Ubuntu Manpage: MPI_Get_accumulate - Perform an atomic, one-sided read-and-accumulate operation

name
synopsis
input parameters
output parameters
notes
notes for fortran
errors
see also

noble (3) MPI_Rget_accumulate.openmpi.3.gz

Provided by: mpich-doc_4.2.0-5build3_all

NAME

       MPI_Get_accumulate -  Perform an atomic, one-sided read-and-accumulate operation

SYNOPSIS

       int MPI_Get_accumulate(const void *origin_addr, int origin_count,
       MPI_Datatype origin_datatype, void *result_addr,
       int result_count, MPI_Datatype result_datatype,
       int target_rank, MPI_Aint target_disp, int target_count,
       MPI_Datatype target_datatype, MPI_Op op, MPI_Win win)

       int MPI_Get_accumulate_c(const void *origin_addr, MPI_Count origin_count,
       MPI_Datatype origin_datatype, void *result_addr,
       MPI_Count result_count, MPI_Datatype result_datatype,
       int target_rank, MPI_Aint target_disp,
       MPI_Count target_count, MPI_Datatype target_datatype,
       MPI_Op op, MPI_Win win)

INPUT PARAMETERS

       origin_addr
              - initial address of buffer (choice)
       origin_count
              - number of entries in origin buffer (non-negative integer)
       origin_datatype
              - datatype of each entry in origin buffer (handle)
       result_count
              - number of entries in result buffer (non-negative integer)
       result_datatype
              - datatype of each entry in result buffer (handle)
       target_rank
              - rank of target (non-negative integer)
       target_disp
              - displacement from start of window to beginning of target buffer (non-negative integer)
       target_count
              - number of entries in target buffer (non-negative integer)
       target_datatype
              - datatype of each entry in target buffer (handle)
       op     - reduce operation (handle)
       win    - window object (handle)

OUTPUT PARAMETERS

       result_addr
              - initial address of result buffer (choice)

NOTES

This operations is atomic with respect to other "accumulate" operations.

The get and accumulate steps are executed atomically for each basic element in the datatype (see MPI 3.0
Section 11.7 for details). The predefined operation MPI_REPLACE provides fetch-and-set behavior.

The origin and result buffers (origin_addr and result_addr) must be disjoint. Each datatype argument
must be a predefined datatype or a derived datatype where all basic components are of the same predefined
datatype. All datatype arguments must be constructed from the same predefined datatype. The operation op
applies to elements of that predefined type. target_datatype must not specify overlapping entries, and
the target buffer must fit in the target window or in attached memory in a dynamic window.

Any of the predefined operations for MPI_Reduce , as well as MPI_NO_OP or MPI_REPLACE can be specified as
op. User-defined functions cannot be used. A new predefined operation, MPI_NO_OP , is defined. It
corresponds to the associative function f (a, b) = a; i.e., the current value in the target memory is
returned in the result buffer at the origin and no operation is performed on the target buffer.
MPI_NO_OP can be used only in MPI_Get_accumulate , MPI_Rget_accumulate , and MPI_Fetch_and_op .
MPI_NO_OP cannot be used in MPI_Accumulate , MPI_Raccumulate , or collective reduction operations, such
as MPI_Reduce and others.

NOTES FOR FORTRAN

       All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have an additional argument ierr at the
       end of the argument list.  ierr is an integer and has the same meaning as the return value of the routine
       in C.  In Fortran, MPI routines are subroutines, and are invoked with the call statement.

       All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in Fortran.

ERRORS

       All MPI routines (except MPI_Wtime and MPI_Wtick ) return an error value; C routines as the value of  the
       function  and Fortran routines in the last argument.  Before the value is returned, the current MPI error
       handler is called.  By default, this error handler aborts the MPI job.  The error handler may be  changed
       with    MPI_Comm_set_errhandler   (for   communicators),   MPI_File_set_errhandler   (for   files),   and
       MPI_Win_set_errhandler (for RMA windows).  The MPI-1 routine MPI_Errhandler_set may be used but  its  use
       is  deprecated.   The  predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be
       returned.  Note that MPI does not guarantee that an MPI program can continue past an error; however,  MPI
       implementations will attempt to continue whenever possible.

       MPI_SUCCESS
              - No error; MPI routine completed successfully.
       MPI_ERR_BUFFER
              - Invalid buffer pointer.  Usually a null buffer where one is not valid.
       MPI_ERR_COUNT
              - Invalid count argument.  Count arguments must be non-negative; a count of zero is often valid.
       MPI_ERR_DISP
              -
       MPI_ERR_RANK
              - Invalid source or destination rank.  Ranks must be between zero and the size of the communicator
              minus one; ranks in a receive  (  MPI_Recv  ,  MPI_Irecv  ,  MPI_Sendrecv  ,  etc.)  may  also  be
              MPI_ANY_SOURCE .

       MPI_ERR_TYPE
              -  Invalid  datatype  argument.  Additionally, this error can occur if an uncommitted MPI_Datatype
              (see MPI_Type_commit ) is used in a communication call.
       MPI_ERR_WIN
              - Invalid MPI window object
       MPI_ERR_OTHER
              - Other error; use MPI_Error_string to get more information about this error code.