comparison src/fftw-3.3.3/kernel/pickdim.c @ 95:89f5e221ed7b

Add FFTW3

+/*
+ * Copyright (c) 2003, 2007-11 Matteo Frigo
+ * Copyright (c) 2003, 2007-11 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.h"
+
+
+/* Given a solver which_dim, a vector sz, and whether or not the
+   transform is out-of-place, return the actual dimension index that
+   it corresponds to.  The basic idea here is that we return the
+   which_dim'th valid dimension, starting from the end if
+   which_dim < 0. */
+static int really_pickdim(int which_dim, const tensor *sz, int oop, int *dp)
+{
+     int i;
+     int count_ok = 0;
+     if (which_dim > 0) {
+          for (i = 0; i < sz->rnk; ++i) {
+               if (oop || sz->dims[i].is == sz->dims[i].os)
+                    if (++count_ok == which_dim) {
+                         *dp = i;
+                         return 1;
+                    }
+          }
+     }
+     else if (which_dim < 0) {
+          for (i = sz->rnk - 1; i >= 0; --i) {
+               if (oop || sz->dims[i].is == sz->dims[i].os)
+                    if (++count_ok == -which_dim) {
+                         *dp = i;
+                         return 1;
+                    }
+          }
+     }
+     else { /* zero: pick the middle, if valid */
+	  i = (sz->rnk - 1) / 2;
+	  if (i >= 0 && (oop || sz->dims[i].is == sz->dims[i].os)) {
+	       *dp = i;
+	       return 1;
+	  }
+     }
+     return 0;
+}
+
+/* Like really_pickdim, but only returns 1 if no previous "buddy"
+   which_dim in the buddies list would give the same dim. */
+int X(pickdim)(int which_dim, const int *buddies, int nbuddies,
+	       const tensor *sz, int oop, int *dp)
+{
+     int i, d1;
+
+     if (!really_pickdim(which_dim, sz, oop, dp))
+          return 0;
+
+     /* check whether some buddy solver would produce the same dim.
+        If so, consider this solver unapplicable and let the buddy
+        take care of it.  The smallest-indexed buddy is applicable. */
+     for (i = 0; i < nbuddies; ++i) {
+          if (buddies[i] == which_dim)
+               break;  /* found self */
+          if (really_pickdim(buddies[i], sz, oop, &d1) && *dp == d1)
+               return 0; /* found equivalent buddy */
+     }
+     return 1;
+}