plucky (3) MPI_Rget_accumulate.openmpi.3.gz

Provided by: openmpi-doc_5.0.7-1_all bug

SYNTAX

   C Syntax
          #include <mpi.h>

          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_Rget_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,
              MPI_Request *request)

   Fortran Syntax
          USE MPI
          ! or the older form: INCLUDE 'mpif.h'

          MPI_GET_ACCUMULATE(ORIGIN_ADDR, ORIGIN_COUNT, ORIGIN_DATATYPE, RESULT_ADDR,
                  RESULT_COUNT, RESULT_DATATYPE, TARGET_RANK, TARGET_DISP, TARGET_COUNT,
                  TARGET_DATATYPE, OP, WIN, IERROR)
              <type> ORIGIN_ADDR, RESULT_ADDR(*)
              INTEGER(KIND=MPI_ADDRESS_KIND) TARGET_DISP
              INTEGER ORIGIN_COUNT, ORIGIN_DATATYPE, TARGET_COUNT, TARGET_DATATYPE,
                  TARGET_RANK, TARGET_COUNT, TARGET_DATATYPE, OP, WIN, IERROR

          MPI_RGET_ACCUMULATE(ORIGIN_ADDR, ORIGIN_COUNT, ORIGIN_DATATYPE, RESULT_ADDR,
                  RESULT_COUNT, RESULT_DATATYPE, TARGET_RANK, TARGET_DISP, TARGET_COUNT,
                  TARGET_DATATYPE, OP, WIN, REQUEST, IERROR)
              <type> ORIGIN_ADDR, RESULT_ADDR(*)
              INTEGER(KIND=MPI_ADDRESS_KIND) TARGET_DISP
              INTEGER ORIGIN_COUNT, ORIGIN_DATATYPE, TARGET_COUNT, TARGET_DATATYPE,
                  TARGET_RANK, TARGET_COUNT, TARGET_DATATYPE, OP, WIN, REQUEST, IERROR

   Fortran 2008 Syntax
          USE mpi_f08

          MPI_Get_accumulate(origin_addr, origin_count, origin_datatype, result_addr,
                  result_count, result_datatype, target_rank, target_disp,
                  target_count, target_datatype, op, win, ierror)
              TYPE(*), DIMENSION(..), INTENT(IN) :: origin_addr
              TYPE(*), DIMENSION(..) :: result_addr
              INTEGER, INTENT(IN) :: origin_count, result_count, target_rank, target_count
              TYPE(MPI_Datatype), INTENT(IN) :: origin_datatype, target_datatype, result_datatype
              INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(IN) :: target_dist
              TYPE(MPI_Op), INTENT(IN) :: op
              TYPE(MPI_Win), INTENT(IN) :: win
              INTEGER, OPTIONAL, INTENT(OUT) :: ierror

          MPI_Rget_accumulate(origin_addr, origin_count, origin_datatype,
                  result_addr, result_count, result_datatype, target_rank,
                  target_disp, target_count, target_datatype, op, win, request,
                  ierror)
              TYPE(*), DIMENSION(..), INTENT(IN) :: origin_addr
              TYPE(*), DIMENSION(..) :: result_addr
              INTEGER, INTENT(IN) :: origin_count, result_count, target_rank, target_count
              TYPE(MPI_Datatype), INTENT(IN) :: origin_datatype, target_datatype, result_datatype
              INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(IN) :: target_dist
              TYPE(MPI_Op), INTENT(IN) :: op
              TYPE(MPI_Win), INTENT(IN) :: win
              TYPE(MPI_Request), INTENT(OUT) :: request
              INTEGER, OPTIONAL, INTENT(OUT) :: ierror

INPUT PARAMETERS

origin_addr : Initial address of buffer (choice).

       • origin_count : Number of entries in buffer (nonnegative integer).

       • origin_datatype : Data type of each buffer entry (handle).

       • result_addr : Initial address of result buffer (choice).

       •

         result_count (Number of entries in result buffer (nonnegative)
                integer).

       • result_datatype : Data type of each result buffer entry (handle).

       • target_rank : Rank of target (nonnegative integer).

       •

         target_disp (Displacement from start of window to beginning of)
                target buffer (nonnegative integer).

       •

         target_count (Number of entries in target buffer (nonnegative)
                integer).

       • target_datatype : Data type of each entry in target buffer (handle).

       • op : Reduce operation (handle).

       • win : Window object (handle).

OUTPUT PARAMETER

MPI_Rget_accumulate: RMA request

       • ierror : Fortran only: Error status (integer).

DESCRIPTION

       MPI_Get_accumulate is a function used for one-sided MPI communication  that  adds  the  contents  of  the
       origin  buffer  (as defined by origin_addr, origin_count, and origin_datatype) to the buffer specified by
       the arguments target_count and target_datatype, at offset target_disp, in the target window specified  by
       target_rank  and win, using the operation op. MPI_Get_accumulate returns in the result buffer result_addr
       the contents of the target buffer before the accumulation.

       Any of the predefined operations for  MPI_Reduce,  as  well  as  MPI_NO_OP,  can  be  used.  User-defined
       functions  cannot  be  used. For example, if op is MPI_SUM, each element of the origin buffer is added to
       the corresponding element in the target, replacing the former value in the target.

       Each datatype argument must be a predefined data type or a derived data type, where all basic  components
       are  of  the  same  predefined  data  type.   Both  datatype  arguments must be constructed from the same
       predefined data type. The operation op applies to elements of that predefined type.  The  target_datatype
       argument must not specify overlapping entries, and the target buffer must fit in the target window.

       A  new  predefined operation, MPI_REPLACE, is defined. It corresponds to the associative function f(a, b)
       =b; that is, the current value in the target memory is replaced by the value supplied by the origin.

       A new predefined operation, MPI_NO_OP, is defined. It corresponds to the assiciative function f(a,  b)  =
       a;  that  is 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_Rget_accumulate is similar to MPI_Get_accumulate, except that it allocates  a  communication  request
       object  and associates it with the request handle (the argument request) that can be used to wait or test
       for completion. The completion of an MPI_Rget_accumulate operation indicates that the data  is  available
       in the result buffer and the origin buffer is free to be updated. It does not indicate that the operation
       has been completed at the target window.

NOTES

       The generic functionality of MPI_Get_accumulate might limit the  performance  of  fetch-and-increment  or
       fetch-and-add  calls that might be supported by special hardware operations. MPI_Fetch_and_op thus allows
       for a fast implementation of a commonly used subset of the functionality of MPI_Get_accumulate.

       MPI_Get is a special case of MPI_Get_accumulate,  with  the  operation  MPI_NO_OP.  Note,  however,  that
       MPI_Get and MPI_Get_accumulate have different constraints on concurrent updates.

       It  is  the  user’s  responsibility  to  guarantee  that, when using the accumulate functions, the target
       displacement argument is such that accesses to the window are properly aligned according to the data type
       arguments in the call to the MPI_Get_accumulate function.

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_errhandlerMPI_File_create_errhandler then MPI_File_set_errhandlerMPI_Session_create_errhandler then MPI_Session_set_errhandler or at MPI_Session_initMPI_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_Put MPI_Reduce

       2003-2025, The Open MPI Community

                                                  Feb 17, 2025                            MPI_RGET_ACCUMULATE(3)