/* -*- 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 "mpitest.h"

#include <stdlib.h>

#include <stdio.h>

/* This example sends a vector and receives individual elements, but the

   root process does not receive any data */

int main(int argc, char **argv)

{

    MPI_Datatype vec;

    double *vecin, *vecout, ivalue;

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

    int rank, size;

    MPI_Aint vextent;

    MTest_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;;

    MPI_Type_extent(vec, &vextent);

    if (vextent != ((n - 1) * (MPI_Aint) stride + 1) * sizeof(double)) {

        err++;

        printf("Vector extent is %ld, should be %ld\n",

               (long) vextent, (long) (((n - 1) * stride + 1) * sizeof(double)));

    }

    /* Note that the exted of type vector is from the first to the

     * last element, not n*stride.

     * E.g., with n=1, the extent is a single double */

    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;

        if (rank == root) {

            MPI_Scatter(vecin, 1, vec, MPI_IN_PLACE, -1, MPI_DATATYPE_NULL, root, MPI_COMM_WORLD);

        }

        else {

            MPI_Scatter(NULL, -1, MPI_DATATYPE_NULL, 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("[%d] Expected %f but found %f for vecout[%d]\n",

                           rank, ivalue, vecout[i], i);

                    err++;

                }

                ivalue += stride;

            }

        }

    }

    free(vecin);

    free(vecout);

    MTest_Finalize(err);

    MPI_Type_free(&vec;;

    MPI_Finalize();

    return 0;

}