatype INT8_T
mpi4py.MPI.INT16_T
mpi4py.MPI.INT16_T: Datatype = INT16_T
Datatype INT16_T
mpi4py.MPI.INT32_T
mpi4py.MPI.INT32_T: Datatype = INT32_T
Datatype INT32_T
mpi4py.MPI.INT64_T
mpi4py.MPI.INT64_T: Datatype = INT64_T
Datatype INT64_T
mpi4py.MPI.UINT8_T
mpi4py.MPI.UINT8_T: Datatype = UINT8_T
Datatype UINT8_T
mpi4py.MPI.UINT16_T
mpi4py.MPI.UINT16_T: Datatype = UINT16_T
Datatype UINT16_T
mpi4py.MPI.UINT32_T
mpi4py.MPI.UINT32_T: Datatype = UINT32_T
Datatype UINT32_T
mpi4py.MPI.UINT64_T
mpi4py.MPI.UINT64_T: Datatype = UINT64_T
Datatype UINT64_T
mpi4py.MPI.C_COMPLEX
mpi4py.MPI.C_COMPLEX: Datatype = C_COMPLEX
Datatype C_COMPLEX
mpi4py.MPI.C_FLOAT_COMPLEX
mpi4py.MPI.C_FLOAT_COMPLEX: Datatype = C_FLOAT_COMPLEX
Datatype C_FLOAT_COMPLEX
mpi4py.MPI.C_DOUBLE_COMPLEX
mpi4py.MPI.C_DOUBLE_COMPLEX: Datatype = C_DOUBLE_COMPLEX
Datatype C_DOUBLE_COMPLEX
mpi4py.MPI.C_LONG_DOUBLE_COMPLEX
mpi4py.MPI.C_LONG_DOUBLE_COMPLEX: Datatype = C_LONG_DOUBLE_COMPLEX
Datatype C_LONG_DOUBLE_COMPLEX
mpi4py.MPI.CXX_BOOL
mpi4py.MPI.CXX_BOOL: Datatype = CXX_BOOL
Datatype CXX_BOOL
mpi4py.MPI.CXX_FLOAT_COMPLEX
mpi4py.MPI.CXX_FLOAT_COMPLEX: Datatype = CXX_FLOAT_COMPLEX
Datatype CXX_FLOAT_COMPLEX
mpi4py.MPI.CXX_DOUBLE_COMPLEX
mpi4py.MPI.CXX_DOUBLE_COMPLEX: Datatype = CXX_DOUBLE_COMPLEX
Datatype CXX_DOUBLE_COMPLEX
mpi4py.MPI.CXX_LONG_DOUBLE_COMPLEX
mpi4py.MPI.CXX_LONG_DOUBLE_COMPLEX: Datatype = CXX_LONG_DOUBLE_COMPLEX
Datatype CXX_LONG_DOUBLE_COMPLEX
mpi4py.MPI.SHORT_INT
mpi4py.MPI.SHORT_INT: Datatype = SHORT_INT
Datatype SHORT_INT
mpi4py.MPI.INT_INT
mpi4py.MPI.INT_INT: Datatype = INT_INT
Datatype INT_INT
mpi4py.MPI.TWOINT
mpi4py.MPI.TWOINT: Datatype = TWOINT
Datatype TWOINT
mpi4py.MPI.LONG_INT
mpi4py.MPI.LONG_INT: Datatype = LONG_INT
Datatype LONG_INT
mpi4py.MPI.FLOAT_INT
mpi4py.MPI.FLOAT_INT: Datatype = FLOAT_INT
Datatype FLOAT_INT
mpi4py.MPI.DOUBLE_INT
mpi4py.MPI.DOUBLE_INT: Datatype = DOUBLE_INT
Datatype DOUBLE_INT
mpi4py.MPI.LONG_DOUBLE_INT
mpi4py.MPI.LONG_DOUBLE_INT: Datatype = LONG_DOUBLE_INT
Datatype LONG_DOUBLE_INT
mpi4py.MPI.CHARACTER
mpi4py.MPI.CHARACTER: Datatype = CHARACTER
Datatype CHARACTER
mpi4py.MPI.LOGICAL
mpi4py.MPI.LOGICAL: Datatype = LOGICAL
Datatype LOGICAL
mpi4py.MPI.INTEGER
mpi4py.MPI.INTEGER: Datatype = INTEGER
Datatype INTEGER
mpi4py.MPI.REAL
mpi4py.MPI.REAL: Datatype = REAL
Datatype REAL
mpi4py.MPI.DOUBLE_PRECISION
mpi4py.MPI.DOUBLE_PRECISION: Datatype = DOUBLE_PRECISION
