MPI_Reduce_scatter(3)

NAME
     MPI_Reduce_scatter - Combines values and scatters the results

SYNOPSIS
     C:

          #include <mpi.h>

          int MPI_Reduce_scatter ( sendbuf, recvbuf, recvcounts,
          datatype, op, comm )
          void             *sendbuf;
          void             *recvbuf;
          int              *recvcounts;
          MPI_Datatype      datatype;
          MPI_Op            op;
          MPI_Comm          comm;


     C++:

          #include <mpi.h>

          void Intracomm::Reduce_scatter(
          const void*       sendbuf,
          void*             recvbuf,
          int               recvcounts[],
          const Datatype&   datatype,
          const Op&         op) const


     Fortran:

          INCLUDE "mpif.h" (or USE MPI)

          <type> SENDBUF(*), RECVBUF(*)
          INTEGER recvcounts(*), datatype, op, comm, ierror

          CALL MPI_REDUCE_SCATTER(sendbuf, recvbuf, recvcounts(*), datatype, op, comm, ierror)


STANDARDS
     This release implements the MPI 1.2 standard, as documented by the MPI
     Forum in the spring 1997 release of MPI:  A Message Passing Interface
     Standard.

     The MPI_IN_PLACE option as defined in the MPI 2.0 standard is also
     supported in this implementation.

DESCRIPTION
     The MPI_Reduce_scatter routine combines values and scatters the results.
     This routine accepts the following parameters:
     sendbuf        Specifies the starting address of the send buffer
                    (choice).  You may also pass in the argument MPI_IN_PLACE
                    for the value of sendbuf at all processes.  In this case,
                    the input data is taken from the top of the receive
                    buffer.  Note that the area occupied by the input data may
                    be either longer or shorter than that filled by the output
                    data, and that Fortran bindings for recvbuf that include
                    INTENT should mark it as INOUT, not OUT.

     recvcounts     Specifies the integer array that specifies the number of
                    elements in the result that is distributed to each
                    process.  The array must be identical on all calling
                    processes.

     datatype       Specifies the data type of elements of the input buffer
                    (handle)

     op             Specifies the operation (handle)

     comm           Specifies the communicator (handle)

     recvbuf        Returns the starting address of the receive buffer
                    (choice)

     ierror         Specifies the return code value for successful completion,
                    which is in MPI_SUCCESS.  MPI_SUCCESS is defined in the
                    mpif.h file.