From 5a422aba704c375a307a902bafe658342e209906 Mon Sep 17 00:00:00 2001 From: scuri Date: Fri, 17 Oct 2008 06:10:15 +0000 Subject: First commit - moving from LuaForge to SourceForge --- src/fftw3/reodft/reodft11e-r2hc.c | 295 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 295 insertions(+) create mode 100644 src/fftw3/reodft/reodft11e-r2hc.c (limited to 'src/fftw3/reodft/reodft11e-r2hc.c') diff --git a/src/fftw3/reodft/reodft11e-r2hc.c b/src/fftw3/reodft/reodft11e-r2hc.c new file mode 100644 index 0000000..d4366e3 --- /dev/null +++ b/src/fftw3/reodft/reodft11e-r2hc.c @@ -0,0 +1,295 @@ +/* + * 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: reodft11e-r2hc.c,v 1.1 2008/10/17 06:13:18 scuri Exp $ */ + +/* Do an R{E,O}DFT11 problem via an R2HC problem, with some + pre/post-processing ala FFTPACK. Use a trick from: + + S. C. Chan and K. L. Ho, "Direct methods for computing discrete + sinusoidal transforms," IEE Proceedings F 137 (6), 433--442 (1990). + + to re-express as an REDFT01 (DCT-III) problem. + + NOTE: We no longer use this algorithm, because it turns out to suffer + a catastrophic loss of accuracy for certain inputs, apparently because + its post-processing multiplies the output by a cosine. Near the zero + of the cosine, the REDFT01 must produce a near-singular output. +*/ + +#include "reodft.h" + +typedef struct { + solver super; +} S; + +typedef struct { + plan_rdft super; + plan *cld; + twid *td, *td2; + int is, os; + int n; + int vl; + int ivs, ovs; + rdft_kind kind; +} P; + +static void apply_re11(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; + int iv, vl = ego->vl; + int ivs = ego->ivs, ovs = ego->ovs; + R *W; + R *buf; + E cur; + + buf = (R *) MALLOC(sizeof(R) * n, BUFFERS); + + for (iv = 0; iv < vl; ++iv, I += ivs, O += ovs) { + /* I wish that this didn't require an extra pass. */ + /* FIXME: use recursive/cascade summation for better stability? */ + buf[n - 1] = cur = K(2.0) * I[is * (n - 1)]; + for (i = n - 1; i > 0; --i) { + E curnew; + buf[(i - 1)] = curnew = K(2.0) * I[is * (i - 1)] - cur; + cur = curnew; + } + + W = ego->td->W; + for (i = 1; i < n - i; ++i) { + E a, b, apb, amb, wa, wb; + a = buf[i]; + b = buf[n - i]; + apb = a + b; + amb = a - b; + wa = W[2*i]; + wb = W[2*i + 1]; + buf[i] = wa * amb + wb * apb; + buf[n - i] = wa * apb - wb * amb; + } + if (i == n - i) { + buf[i] = K(2.0) * buf[i] * W[2*i]; + } + + { + plan_rdft *cld = (plan_rdft *) ego->cld; + cld->apply((plan *) cld, buf, buf); + } + + W = ego->td2->W; + O[0] = W[0] * buf[0]; + for (i = 1; i < n - i; ++i) { + E a, b; + int k; + a = buf[i]; + b = buf[n - i]; + k = i + i; + O[os * (k - 1)] = W[k - 1] * (a - b); + O[os * k] = W[k] * (a + b); + } + if (i == n - i) { + O[os * (n - 1)] = W[n - 1] * buf[i]; + } + } + + X(ifree)(buf); +} + +/* like for rodft01, rodft11 is obtained from redft11 by + reversing the input and flipping the sign of every other output. */ +static void apply_ro11(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; + int iv, vl = ego->vl; + int ivs = ego->ivs, ovs = ego->ovs; + R *W; + R *buf; + E