comparison src/fftw-3.3.8/rdft/rdft-dht.c @ 167:bd3cc4d1df30

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
+ *
+ */
+
+
+/* Solve an R2HC/HC2R problem via post/pre processing of a DHT.  This
+   is mainly useful because we can use Rader to compute DHTs of prime
+   sizes.  It also allows us to express hc2r problems in terms of r2hc
+   (via dht-r2hc), and to do hc2r problems without destroying the input. */
+
+#include "rdft/rdft.h"
+
+typedef struct {
+     solver super;
+} S;
+
+typedef struct {
+     plan_rdft super;
+     plan *cld;
+     INT is, os;
+     INT n;
+} P;
+
+static void apply_r2hc(const plan *ego_, R *I, R *O)
+{
+     const P *ego = (const P *) ego_;
+     INT os;
+     INT i, n;
+
+     {
+	  plan_rdft *cld = (plan_rdft *) ego->cld;
+	  cld->apply((plan *) cld, I, O);
+     }
+
+     n = ego->n;
+     os = ego->os;
+     for (i = 1; i < n - i; ++i) {
+	  E a, b;
+	  a = K(0.5) * O[os * i];
+	  b = K(0.5) * O[os * (n - i)];
+	  O[os * i] = a + b;
+#if FFT_SIGN == -1
+	  O[os * (n - i)] = b - a;
+#else
+	  O[os * (n - i)] = a - b;
+#endif
+     }
+}
+
+/* hc2r, destroying input as usual */
+static void apply_hc2r(const plan *ego_, R *I, R *O)
+{
+     const P *ego = (const P *) ego_;
+     INT is = ego->is;
+     INT i, n = ego->n;
+
+     for (i = 1; i < n - i; ++i) {
+	  E a, b;
+	  a = I[is * i];
+	  b = I[is * (n - i)];
+#if FFT_SIGN == -1
+	  I[is * i] = a - b;
+	  I[is * (n - i)] = a + b;
+#else
+	  I[is * i] = a + b;
+	  I[is * (n - i)] = a - b;
+#endif
+     }
+
+     {
+	  plan_rdft *cld = (plan_rdft *) ego->cld;
+	  cld->apply((plan *) cld, I, O);
+     }
+}
+
+/* hc2r, without destroying input */
+static void apply_hc2r_save(const plan *ego_, R *I, R *O)
+{
+     const P *ego = (const P *) ego_;
+     INT is = ego->is, os = ego->os;
+     INT i, n = ego->n;
+
+     O[0] = I[0];
+     for (i = 1; i < n - i; ++i) {
+	  E a, b;
+	  a = I[is * i];
+	  b = I[is * (n - i)];
+#if FFT_SIGN == -1
+	  O[os * i] = a - b;
+	  O[os * (n - i)] = a + b;
+#else
+	  O[os * i] = a + b;
+	  O[os * (n - i)] = a - b;
+#endif
+     }
+     if (i == n - i)
+	  O[os * i] = I[is * i];
+
+     {
+	  plan_rdft *cld = (plan_rdft *) ego->cld;
+	  cld->apply((plan *) cld, O, O);
+     }
+}
+
+static void awake(plan *ego_, enum wakefulness wakefulness)
+{
+     P *ego = (P *) ego_;
+     X(plan_awake)(ego->cld, wakefulness);
+}
+
+static void destroy(plan *ego_)
+{
+     P *ego = (P *) ego_;
+     X(plan_destroy_internal)(ego->cld);
+}
+
+static void print(const plan *ego_, printer *p)
+{
+     const P *ego = (const P *) ego_;
+     p->print(p, "(%s-dht-%D%(%p%))", 
+	      ego->super.apply == apply_r2hc ? "r2hc" : "hc2r",
+	      ego->n, ego->cld);
+}
+
+static int applicable0(const solver *ego_, const problem *p_)
+{
+     const problem_rdft *p = (const problem_rdft *) p_;
+     UNUSED(ego_);
+
+     return (1
+	     && p->sz->rnk == 1
+	     && p->vecsz->rnk == 0
+	     && (p->kind[0] == R2HC || p->kind[0] == HC2R)
+
+	     /* hack: size-2 DHT etc. are defined as being equivalent
+		to size-2 R2HC in problem.c, so we need this to prevent
+		infinite loops for size 2 in EXHAUSTIVE mode: */
+	     && p->sz->dims[0].n > 2
+	  );
+}
+
+static int applicable(const solver *ego, const problem *p_, 
+		      const planner *plnr)
+{
+     return (!NO_SLOWP(plnr) && applicable0(ego, p_));
+}
+
+static plan *mkplan(const solver *ego_, const problem *p_, planner *plnr)
+{
+     P *pln;
+     const problem_rdft *p;
+     problem *cldp;
+     plan *cld;
+
+     static const plan_adt padt = {
+	  X(rdft_solve), awake, print, destroy
+     };
+
+     if (!applicable(ego_, p_, plnr))
+          return (plan *)0;
+
+     p = (const problem_rdft *) p_;
+
+     if (p->kind[0] == R2HC || !NO_DESTROY_INPUTP(plnr))
+	  cldp = X(mkproblem_rdft_1)(p->sz, p->vecsz, p->I, p->O, DHT);
+     else {
+	  tensor *sz = X(tensor_copy_inplace)(p->sz, INPLACE_OS);
+	  cldp = X(mkproblem_rdft_1)(sz, p->vecsz, p->O, p->O, DHT);
+	  X(tensor_destroy)(sz);
+     }
+     cld = X(mkplan_d)(plnr, cldp);
+     if (!cld) return (plan *)0;
+
+     pln = MKPLAN_RDFT(P, &padt, p->kind[0] == R2HC ? 
+		       apply_r2hc : (NO_DESTROY_INPUTP(plnr) ?
+				     apply_hc2r_save : apply_hc2r));
+     pln->n = p->sz->dims[0].n;
+     pln->is = p->sz->dims[0].is;
+     pln->os = p->sz->dims[0].os;
+     pln->cld = cld;
+     
+     pln->super.super.ops = cld->ops;
+     pln->super.super.ops.other += 4 * ((pln->n - 1)/2);
+     pln->super.super.ops.add += 2 * ((pln->n - 1)/2);
+     if (p->kind[0] == R2HC)
+	  pln->super.super.ops.mul += 2 * ((pln->n - 1)/2);
+     if (pln->super.apply == apply_hc2r_save)
+	  pln->super.super.ops.other += 2 + (pln->n % 2 ? 0 : 2);
+
+     return &(pln->super.super);
+}
+
+/* constructor */
+static solver *mksolver(void)
+{
+     static const solver_adt sadt = { PROBLEM_RDFT, mkplan, 0 };
+     S *slv = MKSOLVER(S, &sadt);
+     return &(slv->super);
+}
+
+void X(rdft_dht_register)(planner *p)
+{
+     REGISTER_SOLVER(p, mksolver());
+}