diff options
author | scuri <scuri> | 2008-10-17 06:10:15 +0000 |
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committer | scuri <scuri> | 2008-10-17 06:10:15 +0000 |
commit | 5a422aba704c375a307a902bafe658342e209906 (patch) | |
tree | 5005011e086bb863d8fb587ad3319bbec59b2447 /src/fftw3/dft/rader.c |
First commit - moving from LuaForge to SourceForge
Diffstat (limited to 'src/fftw3/dft/rader.c')
-rw-r--r-- | src/fftw3/dft/rader.c | 491 |
1 files changed, 491 insertions, 0 deletions
diff --git a/src/fftw3/dft/rader.c b/src/fftw3/dft/rader.c new file mode 100644 index 0000000..f31f370 --- /dev/null +++ b/src/fftw3/dft/rader.c @@ -0,0 +1,491 @@ +/* + * 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 + * + */ + +#include "dft.h" + +/* + * Compute transforms of prime sizes using Rader's trick: turn them + * into convolutions of size n - 1, which you then perform via a pair + * of FFTs. This file contains both nontwiddle (direct) and + * twiddle (DIT Cooley-Tukey) solvers. + */ + +typedef struct { + solver super; +} S; + +typedef struct { + plan_dft super; + + plan *cld1, *cld2; + R *omega; + int n, g, ginv; + int is, os; + plan *cld_omega; +} P; + +typedef struct { + P super; + plan *cld; + R *W; + int os; + int m; +} P_dit; + + +static rader_tl *twiddles = 0; + +/***************************************************************************/ + +/* Below, we extensively use the identity that fft(x*)* = ifft(x) in + order to share data between forward and backward transforms and to + obviate the necessity of having separate forward and backward + plans. (Although we often compute separate plans these days anyway + due to the differing strides, etcetera.) + + Of course, since the new FFTW gives us separate pointers to + the real and imaginary parts, we could have instead used the + fft(r,i) = ifft(i,r) form of this identity, but it was easier to + reuse the code from our old version. */ + +static void apply_aux(int r, int ginv, plan *cld1,plan *cld2, const R *omega, + R *buf, R r0, R i0, R *ro, R *io, int os) +{ + int gpower, k; + + /* compute DFT of buf, storing in output (except DC): */ + { + plan_dft *cld = (plan_dft *) cld1; + cld->apply(cld1, buf, buf+1, ro+os, io+os); + } + + /* set output DC component: */ + ro[0] = r0 + ro[os]; + io[0] = i0 + io[os]; + + /* now, multiply by omega: */ + for (k = 0; k < r - 1; ++k) { + E rB, iB, rW, iW; + rW = omega[2*k]; + iW = omega[2*k+1]; + rB = ro[(k+1)*os]; + iB = io[(k+1)*os]; + ro[(k+1)*os] = rW * rB - iW * iB; + io[(k+1)*os] = -(rW * iB + iW * rB); + } + + /* this will add input[0] to all of the outputs after the ifft */ + ro[os] += r0; + io[os] -= i0; + + /* inverse FFT: */ + { + plan_dft *cld = (plan_dft *) cld2; + cld->apply(cld2, ro+os, io+os, buf, buf+1); + } + + /* finally, do inverse permutation to unshuffle the output: */ + gpower = 1; + for (k = 0; k < r - 1; ++k, gpower = MULMOD(gpower, ginv, r)) { + ro[gpower * os] = buf[2*k]; + io[gpower * os] = -buf[2*k+1]; + } + A(gpower == 1); +} + +static void apply(const plan *ego_, R *ri, R *ii, R *ro, R *io) +{ + const P *ego = (const P *) ego_; + int is; + int k, gpower, g, r; + R *buf; + + r = ego->n; is = ego->is; g = ego->g; + buf = (R *) MALLOC(sizeof(R) * (r - 1) * 2, BUFFERS); + + /* First, permute the input, storing in buf: */ + for (gpower = 1, k = 0; k < r - 1; ++k, gpower = MULMOD(gpower, g, r)) { + R rA, iA; + rA = ri[gpower * is]; + iA = ii[gpower * is]; + buf[2*k] = rA; buf[2*k + 1] = iA; + } + /* gpower == g^(r-1) mod r == 1 */; + + apply_aux(r, ego->ginv, ego->cld1, ego->cld2, ego->omega, + buf, ri[0], ii[0], ro, io, ego->os); + + X(ifree)(buf); +} + +static void apply_dit(const plan *ego_, R *ri, R *ii, R *ro, R *io) +{ + const P_dit *ego_dit = (const P_dit *) ego_; + const P *ego; + plan *cld1, *cld2; + int os, osm; + int j, k, gpower, g, ginv, r, m; + R *buf; + const R *omega, *W; + + { + plan *cld0 = ego_dit->cld; + plan_dft *cld = (plan_dft *) cld0; + cld->apply(cld0, ri, ii, ro, io); + } + + ego = (const P *) ego_; + cld1 = ego->cld1; + cld2 = ego->cld2; + r = ego->n; + m = ego_dit->m; + g = ego->g; + ginv = ego->ginv; + omega = ego->omega; + W = ego_dit->W; + os = ego_dit->os; + osm = ego->os; + gpower = 1; + + buf = (R *) MALLOC(sizeof(R) * (r - 1) * 2, BUFFERS); + + for (j = 0; j < m; ++j, ro += os, io += os, W += 2*(r - 1)) { + /* First, permute the input and multiply by W, storing in buf: */ + A(gpower == 1); + for (k = 0; k < r - 1; ++k, gpower = MULMOD(gpower, g, r)) { + E rA, iA, rW, iW; + rA = ro[gpower * osm]; + iA = io[gpower * osm]; + rW = W[2*k]; + iW = W[2*k+1]; + buf[2*k] = rW * rA - iW * iA; + buf[2*k + 1] = rW * iA + iW * rA; + } + /* gpower == g^(r-1) mod r == 1 */; + + apply_aux(r, ginv, cld1, cld2, omega, + buf, ro[0], io[0], ro, io, osm); + } + + X(ifree)(buf); +} + +static R *mktwiddle(int m, int r, int g) +{ + int i, j, gpower; + int n = r * m; + R *W; + + if ((W = X(rader_tl_find)(m, r, g, twiddles))) + return W; + + W = (R *)MALLOC(sizeof(R) * (r - 1) * m * 2, TWIDDLES); + for (i = 0; i < m; ++i) { + for (gpower = 1, j = 0; j < r - 1; + ++j, gpower = MULMOD(gpower, g, r)) { + int k = i * (r - 1) + j; + W[2*k] = X(cos2pi)(i * gpower, n); + W[2*k+1] = FFT_SIGN * X(sin2pi)(i * gpower, n); + } + A(gpower == 1); + } + + X(rader_tl_insert)(m, r, g, W, &twiddles); + return W; +} + +static void free_twiddle(R *twiddle) +{ + X(rader_tl_delete)(twiddle, &twiddles); +} + +/***************************************************************************/ + +static void awake(plan *ego_, int flg) +{ + P *ego = (P *) ego_; + + AWAKE(ego->cld1, flg); + AWAKE(ego->cld2, flg); + + if (flg) { + if (!ego->omega) + ego->omega = + X(dft_rader_mkomega)(ego->cld_omega, ego->n, ego->ginv); + } else { + X(dft_rader_free_omega)(&ego->omega); + } +} + +static void awake_dit(plan *ego_, int flg) +{ + P_dit *ego = (P_dit *) ego_; + + AWAKE(ego->cld, flg); + if (flg) + ego->W = mktwiddle(ego->m, ego->super.n, ego->super.g); + else { + free_twiddle(ego->W); + ego->W = 0; + } + + awake(ego_, flg); +} + +static void destroy(plan *ego_) +{ + P *ego = (P *) ego_; + X(plan_destroy_internal)(ego->cld_omega); + X(plan_destroy_internal)(ego->cld2); + X(plan_destroy_internal)(ego->cld1); +} + +static void destroy_dit(plan *ego_) +{ + P_dit *ego = (P_dit *) ego_; + X(plan_destroy_internal)(ego->cld); + destroy(ego_); +} + +static void print_aux(const char *name, const P *ego, printer *p) +{ + p->print(p, "(%s-%d%ois=%oos=%(%p%)", + name, ego->n, ego->is, ego->os, ego->cld1); + if (ego->cld2 != ego->cld1) + p->print(p, "%(%p%)", ego->cld2); + if (ego->cld_omega != ego->cld1 && ego->cld_omega != ego->cld2) + p->print(p, "%(%p%)", ego->cld_omega); +} + +static void print(const plan *ego_, printer *p) +{ + print_aux("dft-rader", (const P *) ego_, p); + p->putchr(p, ')'); +} + +static void print_dit(const plan *ego_, printer *p) +{ + const P_dit *ego_dit = (const P_dit *) ego_; + + print_aux("dft-rader-dit", (const P *) ego_, p); + p->print(p, "%(%p%))", ego_dit->cld); +} + +static int applicable0(const solver *ego_, const problem *p_) +{ + UNUSED(ego_); + if (DFTP(p_)) { + const problem_dft *p = (const problem_dft *) p_; + return (1 + && p->sz->rnk == 1 + && p->vecsz->rnk == 0 + && X(is_prime)(p->sz->dims[0].n) + ); + } + + return 0; +} + +static int applicable0_dit(const solver *ego_, const problem *p_) +{ + UNUSED(ego_); + if (DFTP(p_)) { + const problem_dft *p = (const problem_dft *) p_; + return (1 + && p->sz->rnk == 1 + && p->vecsz->rnk == 0 + && p->sz->dims[0].n > 1 + ); + } + + return 0; +} + +static int applicable(const solver *ego_, const problem *p_, + const planner *plnr) +{ + return (!NO_UGLYP(plnr) && applicable0(ego_, p_)); +} + +static int