/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil -*- */
/*
 * Copyright (c) 2004-2007 The Trustees of Indiana University and Indiana
 *                         University Research and Technology
 *                         Corporation.  All rights reserved.
 * Copyright (c) 2004-2012 The University of Tennessee and The University
 *                         of Tennessee Research Foundation.  All rights
 *                         reserved.
 * Copyright (c) 2004-2008 High Performance Computing Center Stuttgart, 
 *                         University of Stuttgart.  All rights reserved.
 * Copyright (c) 2004-2005 The Regents of the University of California.
 *                         All rights reserved.
 * Copyright (c) 2007-2012 Cisco Systems, Inc.  All rights reserved.
 * Copyright (c) 2012-2013 Los Alamos National Security, LLC.  All rights
 *                         reserved. 
 * $COPYRIGHT$
 * 
 * Additional copyrights may follow
 * 
 * $HEADER$
 */
#include "ompi_config.h"
#include <stdio.h>

#include "ompi/mpi/c/bindings.h"
#include "ompi/runtime/params.h"
#include "ompi/communicator/communicator.h"
#include "ompi/errhandler/errhandler.h"
#include "ompi/mca/topo/base/base.h"
#include "ompi/memchecker.h"

#if OPAL_HAVE_WEAK_SYMBOLS && OMPI_PROFILING_DEFINES
#pragma weak MPI_Graph_create = PMPI_Graph_create
#endif

#if OMPI_PROFILING_DEFINES
#include "ompi/mpi/c/profile/defines.h"
#endif

static const char FUNC_NAME[] = "MPI_Graph_create";


int MPI_Graph_create(MPI_Comm old_comm, int nnodes, const int indx[],
                     const int edges[], int reorder, MPI_Comm *comm_graph)
{
    mca_topo_base_module_t* topo;
    int err;

    MEMCHECKER(
        memchecker_comm(old_comm);
    );

    /* check the arguments */
    if (MPI_PARAM_CHECK) {
        OMPI_ERR_INIT_FINALIZE(FUNC_NAME);
        if (ompi_comm_invalid(old_comm)) {
            return OMPI_ERRHANDLER_INVOKE (MPI_COMM_WORLD, MPI_ERR_COMM,
                                           FUNC_NAME);
        } else if (OMPI_COMM_IS_INTER(old_comm)) {
            return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD, MPI_ERR_COMM, 
                                          FUNC_NAME);
        }
        if (nnodes < 0) {
            return OMPI_ERRHANDLER_INVOKE (old_comm, MPI_ERR_ARG,
                                           FUNC_NAME);
        } else if (nnodes >= 1 && ((NULL == indx) || (NULL == edges))) {
            return OMPI_ERRHANDLER_INVOKE (old_comm, MPI_ERR_ARG,
                                           FUNC_NAME);
        }

        if (nnodes > ompi_comm_size(old_comm)) {
            return OMPI_ERRHANDLER_INVOKE (old_comm, MPI_ERR_ARG,
                                           FUNC_NAME);
        }
    }

    /* MPI-2.1 7.5.3 states that if nnodes == 0, all processes should
       get MPI_COMM_NULL */
    if (0 == nnodes) {
        *comm_graph = MPI_COMM_NULL;
        return MPI_SUCCESS;
    }
    if( nnodes > old_comm->c_local_group->grp_proc_count ) {
        return OMPI_ERRHANDLER_INVOKE (old_comm, MPI_ERR_ARG,
                                       FUNC_NAME);
    }

    OPAL_CR_ENTER_LIBRARY();
    /* 
     * everything seems to be alright with the communicator, we can go 
     * ahead and select a topology module for this purpose and create 
     * the new graph communicator
     */
    if (OMPI_SUCCESS != (err = mca_topo_base_comm_select(old_comm,
                                                         NULL,
                                                         &topo,
                                                         OMPI_COMM_GRAPH))) {
        return err;
    }

    /* Now let that topology module rearrange procs/ranks if it wants to */    
    /* XXX -- CONST -- do not cast away const -- update mca/topo */
    err = topo->topo.graph.graph_create(topo, old_comm,
                                        nnodes, (int *) indx, (int *) edges,
                                        (0 == reorder) ? false : true, comm_graph);
    OPAL_CR_EXIT_LIBRARY();

    if (MPI_SUCCESS != err) {
        OBJ_RELEASE(topo);
        return OMPI_ERRHANDLER_INVOKE(old_comm, err, FUNC_NAME);
    }
    
    /* All done */
    return MPI_SUCCESS;
}