/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */

/*

 *

 *  (C) 2003 by Argonne National Laboratory.

 *      See COPYRIGHT in top-level directory.

 */

#include "mpi.h"

#include <stdio.h>

#include <stdlib.h>

#include "mpitest.h"

/*

static char MTEST_Descrip[] = "Test MPI_Exscan (simple test)";

*/

int main(int argc, char *argv[])

{

    int errs = 0;

    int rank, size;

    int sendbuf[1], recvbuf[1];

    MPI_Comm comm;

    MTest_Init(&argc, &argv);

    comm = MPI_COMM_WORLD;

    MPI_Comm_rank(comm, &rank;;

    MPI_Comm_size(comm, &size);

    sendbuf[0] = rank;

    recvbuf[0] = -2;

    MPI_Exscan(sendbuf, recvbuf, 1, MPI_INT, MPI_SUM, comm);

    /* Check the results.  rank 0 has no data.  Input is

     * 0  1  2  3  4  5  6  7  8 ...

     * Output is

     * -  0  1  3  6 10 15 21 28 36

     * (scan, not counting the contribution from the calling process)

     */

    if (rank > 0) {

        int result = (((rank) * (rank - 1)) / 2);

        /* printf("%d: %d\n", rank, result); */

        if (recvbuf[0] != result) {

            errs++;

            fprintf(stderr, "Error in recvbuf = %d on %d, expected %d\n", recvbuf[0], rank, result);

        }

    }

    else if (recvbuf[0] != -2) {

        errs++;

        fprintf(stderr, "Error in recvbuf on zero, is %d\n", recvbuf[0]);

    }

    MTest_Finalize(errs);

    MPI_Finalize();

    return 0;

}