NAME

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

SYNOPSIS

       int MPI_Ialltoallv(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, MPI_Request * request)

INPUT PARAMETERS

       sendbuf
              - starting address of the send buffer (choice)
       sendcounts
              - non-negative integer array (of length 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
              - non-negative integer array (of length group size) specifying the 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
              - starting address of the receive buffer (choice)
       request
              - communication request (handle)

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.

                                                   11/12/2019                                  MPI_Ialltoallv(3)