bionic (3) MPI_Ialltoallv.openmpi.3.gz

NAME

       MPI_Alltoallv  -  Sends data from all to all processes; each process may  send a different amount of data
       and provide displacements for the input and output data.

SYNOPSIS

       int MPI_Alltoallv(const void *sendbuf, const int *sendcounts,
                         const int *sdispls, MPI_Datatype sendtype, void *recvbuf,
                         const int *recvcounts, const int *rdispls, MPI_Datatype recvtype,
                         MPI_Comm comm)

INPUT PARAMETERS

       sendbuf
              - starting address of send buffer (choice)
       sendcounts
              - integer array equal to the group size  specifying  the  number  of  elements  to  send  to  each
              processor
       sdispls
              -  integer  array  (of length group size). Entry j specifies the displacement (relative to sendbuf
              from which to take the outgoing data destined for process j

       sendtype
              - data type of send buffer elements (handle)
       recvcounts
              - integer array equal to the group size specifying the maximum number  of  elements  that  can  be
              received from each processor
       rdispls
              -  integer  array  (of length group size). Entry i specifies the displacement (relative to recvbuf
              at which to place the incoming data from process i

       recvtype
              - data type of receive buffer elements (handle)
       comm   - communicator (handle)

OUTPUT PARAMETERS

       recvbuf
              - address of receive buffer (choice)

THREAD AND INTERRUPT SAFETY

       This routine is thread-safe.  This means that this routine may be safely used by multiple threads without
       the  need  for  any  user-provided thread locks.  However, the routine is not interrupt safe.  Typically,
       this is due to the use of memory allocation routines such as malloc or other non-MPICH  runtime  routines
       that are themselves not interrupt-safe.

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 guarentee that an MPI program can continue past an error; however, MPI
       implementations will attempt to continue whenever possible.

       MPI_ERR_COMM
              - Invalid communicator.  A common error is to use a null communicator in a call (not even  allowed
              in MPI_Comm_rank ).
       MPI_ERR_COUNT
              - Invalid count argument.  Count arguments must be non-negative; a count of zero is often valid.
       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_BUFFER
              - Invalid buffer pointer.  Usually a null buffer where one is not valid.

                                                   11/12/2016                                   MPI_Alltoallv(3)