cur; + + buf = (R *) MALLOC(sizeof(R) * n, BUFFERS); + + for (iv = 0; iv < vl; ++iv, I += ivs, O += ovs) { + /* I wish that this didn't require an extra pass. */ + /* FIXME: use recursive/cascade summation for better stability? */ + buf[n - 1] = cur = K(2.0) * I[0]; + for (i = n - 1; i > 0; --i) { + E curnew; + buf[(i - 1)] = curnew = K(2.0) * I[is * (n - i)] - cur; + cur = curnew; + } + + W = ego->td->W; + for (i = 1; i < n - i; ++i) { + E a, b, apb, amb, wa, wb; + a = buf[i]; + b = buf[n - i]; + apb = a + b; + amb = a - b; + wa = W[2*i]; + wb = W[2*i + 1]; + buf[i] = wa * amb + wb * apb; + buf[n - i] = wa * apb - wb * amb; + } + if (i == n - i) { + buf[i] = K(2.0) * buf[i] * W[2*i]; + } + + { + plan_rdft *cld = (plan_rdft *) ego->cld; + cld->apply((plan *) cld, buf, buf); + } + + W = ego->td2->W; + O[0] = W[0] * buf[0]; + for (i = 1; i < n - i; ++i) { + E a, b; + int k; + a = buf[i]; + b = buf[n - i]; + k = i + i; + O[os * (k - 1)] = W[k - 1] * (b - a); + O[os * k] = W[k] * (a + b); + } + if (i == n - i) { + O[os * (n - 1)] = -W[n - 1] * buf[i]; + } + } + + X(ifree)(buf); +} + +static void awake(plan *ego_, int flg) +{ + P *ego = (P *) ego_; + static const tw_instr reodft010e_tw[] = { + { TW_COS, 0, 1 }, + { TW_SIN, 0, 1 }, + { TW_NEXT, 1, 0 } + }; + static const tw_instr reodft11e_tw[] = { + { TW_COS, 1, 1 }, + { TW_NEXT, 2, 0 } + }; + + AWAKE(ego->cld, flg); + + X(twiddle_awake)(flg, &ego->td, reodft010e_tw, 4*ego->n, 1, ego->n/2+1); + X(twiddle_awake)(flg, &ego->td2, reodft11e_tw, 8*ego->n, 1, ego->n * 2); +} + +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, "(%se-r2hc-%d%v%(%p%))", + X(rdft_kind_str)(ego->kind), ego->n, ego->vl, 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 <= 1 + && (p->kind[0] == REDFT11 || p->kind[0] == RODFT11) + ); + } + + 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; + plan *cld; + R *buf; + int n; + opcnt ops; + + static const plan_adt padt = { + X(rdft_solve), awake, print, destroy + }; + + if (!applicable(ego_, p_, plnr)) + return (plan *)0; + + p = (const problem_rdft *) p_; + + n = p->sz->dims[0].n; + buf = (R *) MALLOC(sizeof(R) * n, BUFFERS); + + cld = X(mkplan_d)(plnr, X(mkproblem_rdft_1_d)(X(mktensor_1d)(n, 1, 1), + X(mktensor_0d)(), + buf, buf, R2HC)); + X(ifree)(buf); + if (!cld) + return (plan *)0; + + pln = MKPLAN_RDFT(P, &padt, p->kind[0]==REDFT11 ? apply_re11:apply_ro11); + pln->n = n; + pln->is = p->sz->dims[0].is; + pln->os = p->sz->dims[0].os; + pln->cld = cld; + pln->td = pln->td2 = 0; + pln->kind = p->kind[0]; + + X(tensor_tornk1)(p->vecsz, &pln->vl, &pln->ivs, &pln->ovs); + + X(ops_zero)(&ops); + ops.other = 5 + (n-1) * 2 + (n-1)/2 * 12 + (1 - n % 2) * 6; + ops.add = (n - 1) * 1 + (n-1)/2 * 6; + ops.mul = 2 + (n-1) * 1 + (n-1)/2 * 6 + (1 - n % 2) * 3; + + X(ops_zero)(&pln->super.super.ops); + X(ops_madd2)(pln->vl, &ops, &pln->super.super.ops); + X(ops_madd2)(pln->vl, &cld->ops, &pln->super.super.ops); + + 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(reodft11e_r2hc_register)(planner *p) +{ + REGISTER_SOLVER(p, mksolver()); +} -- cgit v1.2.3