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

/*

 *  (C) 2001 by Argonne National Laboratory.

 *      See COPYRIGHT in top-level directory.

 */

#include "mpi.h"

#include <stdlib.h>

#include <stdio.h>

/* This example sends a vector and receives individual elements */

int main(int argc, char **argv)

{

    MPI_Datatype vec;

    double *vecin, *vecout, ivalue;

    int root, i, n, stride, err = 0;

    int rank, size;

    MPI_Init(&argc, &argv);

    MPI_Comm_size(MPI_COMM_WORLD, &size);

    MPI_Comm_rank(MPI_COMM_WORLD, &rank;;

    n = 12;

    stride = 10;

    vecin = (double *) malloc(n * stride * size * sizeof(double));

    vecout = (double *) malloc(n * sizeof(double));

    MPI_Type_vector(n, 1, stride, MPI_DOUBLE, &vec;;

    MPI_Type_commit(&vec;;

    for (i = 0; i < n * stride * size; i++)

        vecin[i] = (double) i;

    for (root = 0; root < size; root++) {

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

            vecout[i] = -1.0;

        MPI_Scatter(vecin, 1, vec, vecout, n, MPI_DOUBLE, root, MPI_COMM_WORLD);

        ivalue = rank * ((n - 1) * stride + 1);

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

            if (vecout[i] != ivalue) {

                printf("Expected %f but found %f\n", ivalue, vecout[i]);

                err++;

            }

            ivalue += stride;

        }

    }

    i = err;

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

    if (rank == 0) {

        if (err > 0)

            printf("Found %d errors!\n", err);

        else

            printf(" No Errors\n");

    }

    free(vecin);

    free(vecout);

    MPI_Type_free(&vec;;

    MPI_Finalize();

    return 0;

}