113 lines
3.8 KiB
C
113 lines
3.8 KiB
C
/*
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* Copyright (c) 2003, 2007-14 Matteo Frigo
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* Copyright (c) 2003, 2007-14 Massachusetts Institute of Technology
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*/
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#include "fftw3-mpi.h"
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#include "ifftw-mpi.h"
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#include <string.h>
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#if SIZEOF_SIZE_T == SIZEOF_UNSIGNED_INT
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# define FFTW_MPI_SIZE_T MPI_UNSIGNED
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#elif SIZEOF_SIZE_T == SIZEOF_UNSIGNED_LONG
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# define FFTW_MPI_SIZE_T MPI_UNSIGNED_LONG
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#elif SIZEOF_SIZE_T == SIZEOF_UNSIGNED_LONG_LONG
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# define FFTW_MPI_SIZE_T MPI_UNSIGNED_LONG_LONG
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#else
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# error MPI type for size_t is unknown
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# define FFTW_MPI_SIZE_T MPI_UNSIGNED_LONG
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#endif
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/* Import wisdom from all processes to process 0, as prelude to
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exporting a single wisdom file (this is convenient when we are
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running on identical processors, to avoid the annoyance of having
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per-process wisdom files). In order to make the time for this
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operation logarithmic in the number of processors (rather than
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linear), we employ a tree reduction algorithm. This means that the
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wisdom is modified on processes other than root, which shouldn't
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matter in practice. */
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void XM(gather_wisdom)(MPI_Comm comm_)
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{
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MPI_Comm comm, comm2;
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int my_pe, n_pes;
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char *wis;
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size_t wislen;
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MPI_Status status;
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MPI_Comm_dup(comm_, &comm);
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MPI_Comm_rank(comm, &my_pe);
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MPI_Comm_size(comm, &n_pes);
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if (n_pes > 2) { /* recursively split into even/odd processes */
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MPI_Comm_split(comm, my_pe % 2, my_pe, &comm2);
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XM(gather_wisdom)(comm2);
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MPI_Comm_free(&comm2);
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}
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if (n_pes > 1 && my_pe < 2) { /* import process 1 -> 0 */
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if (my_pe == 1) {
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wis = X(export_wisdom_to_string)();
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wislen = strlen(wis) + 1;
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MPI_Send(&wislen, 1, FFTW_MPI_SIZE_T, 0, 111, comm);
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MPI_Send(wis, wislen, MPI_CHAR, 0, 222, comm);
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free(wis);
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}
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else /* my_pe == 0 */ {
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MPI_Recv(&wislen, 1, FFTW_MPI_SIZE_T, 1, 111, comm, &status);
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wis = (char *) MALLOC(wislen * sizeof(char), OTHER);
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MPI_Recv(wis, wislen, MPI_CHAR, 1, 222, comm, &status);
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if (!X(import_wisdom_from_string)(wis))
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MPI_Abort(comm, 1);
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X(ifree)(wis);
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}
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}
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MPI_Comm_free(&comm);
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}
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/* broadcast wisdom from process 0 to all other processes; this
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is useful so that we can import wisdom once and not worry
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about parallel I/O or process-specific wisdom, although of
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course it assumes that all the processes have identical
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performance characteristics (i.e. identical hardware). */
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void XM(broadcast_wisdom)(MPI_Comm comm_)
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{
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MPI_Comm comm;
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int my_pe;
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char *wis;
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size_t wislen;
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MPI_Comm_dup(comm_, &comm);
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MPI_Comm_rank(comm, &my_pe);
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if (my_pe != 0) {
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MPI_Bcast(&wislen, 1, FFTW_MPI_SIZE_T, 0, comm);
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wis = (char *) MALLOC(wislen * sizeof(char), OTHER);
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MPI_Bcast(wis, wislen, MPI_CHAR, 0, comm);
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if (!X(import_wisdom_from_string)(wis))
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MPI_Abort(comm, 1);
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X(ifree)(wis);
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}
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else /* my_pe == 0 */ {
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wis = X(export_wisdom_to_string)();
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wislen = strlen(wis) + 1;
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MPI_Bcast(&wislen, 1, FFTW_MPI_SIZE_T, 0, comm);
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MPI_Bcast(wis, wislen, MPI_CHAR, 0, comm);
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X(free)(wis);
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}
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MPI_Comm_free(&comm);
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}
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