graph_nbr.c

刚才是说明 现在是安装程序在 LINUX环境下进行编程的MPICH安装文件

/* -*- Mode: C; c-basic-offset:4 ; -*- */
/*
 *
 *  (C) 2001 by Argonne National Laboratory.
 *      See COPYRIGHT in top-level directory.
 */

#include "mpiimpl.h"
#include "topo.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
#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
#define MPI_Graph_neighbors PMPI_Graph_neighbors

#endif

#undef FUNCNAME
#define FUNCNAME MPI_Graph_neighbors

/*@
 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 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)
{
    static const char FCNAME[] = "MPI_Graph_neighbors";
    int mpi_errno = MPI_SUCCESS;
    MPID_Comm *comm_ptr = NULL;
    MPIR_Topology *graph_ptr;
    int i, is, ie;
    MPID_MPI_STATE_DECL(MPID_STATE_MPI_GRAPH_NEIGHBORS);

    MPID_MPI_FUNC_ENTER(MPID_STATE_MPI_GRAPH_NEIGHBORS);
    /* Get handles to MPI objects. */
    MPID_Comm_get_ptr( comm, comm_ptr );
#   ifdef HAVE_ERROR_CHECKING
    {
        MPID_BEGIN_ERROR_CHECKS;
        {
	    MPIR_ERRTEST_INITIALIZED(mpi_errno);
            /* Validate comm_ptr */
            MPID_Comm_valid_ptr( comm_ptr, mpi_errno );
	    /* If comm_ptr is not valid, it will be reset to null */
	    MPIR_ERRTEST_ARGNULL(neighbors,"neighbors",mpi_errno);
            if (mpi_errno) {
                MPID_MPI_FUNC_EXIT(MPID_STATE_MPI_GRAPH_NEIGHBORS);
                return MPIR_Err_return_comm( comm_ptr, FCNAME, mpi_errno );
            }
        }
        MPID_END_ERROR_CHECKS;
    }
#   endif /* HAVE_ERROR_CHECKING */

    /* ... body of routine ...  */
    graph_ptr = MPIR_Topology_get( comm_ptr );

#   ifdef HAVE_ERROR_CHECKING
    {
        MPID_BEGIN_ERROR_CHECKS;
        {
	    if (!graph_ptr || graph_ptr->kind != MPI_GRAPH) {
		mpi_errno = MPIR_Err_create_code( MPI_ERR_TOPOLOGY, 
						  "**notgraphtopo", 0 );
	    }
	    else if (rank < 0 || rank >= graph_ptr->topo.graph.nnodes) {
		mpi_errno = MPIR_Err_create_code( MPI_ERR_RANK,
					  "**rank", "**rank %d %d",
					  rank, graph_ptr->topo.graph.nnodes );
	    }
	    if (mpi_errno) {
		MPID_MPI_FUNC_EXIT(MPID_STATE_MPI_GRAPH_NEIGHBORS);
		return MPIR_Err_return_comm( comm_ptr, FCNAME, mpi_errno );
	    }
	}
        MPID_END_ERROR_CHECKS;
    }
#   endif /* HAVE_ERROR_CHECKING */

    /* 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];
    
    /* ... end of body of routine ... */
    MPID_MPI_FUNC_EXIT(MPID_STATE_MPI_GRAPH_NEIGHBORS);
    return MPI_SUCCESS;
}