cart_sub.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_Cart_sub */
#if defined(HAVE_PRAGMA_WEAK)
#pragma weak MPI_Cart_sub = PMPI_Cart_sub
#elif defined(HAVE_PRAGMA_HP_SEC_DEF)
#pragma _HP_SECONDARY_DEF PMPI_Cart_sub  MPI_Cart_sub
#elif defined(HAVE_PRAGMA_CRI_DUP)
#pragma _CRI duplicate MPI_Cart_sub as PMPI_Cart_sub
#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_Cart_sub PMPI_Cart_sub

#endif

#undef FUNCNAME
#define FUNCNAME MPI_Cart_sub

/*@
   MPI_Cart_sub - cart_sub

   Arguments:
+  MPI_Comm comm - communicator
.  int *remain_dims - remain_dims
-  MPI_Comm *comm_new - new communicator

   Notes:

.N Fortran

.N Errors
.N MPI_SUCCESS
@*/
int MPI_Cart_sub(MPI_Comm comm, int *remain_dims, MPI_Comm *comm_new)
{
    static const char FCNAME[] = "MPI_Cart_sub";
    int mpi_errno = MPI_SUCCESS;
    int ndims, key, color, ndims_in_subcomm, nnodes_in_subcomm, i, j, rank;
    MPID_Comm *comm_ptr = NULL, *newcomm_ptr;
    MPIR_Topology *topo_ptr, *toponew_ptr;
    MPID_MPI_STATE_DECL(MPID_STATE_MPI_CART_SUB);

    MPID_MPI_FUNC_ENTER(MPID_STATE_MPI_CART_SUB);
    /* 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 */
            if (mpi_errno) {
                MPID_MPI_FUNC_EXIT(MPID_STATE_MPI_CART_SUB);
                return MPIR_Err_return_comm( comm_ptr, FCNAME, mpi_errno );
            }
        }
        MPID_END_ERROR_CHECKS;
    }
#   endif /* HAVE_ERROR_CHECKING */

    /* ... body of routine ...  */
    
    /* Check that the communicator already has a Cartesian topology */
    topo_ptr = MPIR_Topology_get( comm_ptr );

    if (!topo_ptr) {
	mpi_errno = MPIR_Err_create_code( MPI_ERR_TOPOLOGY, "**notopology", 0 );
    }
    else if (topo_ptr->kind != MPI_CART) {
	mpi_errno = MPIR_Err_create_code( MPI_ERR_TOPOLOGY, "**notcarttopo", 0 );
    }
    if (mpi_errno) {
	MPID_MPI_FUNC_EXIT(MPID_STATE_MPI_CART_SUB);
	return MPIR_Err_return_comm( comm_ptr, FCNAME, mpi_errno );
    }

    /* Determine the number of remaining dimensions */
    ndims = topo_ptr->topo.cart.ndims;
    ndims_in_subcomm = 0;
    nnodes_in_subcomm = 1;
    for (i=0; i<ndims; i++) {
	if (remain_dims[i]) {
	    ndims_in_subcomm ++;
	    nnodes_in_subcomm *= topo_ptr->topo.cart.dims[i];
	}
    }

    /* Split this communicator.  Do this even if there are no remaining
       dimensions so that the topology information is attached */
    key   = 0;
    color = 0;
    for (i=0; i<ndims; i++) {
	if (remain_dims[i]) {
	    key = (key * topo_ptr->topo.cart.dims[i]) + topo_ptr->topo.cart.position[i];
	}
	else {
	    color = (color * topo_ptr->topo.cart.dims[i]) + topo_ptr->topo.cart.position[i];
	}
    }
    MPIR_Nest_incr();
    mpi_errno = NMPI_Comm_split( comm, color, key, comm_new );
    MPIR_Nest_decr();
    if (mpi_errno) {
	MPID_MPI_FUNC_EXIT(MPID_STATE_MPI_CART_SUB);
	return MPIR_Err_return_comm( comm_ptr, FCNAME, mpi_errno );
    }
    
    /* Save the topology of this new communicator */
    toponew_ptr = (MPIR_Topology *)MPIU_Malloc( sizeof( MPIR_Topology) );
    if (!toponew_ptr) {
	mpi_errno = MPIR_Err_create_code( MPI_ERR_OTHER, "**nomem", 0 );
	MPID_MPI_FUNC_EXIT(MPID_STATE_MPI_CART_SUB);
	return MPIR_Err_return_comm( comm_ptr, FCNAME, mpi_errno );
    }
	
    toponew_ptr->kind		  = MPI_CART;
    toponew_ptr->topo.cart.ndims  = ndims_in_subcomm;
    toponew_ptr->topo.cart.nnodes = nnodes_in_subcomm;
    if (ndims_in_subcomm) {
	toponew_ptr->topo.cart.dims     = (int *)MPIU_Malloc( ndims_in_subcomm * sizeof(int) );
	toponew_ptr->topo.cart.periodic = (int *)MPIU_Malloc( ndims_in_subcomm * sizeof(int) );
	toponew_ptr->topo.cart.position = (int *)MPIU_Malloc( ndims_in_subcomm * sizeof(int) );
	if (!toponew_ptr->topo.cart.dims || ! toponew_ptr->topo.cart.periodic ||
	    !toponew_ptr->topo.cart.position) {
	    mpi_errno = MPIR_Err_create_code( MPI_ERR_OTHER, "**nomem", 0 );
	    MPID_MPI_FUNC_EXIT(MPID_STATE_MPI_CART_SUB);
	    return MPIR_Err_return_comm( comm_ptr, FCNAME, mpi_errno );
	}
    }
    else {
	toponew_ptr->topo.cart.dims     = 0;
	toponew_ptr->topo.cart.periodic = 0;
	toponew_ptr->topo.cart.position = 0;
    }

    j = 0;
    for (i=0; i<ndims; i++) {
	if (remain_dims[i]) {
	    toponew_ptr->topo.cart.dims[j] = topo_ptr->topo.cart.dims[i];
	    toponew_ptr->topo.cart.periodic[j] = topo_ptr->topo.cart.periodic[i];
	    j++;
	}
    }

    MPID_Comm_get_ptr( *comm_new, newcomm_ptr );
    /* Compute the position of this process in the new communicator */
    rank = newcomm_ptr->rank;
    for (i=0; i<ndims_in_subcomm; i++) {
	nnodes_in_subcomm /= toponew_ptr->topo.cart.dims[i];
	toponew_ptr->topo.cart.position[i] = rank / nnodes_in_subcomm;
	rank = rank % nnodes_in_subcomm;
    }

    mpi_errno = MPIR_Topology_put( newcomm_ptr, toponew_ptr );
    if (mpi_errno) {
	MPID_MPI_FUNC_EXIT(MPID_STATE_MPI_CART_SUB);
	return MPIR_Err_return_comm( comm_ptr, FCNAME, mpi_errno );
    }

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