comparison src/fftw-3.3.5/mpi/block.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 "ifftw-mpi.h"
+
+INT XM(num_blocks)(INT n, INT block)
+{
+     return (n + block - 1) / block;
+}
+
+int XM(num_blocks_ok)(INT n, INT block, MPI_Comm comm)
+{
+     int n_pes;
+     MPI_Comm_size(comm, &n_pes);
+     return n_pes >= XM(num_blocks)(n, block);
+}
+
+/* Pick a default block size for dividing a problem of size n among
+   n_pes processes.  Divide as equally as possible, while minimizing
+   the maximum block size among the processes as well as the number of
+   processes with nonzero blocks. */
+INT XM(default_block)(INT n, int n_pes)
+{
+     return ((n + n_pes - 1) / n_pes);
+}
+
+/* For a given block size and dimension n, compute the block size 
+   on the given process. */
+INT XM(block)(INT n, INT block, int which_block)
+{
+     INT d = n - which_block * block;
+     return d <= 0 ? 0 : (d > block ? block : d);
+}
+
+static INT num_blocks_kind(const ddim *dim, block_kind k)
+{
+     return XM(num_blocks)(dim->n, dim->b[k]);
+}
+
+INT XM(num_blocks_total)(const dtensor *sz, block_kind k)
+{
+     if (FINITE_RNK(sz->rnk)) {
+	  int i;
+	  INT ntot = 1;
+	  for (i = 0; i < sz->rnk; ++i)
+	       ntot *= num_blocks_kind(sz->dims + i, k);
+	  return ntot;
+     }
+     else
+	  return 0;
+}
+
+int XM(idle_process)(const dtensor *sz, block_kind k, int which_pe)
+{
+     return (which_pe >= XM(num_blocks_total)(sz, k));
+}
+
+/* Given a non-idle process which_pe, computes the coordinate
+   vector coords[rnk] giving the coordinates of a block in the
+   matrix of blocks.  k specifies whether we are talking about
+   the input or output data distribution. */
+void XM(block_coords)(const dtensor *sz, block_kind k, int which_pe, 
+		     INT *coords)
+{
+     int i;
+     A(!XM(idle_process)(sz, k, which_pe) && FINITE_RNK(sz->rnk));
+     for (i = sz->rnk - 1; i >= 0; --i) {
+	  INT nb = num_blocks_kind(sz->dims + i, k);
+	  coords[i] = which_pe % nb;
+	  which_pe /= nb;
+     }
+}
+
+INT XM(total_block)(const dtensor *sz, block_kind k, int which_pe)
+{
+     if (XM(idle_process)(sz, k, which_pe))
+	  return 0;
+     else {
+	  int i;
+	  INT N = 1, *coords;
+	  STACK_MALLOC(INT*, coords, sizeof(INT) * sz->rnk);
+	  XM(block_coords)(sz, k, which_pe, coords);
+	  for (i = 0; i < sz->rnk; ++i)
+	       N *= XM(block)(sz->dims[i].n, sz->dims[i].b[k], coords[i]);
+	  STACK_FREE(coords);
+	  return N;
+     }
+}
+
+/* returns whether sz is local for dims >= dim */
+int XM(is_local_after)(int dim, const dtensor *sz, block_kind k)
+{
+     if (FINITE_RNK(sz->rnk))
+	  for (; dim < sz->rnk; ++dim)
+	       if (XM(num_blocks)(sz->dims[dim].n, sz->dims[dim].b[k]) > 1)
+		    return 0;
+     return 1;
+}
+
+int XM(is_local)(const dtensor *sz, block_kind k)
+{
+     return XM(is_local_after)(0, sz, k);
+}
+
+/* Return whether sz is distributed for k according to a simple
+   1d block distribution in the first or second dimensions */
+int XM(is_block1d)(const dtensor *sz, block_kind k)
+{
+     int i;
+     if (!FINITE_RNK(sz->rnk)) return 0;
+     for (i = 0; i < sz->rnk && num_blocks_kind(sz->dims + i, k) == 1; ++i) ;
+     return(i < sz->rnk && i < 2 && XM(is_local_after)(i + 1, sz, k));
+
+}