Datatype DOUBLE_PRECISION
mpi4py.MPI.COMPLEX
mpi4py.MPI.COMPLEX: Datatype = COMPLEX
Datatype COMPLEX
mpi4py.MPI.DOUBLE_COMPLEX
mpi4py.MPI.DOUBLE_COMPLEX: Datatype = DOUBLE_COMPLEX
Datatype DOUBLE_COMPLEX
mpi4py.MPI.LOGICAL1
mpi4py.MPI.LOGICAL1: Datatype = LOGICAL1
Datatype LOGICAL1
mpi4py.MPI.LOGICAL2
mpi4py.MPI.LOGICAL2: Datatype = LOGICAL2
Datatype LOGICAL2
mpi4py.MPI.LOGICAL4
mpi4py.MPI.LOGICAL4: Datatype = LOGICAL4
Datatype LOGICAL4
mpi4py.MPI.LOGICAL8
mpi4py.MPI.LOGICAL8: Datatype = LOGICAL8
Datatype LOGICAL8
mpi4py.MPI.INTEGER1
mpi4py.MPI.INTEGER1: Datatype = INTEGER1
Datatype INTEGER1
mpi4py.MPI.INTEGER2
mpi4py.MPI.INTEGER2: Datatype = INTEGER2
Datatype INTEGER2
mpi4py.MPI.INTEGER4
mpi4py.MPI.INTEGER4: Datatype = INTEGER4
Datatype INTEGER4
mpi4py.MPI.INTEGER8
mpi4py.MPI.INTEGER8: Datatype = INTEGER8
Datatype INTEGER8
mpi4py.MPI.INTEGER16
mpi4py.MPI.INTEGER16: Datatype = INTEGER16
Datatype INTEGER16
mpi4py.MPI.REAL2
mpi4py.MPI.REAL2: Datatype = REAL2
Datatype REAL2
mpi4py.MPI.REAL4
mpi4py.MPI.REAL4: Datatype = REAL4
Datatype REAL4
mpi4py.MPI.REAL8
mpi4py.MPI.REAL8: Datatype = REAL8
Datatype REAL8
mpi4py.MPI.REAL16
mpi4py.MPI.REAL16: Datatype = REAL16
Datatype REAL16
mpi4py.MPI.COMPLEX4
mpi4py.MPI.COMPLEX4: Datatype = COMPLEX4
Datatype COMPLEX4
mpi4py.MPI.COMPLEX8
mpi4py.MPI.COMPLEX8: Datatype = COMPLEX8
Datatype COMPLEX8
mpi4py.MPI.COMPLEX16
mpi4py.MPI.COMPLEX16: Datatype = COMPLEX16
Datatype COMPLEX16
mpi4py.MPI.COMPLEX32
mpi4py.MPI.COMPLEX32: Datatype = COMPLEX32
Datatype COMPLEX32
mpi4py.MPI.UNSIGNED_INT
mpi4py.MPI.UNSIGNED_INT: Datatype = UNSIGNED_INT
Datatype UNSIGNED_INT
mpi4py.MPI.SIGNED_SHORT
mpi4py.MPI.SIGNED_SHORT: Datatype = SIGNED_SHORT
Datatype SIGNED_SHORT
mpi4py.MPI.SIGNED_INT
mpi4py.MPI.SIGNED_INT: Datatype = SIGNED_INT
Datatype SIGNED_INT
mpi4py.MPI.SIGNED_LONG
mpi4py.MPI.SIGNED_LONG: Datatype = SIGNED_LONG
Datatype SIGNED_LONG
mpi4py.MPI.SIGNED_LONG_LONG
mpi4py.MPI.SIGNED_LONG_LONG: Datatype = SIGNED_LONG_LONG
Datatype SIGNED_LONG_LONG
mpi4py.MPI.BOOL
mpi4py.MPI.BOOL: Datatype = BOOL
Datatype BOOL
mpi4py.MPI.SINT8_T
mpi4py.MPI.SINT8_T: Datatype = SINT8_T
Datatype SINT8_T
mpi4py.MPI.SINT16_T
mpi4py.MPI.SINT16_T: Datatype = SINT16_T
Datatype SINT16_T
mpi4py.MPI.SINT32_T
mpi4py.MPI.SINT32_T: Datatype = SINT32_T
Datatype SINT32_T
mpi4py.MPI.SINT64_T
mpi4py.MPI.SINT64_T: Datatype = SINT64_T
Datatype SINT64_T
mpi4py.MPI.F_BOOL
