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

/*

 *

 *  (C) 2008 by Argonne National Laboratory.

 *      See COPYRIGHT in top-level directory.

 */

#include "mpi.h"

#include <stdio.h>

#include "mpitest.h"

/*

    Check that the MPI implementation properly handles zero-dimensional

    Cartesian communicators - the original standard implies that these

    should be consistent with higher dimensional topologies and thus

    these should work with any MPI implementation.  MPI 2.1 made this

    requirement explicit.

*/

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

{

    int errs = 0;

    int size, rank, ndims;

    MPI_Comm comm, newcomm;

    MTest_Init(&argc, &argv);

    /* Create a new cartesian communicator in a subset of the processes */

    MPI_Comm_size(MPI_COMM_WORLD, &size);

    MPI_Comm_rank(MPI_COMM_WORLD, &rank;;

    if (size < 2) {

        fprintf(stderr, "This test needs at least 2 processes\n");

        MPI_Abort(MPI_COMM_WORLD, 1);

    }

    MPI_Cart_create(MPI_COMM_WORLD, 0, NULL, NULL, 0, &comm);

    if (comm != MPI_COMM_NULL) {

        int csize;

        MPI_Comm_size(comm, &csize);

        if (csize != 1) {

            errs++;

            fprintf(stderr, "Sizes is wrong in cart communicator.  Is %d, should be 1\n", csize);

        }

        /* This function is not meaningful, but should not fail */

        MPI_Dims_create(1, 0, NULL);

        ndims = -1;

        MPI_Cartdim_get(comm, &ndims);

        if (ndims != 0) {

            errs++;

            fprintf(stderr, "MPI_Cartdim_get: ndims is %d, should be 0\n", ndims);

        }

        /* this function should not fail */

        MPI_Cart_get(comm, 0, NULL, NULL, NULL);

        MPI_Cart_rank(comm, NULL, &rank;;

        if (rank != 0) {

            errs++;

            fprintf(stderr, "MPI_Cart_rank: rank is %d, should be 0\n", rank);

        }

        /* this function should not fail */

        MPI_Cart_coords(comm, 0, 0, NULL);

        MPI_Cart_sub(comm, NULL, &newcomm);

        ndims = -1;

        MPI_Cartdim_get(newcomm, &ndims);

        if (ndims != 0) {

            errs++;

            fprintf(stderr, "MPI_Cart_sub did not return zero-dimensional communicator\n");

        }

        MPI_Barrier(comm);

        MPI_Comm_free(&comm);

        MPI_Comm_free(&newcomm);

    } else if (rank == 0) {

        errs++;

        fprintf(stderr, "Communicator returned is null!");

    }

    MTest_Finalize(errs);

    return MTestReturnValue(errs);

}