comparison src/fftw-3.3.5/mpi/wisdom-api.c @ 42:2cd0e3b3e1fd

Current fftw source

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