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

/*

 *  (C) 2015 by Argonne National Laboratory.

 *      See COPYRIGHT in top-level directory.

 */

#include "mpi.h"

#include "mpitestconf.h"

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#include <assert.h>

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

{

    int size, rank;

    MPI_Group world_group;

    MPI_Comm group_comm, idup_comm;

    MPI_Request req;

    MPI_Init(&argc, &argv);

    MPI_Comm_size(MPI_COMM_WORLD, &size);

    MPI_Comm_rank(MPI_COMM_WORLD, &rank;;

    if (size % 2) {

        fprintf(stderr, "this program requires even number of processes\n");

        MPI_Abort(MPI_COMM_WORLD, 1);

    }

    /* Create some groups */

    MPI_Comm_group(MPI_COMM_WORLD, &world_group);

    if (rank % 2 == 0) {

        MPI_Comm_create_group(MPI_COMM_WORLD, world_group, 0, &group_comm);

        MPI_Comm_idup(MPI_COMM_WORLD, &idup_comm, &req;;

    }

    else {

        MPI_Comm_idup(MPI_COMM_WORLD, &idup_comm, &req;;

        MPI_Comm_create_group(MPI_COMM_WORLD, world_group, 0, &group_comm);

    }

    MPI_Wait(&req, MPI_STATUSES_IGNORE);

    /*Test new comm with a barrier */

    MPI_Barrier(idup_comm);

    MPI_Barrier(group_comm);

    MPI_Group_free(&world_group);

    MPI_Comm_free(&idup_comm);

    MPI_Comm_free(&group_comm);

    if (rank == 0)

        printf(" No errors\n");

    MPI_Finalize();

    return 0;

}