topo_base_cart_coords.c

来自「MPI stands for the Message Passing Inter」· C语言 代码 · 共 69 行

/*
 * Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
 *                         University Research and Technology
 *                         Corporation.  All rights reserved.
 * Copyright (c) 2004-2005 The University of Tennessee and The University
 *                         of Tennessee Research Foundation.  All rights
 *                         reserved.
 * Copyright (c) 2004-2005 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.
 * $COPYRIGHT$
 * 
 * Additional copyrights may follow
 * 
 * $HEADER$
 */

#include "ompi_config.h"
#include "ompi/mca/topo/base/base.h"
#include "ompi/communicator/communicator.h"
#include "ompi/mca/topo/topo.h"

/*
 * function - determines process coords in cartesian topology given
 *            rank in group
 *
 * @param comm - communicator with cartesian structure (handle)
 * @param rank - rank of a process within group of 'comm' (integer)
 * @param maxdims - length of vector 'coords' in the calling program (integer)
 * @param coords - integer array (of size 'ndims') containing the cartesian
 *                   coordinates of specified process (integer)
 *
 * @retval MPI_SUCCESS
 * @retval MPI_ERR_COMM
 * @retval MPI_ERR_TOPOLOGY
 * @retval MPI_ERR_RANK
 * @retval MPI_ERR_DIMS
 * @retval MPI_ERR_ARG
 */                   

int mca_topo_base_cart_coords (MPI_Comm comm,
                           int rank,
                           int maxdims,
                           int *coords){
    int dim;
    int remprocs;
    int i;
    int *d;

    /*
     * loop computing the co-ordinates
     */ 
    d = comm->c_topo_comm->mtc_dims_or_index;
    remprocs = ompi_comm_size(comm);

    for (i = 0; 
        (i < comm->c_topo_comm->mtc_ndims_or_nnodes) && (i < maxdims); 
        ++i, ++d) {

        dim = (*d > 0) ? *d : -(*d);
        remprocs /= dim;
        *coords++ = rank / remprocs;
        rank %= remprocs;
    }

    return MPI_SUCCESS;
}