/* -*- 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"
/* Local gather remote send
*
* Remote group does a local intracommunicator gather to rank 0. Rank
* 0 then sends data to root.
*
* Cost: (lgp+1).alpha + n.((p-1)/p).beta + n.beta
*/
#undef FUNCNAME
#define FUNCNAME MPIR_Gather_inter_local_gather_remote_send
#undef FCNAME
#define FCNAME MPL_QUOTE(FUNCNAME)
int MPIR_Gather_inter_local_gather_remote_send(const void *sendbuf, int sendcount,
MPI_Datatype sendtype, void *recvbuf, int recvcount,
MPI_Datatype recvtype, int root,
MPIR_Comm * comm_ptr, MPIR_Errflag_t * errflag)
{
int rank, local_size, remote_size, mpi_errno = MPI_SUCCESS;
int mpi_errno_ret = MPI_SUCCESS;
MPI_Status status;
MPI_Aint extent, true_extent, true_lb = 0;
void *tmp_buf = NULL;
MPIR_Comm *newcomm_ptr = NULL;
MPIR_CHKLMEM_DECL(1);
if (root == MPI_PROC_NULL) {
/* local processes other than root do nothing */
return MPI_SUCCESS;
}
remote_size = comm_ptr->remote_size;
local_size = comm_ptr->local_size;
if (root == MPI_ROOT) {
/* root receives data from rank 0 on remote group */
mpi_errno =
MPIC_Recv(recvbuf, recvcount * remote_size, recvtype, 0, MPIR_GATHER_TAG, comm_ptr,
&status, 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);
}
} else {
/* remote group. Rank 0 allocates temporary buffer, does
* local intracommunicator gather, and then sends the data
* to root. */
rank = comm_ptr->rank;
if (rank == 0) {
MPIR_Type_get_true_extent_impl(sendtype, &true_lb, &true_extent);
MPIR_Datatype_get_extent_macro(sendtype, extent);
MPIR_Ensure_Aint_fits_in_pointer(sendcount * local_size *
(MPL_MAX(extent, true_extent)));
MPIR_CHKLMEM_MALLOC(tmp_buf, void *,
sendcount * local_size * (MPL_MAX(extent, true_extent)), mpi_errno,
"tmp_buf", MPL_MEM_BUFFER);
/* adjust for potential negative lower bound in datatype */
tmp_buf = (void *) ((char *) tmp_buf - true_lb);
}
/* all processes in remote group form new intracommunicator */
if (!comm_ptr->local_comm) {
mpi_errno = MPII_Setup_intercomm_localcomm(comm_ptr);
if (mpi_errno)
MPIR_ERR_POP(mpi_errno);
}
newcomm_ptr = comm_ptr->local_comm;
/* now do the a local gather on this intracommunicator */
mpi_errno =
MPIR_Gather(sendbuf, sendcount, sendtype, tmp_buf, sendcount, sendtype, 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);
}
if (rank == 0) {
mpi_errno =
MPIC_Send(tmp_buf, sendcount * local_size, sendtype, root, MPIR_GATHER_TAG,
comm_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;
}