NAME

       MPI_Neighbor_alltoallv  -  The vector variant of MPI_Neighbor_alltoall allows sending/receiving different
       numbers of elements to and from each neighbor.

SYNOPSIS

       int MPI_Neighbor_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 the send buffer (choice)
       sendcounts
              - non-negative integer array (of length outdegree) specifying the number of elements  to  send  to
              each neighbor
       sdispls
              -  integer  array (of length outdegree).  Entry j specifies the displacement (relative to sendbuf)
              from which to send the outgoing data to neighbor j
       sendtype
              - data type of send buffer elements (handle)
       recvcounts
              - non-negative integer array (of length indegree) specifying  the  number  of  elements  that  are
              received from each neighbor
       rdispls
              - integer array (of length indegree).  Entry i specifies the displacement (relative to recvbuf) at
              which to place the incoming data from neighbor i.
       recvtype
              - data type of receive buffer elements (handle)
       comm   - communicator with topology structure (handle)

OUTPUT PARAMETERS

       recvbuf
              - starting address of the 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.

                                                   11/12/2016                          MPI_Neighbor_alltoallv(3)