mpi4py.MPI.F_BOOL: Datatype = F_BOOL
Datatype F_BOOL
mpi4py.MPI.F_INT
mpi4py.MPI.F_INT: Datatype = F_INT
Datatype F_INT
mpi4py.MPI.F_FLOAT
mpi4py.MPI.F_FLOAT: Datatype = F_FLOAT
Datatype F_FLOAT
mpi4py.MPI.F_DOUBLE
mpi4py.MPI.F_DOUBLE: Datatype = F_DOUBLE
Datatype F_DOUBLE
mpi4py.MPI.F_COMPLEX
mpi4py.MPI.F_COMPLEX: Datatype = F_COMPLEX
Datatype F_COMPLEX
mpi4py.MPI.F_FLOAT_COMPLEX
mpi4py.MPI.F_FLOAT_COMPLEX: Datatype = F_FLOAT_COMPLEX
Datatype F_FLOAT_COMPLEX
mpi4py.MPI.F_DOUBLE_COMPLEX
mpi4py.MPI.F_DOUBLE_COMPLEX: Datatype = F_DOUBLE_COMPLEX
Datatype F_DOUBLE_COMPLEX
mpi4py.MPI.REQUEST_NULL
mpi4py.MPI.REQUEST_NULL: Request = REQUEST_NULL
Request REQUEST_NULL
mpi4py.MPI.MESSAGE_NULL
mpi4py.MPI.MESSAGE_NULL: Message = MESSAGE_NULL
Message MESSAGE_NULL
mpi4py.MPI.MESSAGE_NO_PROC
mpi4py.MPI.MESSAGE_NO_PROC: Message = MESSAGE_NO_PROC
Message MESSAGE_NO_PROC
mpi4py.MPI.OP_NULL
mpi4py.MPI.OP_NULL: Op = OP_NULL
Op OP_NULL
Parameters
• x (Any)
• y (Any)
Return type
Any
mpi4py.MPI.MAX
mpi4py.MPI.MAX: Op = MAX
Op MAX
Parameters
• x (Any)
• y (Any)
Return type
Any
mpi4py.MPI.MIN
mpi4py.MPI.MIN: Op = MIN
Op MIN
Parameters
• x (Any)
• y (Any)
Return type
Any
mpi4py.MPI.SUM
mpi4py.MPI.SUM: Op = SUM
Op SUM
Parameters
• x (Any)
• y (Any)
Return type
Any
mpi4py.MPI.PROD
mpi4py.MPI.PROD: Op = PROD
Op PROD
Parameters
• x (Any)
• y (Any)
Return type
Any
mpi4py.MPI.LAND
mpi4py.MPI.LAND: Op = LAND
Op LAND
Parameters
• x (Any)
• y (Any)
Return type
Any
mpi4py.MPI.BAND
mpi4py.MPI.BAND: Op = BAND
Op BAND
Parameters
• x (Any)
• y (Any)
Return type
Any
mpi4py.MPI.LOR
mpi4py.MPI.LOR: Op = LOR
Op LOR
Parameters
• x (Any)
• y (Any)
Return type
Any
mpi4py.MPI.BOR
mpi4py.MPI.BOR: Op = BOR
Op BOR
Parameters
• x (Any)
• y (Any)
Return type
Any
mpi4py.MPI.LXOR
mpi4py.MPI.LXOR: Op = LXOR
Op LXOR
Parameters
• x (Any)
• y (Any)
Return type
Any
mpi4py.MPI.BXOR
mpi4py.MPI.BXOR: Op = BXOR
Op BXOR
Parameters
• x (Any)
• y (Any)
Return type
Any
mpi4py.MPI.MAXLOC
mpi4py.MPI.MAXLOC: Op = MAXLOC
Op MAXLOC
Parameters
• x (Any)
• y (Any)
Return type
Any
mpi4py.MPI.MINLOC
mpi4py.MPI.MINLOC: Op = MINLOC
Op MINLOC
Parameters
• x (Any)
• y (Any)
Return type
Any
mpi4py.MPI.REPLACE
mpi4py.MPI.REPLACE: Op = REPLACE
Op REPLACE
Parameters
• x (Any)
• y (Any)
Return type
Any
mpi4py.MPI.NO_OP
mpi4py.MPI.NO_OP: Op = NO_OP
Op NO_OP
Parameters
• x (Any)
• y (Any)
Return type
Any
mpi4py.MPI.GROUP_NULL
