/* -*- 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"
/* Intercommunicator Allreduce
*
* We first do intracommunicator reduces to rank 0 on left and right
* groups, then an exchange between left and right rank 0, and finally
* intracommunicator broadcasts from rank 0 on left and right
* group.
*/
#undef FUNCNAME
#define FUNCNAME MPIR_Allreduce_inter_reduce_exchange_bcast
#undef FCNAME
#define FCNAME MPL_QUOTE(FUNCNAME)
int MPIR_Allreduce_inter_reduce_exchange_bcast(const void *sendbuf, void *recvbuf, int
count, MPI_Datatype datatype, MPI_Op op,
MPIR_Comm * comm_ptr, MPIR_Errflag_t * errflag)
{
int mpi_errno;
int mpi_errno_ret = MPI_SUCCESS;
MPI_Aint true_extent, true_lb, extent;
void *tmp_buf = NULL;
MPIR_Comm *newcomm_ptr = NULL;
MPIR_CHKLMEM_DECL(1);
if (comm_ptr->rank == 0) {
MPIR_Type_get_true_extent_impl(datatype, &true_lb, &true_extent);
MPIR_Datatype_get_extent_macro(datatype, extent);
/* I think this is the worse case, so we can avoid an assert()
* inside the for loop */
/* Should MPIR_CHKLMEM_MALLOC do this? */
MPIR_Ensure_Aint_fits_in_pointer(count * MPL_MAX(extent, true_extent));
MPIR_CHKLMEM_MALLOC(tmp_buf, void *, count * (MPL_MAX(extent, true_extent)), mpi_errno,
"temporary buffer", MPL_MEM_BUFFER);
/* adjust for potential negative lower bound in datatype */
tmp_buf = (void *) ((char *) tmp_buf - true_lb);
}
/* Get the local intracommunicator */
if (!comm_ptr->local_comm)
MPII_Setup_intercomm_localcomm(comm_ptr);
newcomm_ptr = comm_ptr->local_comm;
/* Do a local reduce on this intracommunicator */
mpi_errno = MPIR_Reduce(sendbuf, tmp_buf, count, datatype, op, 0, newcomm_ptr, errflag);
if (mpi_errno) {
/* for communication errors, just record the error but continue */
*errflag =
MPIX_ERR_PROC_FAILED ==
MPIR_ERR_GET_CLASS(mpi_errno) ? MPIR_ERR_PROC_FAILED : MPIR_ERR_OTHER;
MPIR_ERR_SET(mpi_errno, *errflag, "**fail");
MPIR_ERR_ADD(mpi_errno_ret, mpi_errno);
}
/* Do a exchange between local and remote rank 0 on this intercommunicator */
if (comm_ptr->rank == 0) {
mpi_errno = MPIC_Sendrecv(tmp_buf, count, datatype, 0, MPIR_REDUCE_TAG,
recvbuf, count, datatype, 0, MPIR_REDUCE_TAG,
comm_ptr, MPI_STATUS_IGNORE, errflag);
if (mpi_errno) {
/* for communication errors, just record the error but continue */
*errflag =
MPIX_ERR_PROC_FAILED ==
MPIR_ERR_GET_CLASS(mpi_errno) ? MPIR_ERR_PROC_FAILED : MPIR_ERR_OTHER;
MPIR_ERR_SET(mpi_errno, *errflag, "**fail");
MPIR_ERR_ADD(mpi_errno_ret, mpi_errno);
}
}
/* Do a local broadcast on this intracommunicator */
mpi_errno = MPIR_Bcast(recvbuf, count, datatype, 0, newcomm_ptr, errflag);
if (mpi_errno) {
/* for communication errors, just record the error but continue */
*errflag =
MPIX_ERR_PROC_FAILED ==
MPIR_ERR_GET_CLASS(mpi_errno) ? MPIR_ERR_PROC_FAILED : MPIR_ERR_OTHER;
MPIR_ERR_SET(mpi_errno, *errflag, "**fail");
MPIR_ERR_ADD(mpi_errno_ret, mpi_errno);
}
fn_exit:
MPIR_CHKLMEM_FREEALL();
if (mpi_errno_ret)
mpi_errno = mpi_errno_ret;
else if (*errflag != MPIR_ERR_NONE)
MPIR_ERR_SET(mpi_errno, *errflag, "**coll_fail");
return mpi_errno;
fn_fail:
goto fn_exit;
}