MPI_Alltoallv(3)                      MPI                     MPI_Alltoallv(3)



NAME
       MPI_Alltoallv -  Sends data from all to all processes, with a displace-
       ment

SYNOPSIS
       #include "mpi.h"
       int MPI_Alltoallv (
               void *sendbuf,
               int *sendcnts,
               int *sdispls,
               MPI_Datatype sendtype,
               void *recvbuf,
               int *recvcnts,
               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 outgo-
              ing 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 incom-
              ing data from process i

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


OUTPUT PARAMETER
       recvbuf
              - address of receive buffer (choice)


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_Errhandler_set ; the prede-
       fined 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.

       MPI_ERR_COMM
              - Invalid communicator.  A common error is to use a null  commu-
              nicator 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.  May be an uncommitted MPI_Datatype
              (see MPI_Type_commit ).
       MPI_ERR_BUFFER
              -  Invalid  buffer  pointer.  Usually a null buffer where one is
              not valid.

LOCATION
       alltoallv.c



                                  11/14/2001                  MPI_Alltoallv(3)