mpi4py.MPI.GROUP_NULL: Group = GROUP_NULL
Group GROUP_NULL
mpi4py.MPI.GROUP_EMPTY
mpi4py.MPI.GROUP_EMPTY: Group = GROUP_EMPTY
Group GROUP_EMPTY
mpi4py.MPI.INFO_NULL
mpi4py.MPI.INFO_NULL: Info = INFO_NULL
Info INFO_NULL
mpi4py.MPI.INFO_ENV
mpi4py.MPI.INFO_ENV: Info = INFO_ENV
Info INFO_ENV
mpi4py.MPI.ERRHANDLER_NULL
mpi4py.MPI.ERRHANDLER_NULL: Errhandler = ERRHANDLER_NULL
Errhandler ERRHANDLER_NULL
mpi4py.MPI.ERRORS_RETURN
mpi4py.MPI.ERRORS_RETURN: Errhandler = ERRORS_RETURN
Errhandler ERRORS_RETURN
mpi4py.MPI.ERRORS_ARE_FATAL
mpi4py.MPI.ERRORS_ARE_FATAL: Errhandler = ERRORS_ARE_FATAL
Errhandler ERRORS_ARE_FATAL
mpi4py.MPI.COMM_NULL
mpi4py.MPI.COMM_NULL: Comm = COMM_NULL
Comm COMM_NULL
mpi4py.MPI.COMM_SELF
mpi4py.MPI.COMM_SELF: Intracomm = COMM_SELF
Intracomm COMM_SELF
mpi4py.MPI.COMM_WORLD
mpi4py.MPI.COMM_WORLD: Intracomm = COMM_WORLD
Intracomm COMM_WORLD
mpi4py.MPI.WIN_NULL
mpi4py.MPI.WIN_NULL: Win = WIN_NULL
Win WIN_NULL
mpi4py.MPI.FILE_NULL
mpi4py.MPI.FILE_NULL: File = FILE_NULL
File FILE_NULL
mpi4py.MPI.pickle
mpi4py.MPI.pickle: Pickle = <mpi4py.MPI.Pickle object>
Pickle pickle
CITATION
If MPI for Python been significant to a project that leads to an academic publication,
please acknowledge that fact by citing the project.
• L. Dalcin and Y.-L. L. Fang, mpi4py: Status Update After 12 Years of Development,
Computing in Science & Engineering, 23(4):47-54, 2021. ‐
https://doi.org/10.1109/MCSE.2021.3083216
• L. Dalcin, P. Kler, R. Paz, and A. Cosimo, Parallel Distributed Computing using Python,
Advances in Water Resources, 34(9):1124-1139, 2011. ‐
https://doi.org/10.1016/j.advwatres.2011.04.013
• L. Dalcin, R. Paz, M. Storti, and J. D’Elia, MPI for Python: performance improvements
and MPI-2 extensions, Journal of Parallel and Distributed Computing, 68(5):655-662,
2008. https://doi.org/10.1016/j.jpdc.2007.09.005
• L. Dalcin, R. Paz, and M. Storti, MPI for Python, Journal of Parallel and Distributed
Computing, 65(9):1108-1115, 2005. https://doi.org/10.1016/j.jpdc.2005.03.010
INSTALLATION
Requirements
You need to have the following software properly installed in order to build MPI for
Python:
• A working MPI implementation, preferably supporting MPI-3 and built with shared/dynamic
libraries.
NOTE:
If you want to build some MPI implementation from sources, check the instructions at
Building MPI from sources in the appendix.
• Python 2.7, 3.5 or above.
