/* -*- 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_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
#elif defined(HAVE_WEAK_ATTRIBUTE)
int MPI_Cart_sub(MPI_Comm comm, const int remain_dims[], MPI_Comm * newcomm)
__attribute__ ((weak, alias("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
#undef MPI_Cart_sub
#define MPI_Cart_sub PMPI_Cart_sub
#endif
#undef FUNCNAME
#define FUNCNAME MPI_Cart_sub
#undef FCNAME
#define FCNAME MPL_QUOTE(FUNCNAME)
/*@
MPI_Cart_sub - Partitions a communicator into subgroups which
form lower-dimensional cartesian subgrids
Input Parameters:
+ comm - communicator with cartesian structure (handle)
- remain_dims - the 'i'th entry of remain_dims specifies whether the 'i'th
dimension is kept in the subgrid (true) or is dropped (false) (logical
vector)
Output Parameters:
. newcomm - communicator containing the subgrid that includes the calling
process (handle)
.N ThreadSafe
.N Fortran
.N Errors
.N MPI_SUCCESS
.N MPI_ERR_TOPOLOGY
.N MPI_ERR_COMM
.N MPI_ERR_ARG
@*/
int MPI_Cart_sub(MPI_Comm comm, const int remain_dims[], MPI_Comm * newcomm)
{
int mpi_errno = MPI_SUCCESS, all_false;
int ndims, key, color, ndims_in_subcomm, nnodes_in_subcomm, i, j, rank;
MPIR_Comm *comm_ptr = NULL, *newcomm_ptr;
MPIR_Topology *topo_ptr, *toponew_ptr;
MPIR_CHKPMEM_DECL(4);
MPIR_FUNC_TERSE_STATE_DECL(MPID_STATE_MPI_CART_SUB);
MPIR_ERRTEST_INITIALIZED_ORDIE();
MPID_THREAD_CS_ENTER(GLOBAL, MPIR_THREAD_GLOBAL_ALLFUNC_MUTEX);
MPIR_FUNC_TERSE_ENTER(MPID_STATE_MPI_CART_SUB);
/* 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 comm_ptr is not valid, it will be reset to null */
if (mpi_errno)
goto fn_fail;
}
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);
MPIR_ERR_CHKANDJUMP(!topo_ptr, mpi_errno, MPI_ERR_TOPOLOGY, "**notopology");
MPIR_ERR_CHKANDJUMP(topo_ptr->kind != MPI_CART, mpi_errno, MPI_ERR_TOPOLOGY, "**notcarttopo");
ndims = topo_ptr->topo.cart.ndims;
all_false = 1; /* all entries in remain_dims are false */
for (i = 0; i < ndims; i++) {
if (remain_dims[i]) {
/* any 1 is true, set flag to 0 and break */
all_false = 0;
break;
}
}
if (all_false) {
/* ndims=0, or all entries in remain_dims are false.
* MPI 2.1 says return a 0D Cartesian topology. */
mpi_errno = MPIR_Cart_create_impl(comm_ptr, 0, NULL, NULL, 0, newcomm);
if (mpi_errno)
MPIR_ERR_POP(mpi_errno);
} else {
/* Determine the number of remaining dimensions */
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];
}
}
mpi_errno = MPIR_Comm_split_impl(comm_ptr, color, key, &newcomm_ptr);
if (mpi_errno)
MPIR_ERR_POP(mpi_errno);
*newcomm = newcomm_ptr->handle;
/* Save the topology of this new communicator */
MPIR_CHKPMEM_MALLOC(toponew_ptr, MPIR_Topology *, sizeof(MPIR_Topology),
mpi_errno, "toponew_ptr", MPL_MEM_COMM);
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) {
MPIR_CHKPMEM_MALLOC(toponew_ptr->topo.cart.dims, int *,
ndims_in_subcomm * sizeof(int), mpi_errno, "cart.dims",
MPL_MEM_COMM);
MPIR_CHKPMEM_MALLOC(toponew_ptr->topo.cart.periodic, int *,
ndims_in_subcomm * sizeof(int), mpi_errno, "cart.periodic",
MPL_MEM_COMM);
MPIR_CHKPMEM_MALLOC(toponew_ptr->topo.cart.position, int *,
ndims_in_subcomm * sizeof(int), mpi_errno, "cart.position",
MPL_MEM_COMM);
} 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++;
}
}
/* 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)
goto fn_fail;
}
/* ... end of body of routine ... */
fn_exit:
MPIR_FUNC_TERSE_EXIT(MPID_STATE_MPI_CART_SUB);
MPID_THREAD_CS_EXIT(GLOBAL, MPIR_THREAD_GLOBAL_ALLFUNC_MUTEX);
return mpi_errno;
fn_fail:
/* --BEGIN ERROR HANDLING-- */
MPIR_CHKPMEM_REAP();
#ifdef HAVE_ERROR_CHECKING
{
mpi_errno =
MPIR_Err_create_code(mpi_errno, MPIR_ERR_RECOVERABLE, FCNAME, __LINE__, MPI_ERR_OTHER,
"**mpi_cart_sub", "**mpi_cart_sub %C %p %p", comm, remain_dims,
newcomm);
}
#endif
mpi_errno = MPIR_Err_return_comm(comm_ptr, FCNAME, mpi_errno);
goto fn_exit;
/* --END ERROR HANDLING-- */
}