plucky (3) MPI_Type_vector.openmpi.3.gz
SYNTAX
C Syntax
#include <mpi.h>
int MPI_Type_vector(int count, int blocklength, int stride,
MPI_Datatype oldtype, MPI_Datatype *newtype)
Fortran Syntax
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_TYPE_VECTOR(COUNT, BLOCKLENGTH, STRIDE, OLDTYPE, NEWTYPE,
IERROR)
INTEGER COUNT, BLOCKLENGTH, STRIDE, OLDTYPE
INTEGER NEWTYPE, IERROR
Fortran 2008 Syntax
USE mpi_f08
MPI_Type_vector(count, blocklength, stride, oldtype, newtype, ierror)
INTEGER, INTENT(IN) :: count, blocklength, stride
TYPE(MPI_Datatype), INTENT(IN) :: oldtype
TYPE(MPI_Datatype), INTENT(OUT) :: newtype
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
INPUT PARAMETERS
• count: Number of blocks (nonnegative integer).
• blocklength: Number of elements in each block (nonnegative integer).
• stride: Number of elements between start of each block (integer).
• oldtype: Old datatype (handle).
OUTPUT PARAMETERS
• newtype: New datatype (handle).
• ierror: Fortran only: Error status (integer).
DESCRIPTION
The function MPI_Type_vector is a general constructor that allows replication of a datatype into
locations that consist of equally spaced blocks. Each block is obtained by concatenating the same number
of copies of the old datatype. The spacing between blocks is a multiple of the extent of the old
datatype.
Example 1: Assume, again, that oldtype has type map {(double, 0), (char, 8)}, with extent 16. A call to
MPI_Type_vector(2, 3, 4, oldtype, newtype) will create the datatype with type map
{(double, 0), (char, 8), (double, 16), (char, 24),
(double, 32), (char, 40),
(double, 64), (char, 72),
(double, 80), (char, 88), (double, 96), (char, 104)}
That is, two blocks with three copies each of the old type, with a stride of 4 elements (4 x 16 bytes)
between the blocks.
Example 2: A call to MPI_Type_vector(3, 1, -2, oldtype, newtype) will create the datatype
{(double, 0), (char, 8), (double, -32), (char, -24),
(double, -64), (char, -56)}
In general, assume that oldtype has type map
{(type(0), disp(0)), ..., (type(n-1), disp(n-1))},
with extent ex. Let bl be the blocklength. The newly created datatype has a type map with count x bl x n
entries:
{(type(0), disp(0)), ..., (type(n-1), disp(n-1)),
(type(0), disp(0) + ex), ..., (type(n-1), disp(n-1) + ex), ...,
(type(0), disp(0) + (bl -1) * ex),...,
(type(n-1), disp(n-1) + (bl -1)* ex),
(type(0), disp(0) + stride * ex),..., (type(n-1),
disp(n-1) + stride * ex), ...,
(type(0), disp(0) + (stride + bl - 1) * ex), ...,
(type(n-1), disp(n-1) + (stride + bl -1) * ex), ...,
(type(0), disp(0) + stride * (count -1) * ex), ...,
(type(n-1), disp(n-1) + stride * (count -1) * ex), ...,
(type(0), disp(0) + (stride * (count -1) + bl -1) * ex), ...,
(type(n-1), disp(n-1) + (stride * (count -1) + bl -1) * ex)}
A call to MPI_Type_contiguous(count, oldtype, newtype) is equivalent to a call to MPI_Type_vector(count,
1, 1, oldtype, newtype), or to a call to MPI_Type_vector(1, count, n, oldtype, newtype), n arbitrary.
ERRORS
Almost all MPI routines return an error value; C routines as the return result of the function and
Fortran routines in the last argument.
Before the error value is returned, the current MPI error handler associated with the communication
object (e.g., communicator, window, file) is called. If no communication object is associated with the
MPI call, then the call is considered attached to MPI_COMM_SELF and will call the associated MPI error
handler. When MPI_COMM_SELF is not initialized (i.e., before MPI_Init/MPI_Init_thread, after
MPI_Finalize, or when using the Sessions Model exclusively) the error raises the initial error handler.
The initial error handler can be changed by calling MPI_Comm_set_errhandler on MPI_COMM_SELF when using
the World model, or the mpi_initial_errhandler CLI argument to mpiexec or info key to MPI_Comm_spawn/‐
MPI_Comm_spawn_multiple. If no other appropriate error handler has been set, then the MPI_ERRORS_RETURN
error handler is called for MPI I/O functions and the MPI_ERRORS_ABORT error handler is called for all
other MPI functions.
Open MPI includes three predefined error handlers that can be used:
• MPI_ERRORS_ARE_FATAL Causes the program to abort all connected MPI processes.
• MPI_ERRORS_ABORT An error handler that can be invoked on a communicator, window, file, or session. When
called on a communicator, it acts as if MPI_Abort was called on that communicator. If called on a
window or file, acts as if MPI_Abort was called on a communicator containing the group of processes in
the corresponding window or file. If called on a session, aborts only the local process.
• MPI_ERRORS_RETURN Returns an error code to the application.
MPI applications can also implement their own error handlers by calling:
• MPI_Comm_create_errhandler then MPI_Comm_set_errhandler
• MPI_File_create_errhandler then MPI_File_set_errhandler
• MPI_Session_create_errhandler then MPI_Session_set_errhandler or at MPI_Session_init
• MPI_Win_create_errhandler then MPI_Win_set_errhandler
Note that MPI does not guarantee that an MPI program can continue past an error.
See the MPI man page for a full list of MPI error codes.
See the Error Handling section of the MPI-3.1 standard for more information.
SEE ALSO:
• MPI_Type_create_hvector
• MPI_Type_hvector
COPYRIGHT
2003-2025, The Open MPI Community
Feb 17, 2025 MPI_TYPE_VECTOR(3)