NOTE:
Some MPI-1 implementations do require the actual command line arguments to be passed
in MPI_Init(). In this case, you will need to use a rebuilt, MPI-enabled, Python
interpreter executable. MPI for Python has some support for alleviating you from this
task. Check the instructions at MPI-enabled Python interpreter in the appendix.
Using pip
If you already have a working MPI (either if you installed it from sources or by using a
pre-built package from your favourite GNU/Linux distribution) and the mpicc compiler
wrapper is on your search path, you can use pip:
$ python -m pip install mpi4py
NOTE:
If the mpicc compiler wrapper is not on your search path (or if it has a different
name) you can use env to pass the environment variable MPICC providing the full path to
the MPI compiler wrapper executable:
$ env MPICC=/path/to/mpicc python -m pip install mpi4py
WARNING:
pip keeps previouly built wheel files on its cache for future reuse. If you want to
reinstall the mpi4py package using a different or updated MPI implementation, you have
to either first remove the cached wheel file with:
$ python -m pip cache remove mpi4py
or ask pip to disable the cache:
$ python -m pip install --no-cache-dir mpi4py
Using distutils
The MPI for Python package is available for download at the project website generously
hosted by GitHub. You can use curl or wget to get a release tarball.
• Using curl:
$ curl -O https://github.com/mpi4py/mpi4py/releases/download/X.Y.Z/mpi4py-X.Y.Z.tar.gz
• Using wget:
$ wget https://github.com/mpi4py/mpi4py/releases/download/X.Y.Z/mpi4py-X.Y.Z.tar.gz
After unpacking the release tarball:
$ tar -zxf mpi4py-X.Y.Z.tar.gz
$ cd mpi4py-X.Y.Z
the package is ready for building.
MPI for Python uses a standard distutils-based build system. However, some distutils
commands (like build) have additional options:
--mpicc=
Lets you specify a special location or name for the mpicc compiler wrapper.
--mpi= Lets you pass a section with MPI configuration within a special configuration file.
--configure
Runs exhaustive tests for checking about missing MPI types, constants, and
functions. This option should be passed in order to build MPI for Python against
old MPI-1 or MPI-2 implementations, possibly providing a subset of MPI-3.
If you use a MPI implementation providing a mpicc compiler wrapper (e.g., MPICH, Open
MPI), it will be used for compilation and linking. This is the preferred and easiest way
of building MPI for Python.
If mpicc is located somewhere in your search path, simply run the build command:
$ python setup.py build
If mpicc is not in your search path or the compiler wrapper has a different name, you can
run the build command specifying its location:
$ python setup.py build --mpicc=/where/you/have/mpicc
Alternatively, you can provide all the relevant information about your MPI implementation
by editing the file called mpi.cfg. You can use the default section [mpi] or add a new,
custom section, for example [other_mpi] (see the examples provided in the mpi.cfg file as
a starting point to write your own section):
[mpi]
include_dirs = /usr/local/mpi/include
libraries = mpi
library_dirs = /usr/local/mpi/lib
runtime_library_dirs = /usr/local/mpi/lib
[other_mpi]
include_dirs = /opt/mpi/include ...
libraries = mpi ...
library_dirs = /opt/mpi/lib ...
runtime_library_dirs = /op/mpi/lib ...
...
and then run the build command, perhaps specifying you custom configuration section:
$ python setup.py build --mpi=other_mpi
After building, the package is ready for install.
If you have root privileges (either by log-in as the root user of by using sudo) and you
want to install MPI for Python in your system for all users, just do:
$ python setup.py install
The previous steps will install the mpi4py package at standard location
prefix/lib/pythonX.X/site-packages.
If you do not have root privileges or you want to install MPI for Python for your private
use, just do:
$ python setup.py install --user
Testing
To quickly test the installation:
$ mpiexec -n 5 python -m mpi4py.bench helloworld
Hello, World! I am process 0 of 5 on localhost.
Hello, World! I am process 1 of 5 on localhost.
Hello, World! I am process 2 of 5 on localhost.
Hello, World! I am process 3 of 5 on localhost.
Hello, World! I am process 4 of 5 on localhost.
