/* -*- 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_Allreduce with apparent non-commutative operators";

*/

/* While the operator is in fact commutative, this forces the MPI code to

   run the code that is used for non-commutative operators, and for

   various message lengths.  Other tests check truly non-commutative

   operators */

void mysum(void *cinPtr, void *coutPtr, int *count, MPI_Datatype * dtype);

void mysum(void *cinPtr, void *coutPtr, int *count, MPI_Datatype * dtype)

{

    const int *cin = (const int *) cinPtr;

    int *cout = (int *) coutPtr;

    int i, n = *count;

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

        cout[i] += cin[i];

}

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

{

    int errs = 0;

    int rank, size;

    int minsize = 2, count;

    MPI_Comm comm;

    MPI_Op op;

    int *buf, i;

    MTest_Init(&argc, &argv);

    MPI_Op_create(mysum, 0, &op);

    while (MTestGetIntracommGeneral(&comm, minsize, 1)) {

        if (comm == MPI_COMM_NULL)

            continue;

        MPI_Comm_size(comm, &size);

        MPI_Comm_rank(comm, &rank;;

        for (count = 1; count < 65000; count = count * 2) {

            /* Contiguous data */

            buf = (int *) malloc(count * sizeof(int));

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

                buf[i] = rank + i;

            MPI_Allreduce(MPI_IN_PLACE, buf, count, MPI_INT, op, comm);

            /* Check the results */

            for (i = 0; i < count; i++) {

                int result = i * size + (size * (size - 1)) / 2;

                if (buf[i] != result) {

                    errs++;

                    if (errs < 10) {

                        fprintf(stderr, "buf[%d] = %d expected %d\n", i, buf[i], result);

                    }

                }

            }

            free(buf);

        }

        MTestFreeComm(&comm);

    }

    MPI_Op_free(&op);

    MTest_Finalize(errs);

    return MTestReturnValue(errs);

}