/* -*- 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 "mpitest.h"

int main(int argc, char *argv[])
{
    int errs = 0;
    int size, dims[2], periods[2], remain[2];
    int result, rank;
    MPI_Comm comm, newcomm;

    MTest_Init(&argc, &argv);

    /* First, create a 1-dim cartesian communicator */
    periods[0] = 0;
    MPI_Comm_size(MPI_COMM_WORLD, &size);
    dims[0] = size;
    MPI_Cart_create(MPI_COMM_WORLD, 1, dims, periods, 0, &comm);

    /* Now, extract a communicator with no dimensions */
    remain[0] = 0;
    MPI_Cart_sub(comm, remain, &newcomm);

    MPI_Comm_rank(comm, &rank);

    if (rank == 0) {
        /* This should be congruent to MPI_COMM_SELF */
        MPI_Comm_compare(MPI_COMM_SELF, newcomm, &result);
        if (result != MPI_CONGRUENT) {
            errs++;
            printf("cart sub to size 0 did not give self\n");
        }
        MPI_Comm_free(&newcomm);
    } else if (newcomm != MPI_COMM_NULL) {
        errs++;
        printf("cart sub to size 0 did not give null\n");
    }

    /* Free the new communicator so that storage leak tests will
     * be happy */
    MPI_Comm_free(&comm);

    MTest_Finalize(errs);
    return MTestReturnValue(errs);
}