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

/*

 *

 *  (C) 2001 by Argonne National Laboratory.

 *      See COPYRIGHT in top-level directory.

 */

#include "mpiimpl.h"

/* -- Begin Profiling Symbol Block for routine MPI_Graph_neighbors */

#if defined(HAVE_PRAGMA_WEAK)

#pragma weak MPI_Graph_neighbors = PMPI_Graph_neighbors

#elif defined(HAVE_PRAGMA_HP_SEC_DEF)

#pragma _HP_SECONDARY_DEF PMPI_Graph_neighbors  MPI_Graph_neighbors

#elif defined(HAVE_PRAGMA_CRI_DUP)

#pragma _CRI duplicate MPI_Graph_neighbors as PMPI_Graph_neighbors

#elif defined(HAVE_WEAK_ATTRIBUTE)

int MPI_Graph_neighbors(MPI_Comm comm, int rank, int maxneighbors, int neighbors[])

    __attribute__ ((weak, alias("PMPI_Graph_neighbors")));

#endif

/* -- End Profiling Symbol Block */

/* Define MPICH_MPI_FROM_PMPI if weak symbols are not supported to build

   the MPI routines */

#ifndef MPICH_MPI_FROM_PMPI

#undef MPI_Graph_neighbors

#define MPI_Graph_neighbors PMPI_Graph_neighbors

/* any non-MPI functions go here, especially non-static ones */

#undef FUNCNAME

#define FUNCNAME MPIR_Graph_neighbors_impl

#undef FCNAME

#define FCNAME MPL_QUOTE(FUNCNAME)

int MPIR_Graph_neighbors_impl(MPIR_Comm * comm_ptr, int rank, int maxneighbors, int neighbors[])

{

    int mpi_errno = MPI_SUCCESS;

    MPIR_Topology *graph_ptr;

    int i, is, ie;

    graph_ptr = MPIR_Topology_get(comm_ptr);

    MPIR_ERR_CHKANDJUMP((!graph_ptr ||

                         graph_ptr->kind != MPI_GRAPH), mpi_errno, MPI_ERR_TOPOLOGY,

                        "**notgraphtopo");

    MPIR_ERR_CHKANDJUMP2((rank < 0 ||

                          rank >= graph_ptr->topo.graph.nnodes), mpi_errno, MPI_ERR_RANK, "**rank",

                         "**rank %d %d", rank, graph_ptr->topo.graph.nnodes);

    /* Get location in edges array of the neighbors of the specified rank */

    if (rank == 0)

        is = 0;

    else

        is = graph_ptr->topo.graph.index[rank - 1];

    ie = graph_ptr->topo.graph.index[rank];

    /* Get neighbors */

    for (i = is; i < ie; i++)

        *neighbors++ = graph_ptr->topo.graph.edges[i];

  fn_exit:

    return mpi_errno;

  fn_fail:

    goto fn_exit;

}

#endif

#undef FUNCNAME

#define FUNCNAME MPI_Graph_neighbors

#undef FCNAME

#define FCNAME MPL_QUOTE(FUNCNAME)

/*@

 MPI_Graph_neighbors - Returns the neighbors of a node associated

                       with a graph topology

Input Parameters:

+ comm - communicator with graph topology (handle)

. rank - rank of process in group of comm (integer)

- maxneighbors - size of array neighbors (integer)

Output Parameters:

. neighbors - ranks of processes that are neighbors to specified process

 (array of integer)

.N SignalSafe

.N Fortran

.N Errors

.N MPI_SUCCESS

.N MPI_ERR_TOPOLOGY

.N MPI_ERR_COMM

.N MPI_ERR_ARG

.N MPI_ERR_RANK

@*/

int MPI_Graph_neighbors(MPI_Comm comm, int rank, int maxneighbors, int neighbors[])

{

    int mpi_errno = MPI_SUCCESS;

    MPIR_Comm *comm_ptr = NULL;

    MPIR_FUNC_TERSE_STATE_DECL(MPID_STATE_MPI_GRAPH_NEIGHBORS);

    MPIR_ERRTEST_INITIALIZED_ORDIE();

    MPIR_FUNC_TERSE_ENTER(MPID_STATE_MPI_GRAPH_NEIGHBORS);

    /* Validate parameters, especially handles needing to be converted */

#ifdef HAVE_ERROR_CHECKING

    {

        MPID_BEGIN_ERROR_CHECKS;

        {

            MPIR_ERRTEST_COMM(comm, mpi_errno);

        }

        MPID_END_ERROR_CHECKS;

    }

#endif

    /* Convert MPI object handles to object pointers */

    MPIR_Comm_get_ptr(comm, comm_ptr);

    /* Validate parameters and objects (post conversion) */

#ifdef HAVE_ERROR_CHECKING

    {

        MPID_BEGIN_ERROR_CHECKS;

        {

            /* Validate comm_ptr */

            MPIR_Comm_valid_ptr(comm_ptr, mpi_errno, FALSE);

            if (mpi_errno)

                goto fn_fail;

            /* If comm_ptr is not valid, it will be reset to null */

            MPIR_ERRTEST_ARGNULL(neighbors, "neighbors", mpi_errno);

        }

        MPID_END_ERROR_CHECKS;

    }

#endif /* HAVE_ERROR_CHECKING */

    /* ... body of routine ...  */

    mpi_errno = MPIR_Graph_neighbors_impl(comm_ptr, rank, maxneighbors, neighbors);

    if (mpi_errno)

        MPIR_ERR_POP(mpi_errno);

    /* ... end of body of routine ... */

  fn_exit:

    MPIR_FUNC_TERSE_EXIT(MPID_STATE_MPI_GRAPH_NEIGHBORS);

    return mpi_errno;

  fn_fail:

    /* --BEGIN ERROR HANDLING-- */

#ifdef HAVE_ERROR_CHECKING

    {

        mpi_errno =

            MPIR_Err_create_code(mpi_errno, MPIR_ERR_RECOVERABLE, FCNAME, __LINE__, MPI_ERR_OTHER,

                                 "**mpi_graph_neighbors", "**mpi_graph_neighbors %C %d %d %p", comm,

                                 rank, maxneighbors, neighbors);

    }

#endif

    mpi_errno = MPIR_Err_return_comm(comm_ptr, FCNAME, mpi_errno);

    goto fn_exit;

    /* --END ERROR HANDLING-- */

}