comparison src/fftw-3.3.8/kernel/tensor7.c @ 82:d0c2a83c1364

Add FFTW 3.3.8 source, and a Linux build

+/*
+ * 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 "kernel/ifftw.h"
+
+static int signof(INT x)
+{
+     if (x < 0) return -1;
+     if (x == 0) return 0;
+     /* if (x > 0) */ return 1;
+}
+
+/* total order among iodim's */
+int X(dimcmp)(const iodim *a, const iodim *b)
+{
+     INT sai = X(iabs)(a->is), sbi = X(iabs)(b->is);
+     INT sao = X(iabs)(a->os), sbo = X(iabs)(b->os);
+     INT sam = X(imin)(sai, sao), sbm = X(imin)(sbi, sbo);
+
+     /* in descending order of min{istride, ostride} */
+     if (sam != sbm)
+	  return signof(sbm - sam);
+
+     /* in case of a tie, in descending order of istride */
+     if (sbi != sai)
+          return signof(sbi - sai);
+
+     /* in case of a tie, in descending order of ostride */
+     if (sbo != sao)
+          return signof(sbo - sao);
+
+     /* in case of a tie, in ascending order of n */
+     return signof(a->n - b->n);
+}
+
+static void canonicalize(tensor *x)
+{
+     if (x->rnk > 1) {
+	  qsort(x->dims, (unsigned)x->rnk, sizeof(iodim),
+		(int (*)(const void *, const void *))X(dimcmp));
+     }
+}
+
+static int compare_by_istride(const iodim *a, const iodim *b)
+{
+     INT sai = X(iabs)(a->is), sbi = X(iabs)(b->is);
+
+     /* in descending order of istride */
+     return signof(sbi - sai);
+}
+
+static tensor *really_compress(const tensor *sz)
+{
+     int i, rnk;
+     tensor *x;
+
+     A(FINITE_RNK(sz->rnk));
+     for (i = rnk = 0; i < sz->rnk; ++i) {
+          A(sz->dims[i].n > 0);
+          if (sz->dims[i].n != 1)
+               ++rnk;
+     }
+
+     x = X(mktensor)(rnk);
+     for (i = rnk = 0; i < sz->rnk; ++i) {
+          if (sz->dims[i].n != 1)
+               x->dims[rnk++] = sz->dims[i];
+     }
+     return x;
+}
+
+/* Like tensor_copy, but eliminate n == 1 dimensions, which
+   never affect any transform or transform vector.
+ 
+   Also, we sort the tensor into a canonical order of decreasing
+   strides (see X(dimcmp) for an exact definition).  In general,
+   processing a loop/array in order of decreasing stride will improve
+   locality.  Both forward and backwards traversal of the tensor are
+   considered e.g. by vrank-geq1, so sorting in increasing
+   vs. decreasing order is not really important. */
+tensor *X(tensor_compress)(const tensor *sz)
+{
+     tensor *x = really_compress(sz);
+     canonicalize(x);
+     return x;
+}
+
+/* Return whether the strides of a and b are such that they form an
+   effective contiguous 1d array.  Assumes that a.is >= b.is. */
+static int strides_contig(iodim *a, iodim *b)
+{
+     return (a->is == b->is * b->n && a->os == b->os * b->n);
+}
+
+/* Like tensor_compress, but also compress into one dimension any
+   group of dimensions that form a contiguous block of indices with
+   some stride.  (This can safely be done for transform vector sizes.) */
+tensor *X(tensor_compress_contiguous)(const tensor *sz)
+{
+     int i, rnk;
+     tensor *sz2, *x;
+
+     if (X(tensor_sz)(sz) == 0) 
+	  return X(mktensor)(RNK_MINFTY);
+
+     sz2 = really_compress(sz);
+     A(FINITE_RNK(sz2->rnk));
+
+     if (sz2->rnk <= 1) { /* nothing to compress. */ 
+	  if (0) {
+	       /* this call is redundant, because "sz->rnk <= 1" implies
+		  that the tensor is already canonical, but I am writing
+		  it explicitly because "logically" we need to canonicalize
+		  the tensor before returning. */
+	       canonicalize(sz2);
+	  }
+          return sz2;
+     }
+
+     /* sort in descending order of |istride|, so that compressible
+	dimensions appear contigously */
+     qsort(sz2->dims, (unsigned)sz2->rnk, sizeof(iodim),
+		(int (*)(const void *, const void *))compare_by_istride);
+
+     /* compute what the rank will be after compression */
+     for (i = rnk = 1; i < sz2->rnk; ++i)
+          if (!strides_contig(sz2->dims + i - 1, sz2->dims + i))
+               ++rnk;
+
+     /* merge adjacent dimensions whenever possible */
+     x = X(mktensor)(rnk);
+     x->dims[0] = sz2->dims[0];
+     for (i = rnk = 1; i < sz2->rnk; ++i) {
+          if (strides_contig(sz2->dims + i - 1, sz2->dims + i)) {
+               x->dims[rnk - 1].n *= sz2->dims[i].n;
+               x->dims[rnk - 1].is = sz2->dims[i].is;
+               x->dims[rnk - 1].os = sz2->dims[i].os;
+          } else {
+               A(rnk < x->rnk);
+               x->dims[rnk++] = sz2->dims[i];
+          }
+     }
+
+     X(tensor_destroy)(sz2);
+
+     /* reduce to canonical form */
+     canonicalize(x);
+     return x;
+}
+
+/* The inverse of X(tensor_append): splits the sz tensor into
+   tensor a followed by tensor b, where a's rank is arnk. */
+void X(tensor_split)(const tensor *sz, tensor **a, int arnk, tensor **b)
+{
+     A(FINITE_RNK(sz->rnk) && FINITE_RNK(arnk));
+
+     *a = X(tensor_copy_sub)(sz, 0, arnk);
+     *b = X(tensor_copy_sub)(sz, arnk, sz->rnk - arnk);
+}
+
+/* TRUE if the two tensors are equal */
+int X(tensor_equal)(const tensor *a, const tensor *b)
+{
+     if (a->rnk != b->rnk)
+	  return 0;
+
+     if (FINITE_RNK(a->rnk)) {
+	  int i;
+	  for (i = 0; i < a->rnk; ++i) 
+	       if (0
+		   || a->dims[i].n != b->dims[i].n
+		   || a->dims[i].is != b->dims[i].is
+		   || a->dims[i].os != b->dims[i].os
+		    )
+		    return 0;
+     }
+
+     return 1;
+}
+
+/* TRUE if the sets of input and output locations described by
+   (append sz vecsz) are the same */
+int X(tensor_inplace_locations)(const tensor *sz, const tensor *vecsz)
+{
+     tensor *t = X(tensor_append)(sz, vecsz);
+     tensor *ti = X(tensor_copy_inplace)(t, INPLACE_IS);
+     tensor *to = X(tensor_copy_inplace)(t, INPLACE_OS);
+     tensor *tic = X(tensor_compress_contiguous)(ti);
+     tensor *toc = X(tensor_compress_contiguous)(to);
+
+     int retval = X(tensor_equal)(tic, toc);
+
+     X(tensor_destroy)(t);
+     X(tensor_destroy4)(ti, to, tic, toc);
+
+     return retval;
+}