If you installed from source, issuing at the command line:
$ mpiexec -n 5 python demo/helloworld.py
or (in the case of ancient MPI-1 implementations):
$ mpirun -np 5 python `pwd`/demo/helloworld.py
will launch a five-process run of the Python interpreter and run the test script
demo/helloworld.py from the source distribution.
You can also run all the unittest scripts:
$ mpiexec -n 5 python test/runtests.py
or, if you have nose unit testing framework installed:
$ mpiexec -n 5 nosetests -w test
or, if you have py.test unit testing framework installed:
$ mpiexec -n 5 py.test test/
APPENDIX
MPI-enabled Python interpreter
WARNING:
These days it is no longer required to use the MPI-enabled Python interpreter in
most cases, and, therefore, it is not built by default anymore because it is too
difficult to reliably build a Python interpreter across different distributions.
If you know that you still really need it, see below on how to use the build_exe
and install_exe commands.
Some MPI-1 implementations (notably, MPICH 1) do require the actual command line arguments
to be passed at the time MPI_Init() is called. In this case, you will need to use a
re-built, MPI-enabled, Python interpreter binary executable. A basic implementation
(targeting Python 2.X) of what is required is shown below:
#include <Python.h>
#include <mpi.h>
int main(int argc, char *argv[])
{
int status, flag;
MPI_Init(&argc, &argv);
status = Py_Main(argc, argv);
MPI_Finalized(&flag);
if (!flag) MPI_Finalize();
return status;
}
The source code above is straightforward; compiling it should also be. However, the
linking step is more tricky: special flags have to be passed to the linker depending on
your platform. In order to alleviate you for such low-level details, MPI for Python
provides some pure-distutils based support to build and install an MPI-enabled Python
interpreter executable:
$ cd mpi4py-X.X.X
$ python setup.py build_exe [--mpi=<name>|--mpicc=/path/to/mpicc]
$ [sudo] python setup.py install_exe [--install-dir=$HOME/bin]
After the above steps you should have the MPI-enabled interpreter installed as
prefix/bin/pythonX.X-mpi (or $HOME/bin/pythonX.X-mpi). Assuming that prefix/bin (or
$HOME/bin) is listed on your PATH, you should be able to enter your MPI-enabled Python
interactively, for example:
$ python2.7-mpi
Python 2.7.8 (default, Nov 10 2014, 08:19:18)
[GCC 4.9.2 20141101 (Red Hat 4.9.2-1)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys.executable
'/usr/bin/python2.7-mpi'
>>>
Building MPI from sources
In the list below you have some executive instructions for building some of the
open-source MPI implementations out there with support for shared/dynamic libraries on
POSIX environments.
• MPICH
$ tar -zxf mpich-X.X.X.tar.gz
$ cd mpich-X.X.X
$ ./configure --enable-shared --prefix=/usr/local/mpich
$ make
$ make install
• Open MPI
$ tar -zxf openmpi-X.X.X tar.gz
$ cd openmpi-X.X.X
$ ./configure --prefix=/usr/local/openmpi
$ make all
$ make install
• MPICH 1
$ tar -zxf mpich-X.X.X.tar.gz
$ cd mpich-X.X.X
$ ./configure --enable-sharedlib --prefix=/usr/local/mpich1
$ make
$ make install
Perhaps you will need to set the LD_LIBRARY_PATH environment variable (using export,
setenv or what applies to your system) pointing to the directory containing the MPI
libraries . In case of getting runtime linking errors when running MPI programs, the
following lines can be added to the user login shell script (.profile, .bashrc, etc.).
• MPICH
MPI_DIR=/usr/local/mpich
export LD_LIBRARY_PATH=$MPI_DIR/lib:$LD_LIBRARY_PATH
• Open MPI
MPI_DIR=/usr/local/openmpi
export LD_LIBRARY_PATH=$MPI_DIR/lib:$LD_LIBRARY_PATH
• MPICH 1
MPI_DIR=/usr/local/mpich1
export LD_LIBRARY_PATH=$MPI_DIR/lib/shared:$LD_LIBRARY_PATH:
export MPICH_USE_SHLIB=yes
WARNING:
MPICH 1 support for dynamic libraries is not completely transparent. Users should set
the environment variable MPICH_USE_SHLIB to yes in order to avoid link problems when
using the mpicc compiler wrapper.
AUTHOR
Lisandro Dalcin
COPYRIGHT
2024, Lisandro Dalcin