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

/*

 *  (C) 2001 by Argonne National Laboratory.

 *      See COPYRIGHT in top-level directory.

 */

/*

 * Test of reduce scatter.

 *

 * Each processor contributes its rank + the index to the reduction,

 * then receives the ith sum

 *

 * Can be called with any number of processors.

 */

#include "mpi.h"

#include <stdio.h>

#include <stdlib.h>

#include "mpicolltest.h"

int main(int argc, char **argv)

{

    int err = 0, toterr;

    int *sendbuf, recvbuf, *recvcounts;

    int size, rank, i, sumval;

    MPI_Comm comm;

    MPI_Init(&argc, &argv);

    comm = MPI_COMM_WORLD;

    MPI_Comm_size(comm, &size);

    MPI_Comm_rank(comm, &rank;;

    sendbuf = (int *) malloc(size * sizeof(int));

    for (i = 0; i < size; i++)

        sendbuf[i] = rank + i;

    recvcounts = (int *) malloc(size * sizeof(int));

    for (i = 0; i < size; i++)

        recvcounts[i] = 1;

    MTest_Reduce_scatter(sendbuf, &recvbuf, recvcounts, MPI_INT, MPI_SUM, comm);

    sumval = size * rank + ((size - 1) * size) / 2;

/* recvbuf should be size * (rank + i) */

    if (recvbuf != sumval) {

        err++;

        fprintf(stdout, "Did not get expected value for reduce scatter\n");

        fprintf(stdout, "[%d] Got %d expected %d\n", rank, recvbuf, sumval);

    }

    MPI_Allreduce(&err, &toterr, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD);

    if (rank == 0 && toterr == 0) {

        printf(" No Errors\n");

    }

    free(sendbuf);

    free(recvcounts);

    MPI_Finalize();

    return toterr;

}