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-rw-r--r--src/fftw3/rdft/rdft-dht.c223
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diff --git a/src/fftw3/rdft/rdft-dht.c b/src/fftw3/rdft/rdft-dht.c
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+++ b/src/fftw3/rdft/rdft-dht.c
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+/*
+ * Copyright (c) 2003 Matteo Frigo
+ * Copyright (c) 2003 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+/* $Id: rdft-dht.c,v 1.1 2008/10/17 06:11:29 scuri Exp $ */
+
+/* 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.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_, int flg)
+{
+ P *ego = (P *) ego_;
+ AWAKE(ego->cld, flg);
+}
+
+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_)
+{
+ UNUSED(ego_);
+ if (RDFTP(p_)) {
+ const problem_rdft *p = (const problem_rdft *) p_;
+ 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
+ );
+ }
+ return 0;
+}
+
+static int applicable(const solver *ego, const problem *p_,
+ const planner *plnr)
+{
+ return (!NO_UGLYP(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 || 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 : (DESTROY_INPUTP(plnr) ?
+ apply_hc2r : apply_hc2r_save));
+ 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 = { mkplan };
+ S *slv = MKSOLVER(S, &sadt);
+ return &(slv->super);
+}
+
+void X(rdft_dht_register)(planner *p)
+{
+ REGISTER_SOLVER(p, mksolver());
+}
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