applicable_dit(const solver *ego_, const problem *p_, + const planner *plnr) +{ + return (!NO_UGLYP(plnr) && applicable0_dit(ego_, p_)); +} + +static int mkP(P *pln, int n, int is, int os, R *ro, R *io, + planner *plnr) +{ + plan *cld1 = (plan *) 0; + plan *cld2 = (plan *) 0; + plan *cld_omega = (plan *) 0; + R *buf = (R *) 0; + + /* initial allocation for the purpose of planning */ + buf = (R *) MALLOC(sizeof(R) * (n - 1) * 2, BUFFERS); + + cld1 = X(mkplan_d)(plnr, + X(mkproblem_dft_d)(X(mktensor_1d)(n - 1, 2, os), + X(mktensor_1d)(1, 0, 0), + buf, buf + 1, ro + os, io + os)); + if (!cld1) goto nada; + + cld2 = X(mkplan_d)(plnr, + X(mkproblem_dft_d)(X(mktensor_1d)(n - 1, os, 2), + X(mktensor_1d)(1, 0, 0), + ro + os, io + os, buf, buf + 1)); + + if (!cld2) goto nada; + + /* plan for omega array */ + plnr->planner_flags |= ESTIMATE; + cld_omega = X(mkplan_d)(plnr, + X(mkproblem_dft_d)(X(mktensor_1d)(n - 1, 2, 2), + X(mktensor_1d)(1, 0, 0), + buf, buf + 1, buf, buf + 1)); + if (!cld_omega) goto nada; + + /* deallocate buffers; let awake() or apply() allocate them for real */ + X(ifree)(buf); + buf = 0; + + pln->cld1 = cld1; + pln->cld2 = cld2; + pln->cld_omega = cld_omega; + pln->omega = 0; + pln->n = n; + pln->is = is; + pln->os = os; + pln->g = X(find_generator)(n); + pln->ginv = X(power_mod)(pln->g, n - 2, n); + A(MULMOD(pln->g, pln->ginv, n) == 1); + + X(ops_add)(&cld1->ops, &cld2->ops, &pln->super.super.ops); + pln->super.super.ops.other += (n - 1) * (4 * 2 + 6) + 6; + pln->super.super.ops.add += (n - 1) * 2 + 4; + pln->super.super.ops.mul += (n - 1) * 4; + + return 1; + + nada: + X(ifree0)(buf); + X(plan_destroy_internal)(cld_omega); + X(plan_destroy_internal)(cld2); + X(plan_destroy_internal)(cld1); + return 0; +} + +static plan *mkplan(const solver *ego, const problem *p_, planner *plnr) +{ + const problem_dft *p = (const problem_dft *) p_; + P *pln; + int n; + int is, os; + + static const plan_adt padt = { + X(dft_solve), awake, print, destroy + }; + + if (!applicable(ego, p_, plnr)) + return (plan *) 0; + + n = p->sz->dims[0].n; + is = p->sz->dims[0].is; + os = p->sz->dims[0].os; + + pln = MKPLAN_DFT(P, &padt, apply); + if (!mkP(pln, n, is, os, p->ro, p->io, plnr)) { + X(ifree)(pln); + return (plan *) 0; + } + return &(pln->super.super); +} + +static plan *mkplan_dit(const solver *ego, const problem *p_, planner *plnr) +{ + const problem_dft *p = (const problem_dft *) p_; + P_dit *pln = 0; + int n, r, m; + int is, os; + plan *cld = (plan *) 0; + + static const plan_adt padt = { + X(dft_solve), awake_dit, print_dit, destroy_dit + }; + + if (!applicable_dit(ego, p_, plnr)) + goto nada; + + n = p->sz->dims[0].n; + is = p->sz->dims[0].is; + os = p->sz->dims[0].os; + + r = X(first_divisor)(n); + m = n / r; + + cld = X(mkplan_d)(plnr, + X(mkproblem_dft_d)(X(mktensor_1d)(m, r * is, os), + X(mktensor_1d)(r, is, m * os), + p->ri, p->ii, p->ro, p->io)); + if (!cld) goto nada; + + pln = MKPLAN_DFT(P_dit, &padt, apply_dit); + if (!mkP(&pln->super, r, os*m, os*m, p->ro, p->io, plnr)) + goto nada; + + pln->os = os; + pln->m = m; + pln->cld = cld; + pln->W = 0; + + pln->super.super.super.ops.add += 2 * (r-1); + pln->super.super.super.ops.mul += 4 * (r-1); + X(ops_madd)(m, &pln->super.super.super.ops, &cld->ops, + &pln->super.super.super.ops); + + return &(pln->super.super.super); + + nada: + X(plan_destroy_internal)(cld); + X(ifree0)(pln); + return (plan *) 0; +} + +/* constructors */ + +static solver *mksolver(void) +{ + static const solver_adt sadt = { mkplan }; + S *slv = MKSOLVER(S, &sadt); + return &(slv->super); +} + +static solver *mksolver_dit(void) +{ + static const solver_adt sadt = { mkplan_dit }; + S *slv = MKSOLVER(S, &sadt); + return &(slv->super); +} + +void X(dft_rader_register)(planner *p) +{ + REGISTER_SOLVER(p, mksolver()); + REGISTER_SOLVER(p, mksolver_dit()); +} |