170 lines
4.2 KiB
C
170 lines
4.2 KiB
C
/*
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* Copyright (c) 2003, 2007-14 Matteo Frigo
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* Copyright (c) 2003, 2007-14 Massachusetts Institute of Technology
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*/
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#include "dft/dft.h"
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typedef struct {
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solver super;
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} S;
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typedef struct {
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plan_dft super;
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twid *td;
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INT n, is, os;
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} P;
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static void cdot(INT n, const E *x, const R *w,
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R *or0, R *oi0, R *or1, R *oi1)
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{
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INT i;
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E rr = x[0], ri = 0, ir = x[1], ii = 0;
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x += 2;
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for (i = 1; i + i < n; ++i) {
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rr += x[0] * w[0];
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ir += x[1] * w[0];
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ri += x[2] * w[1];
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ii += x[3] * w[1];
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x += 4; w += 2;
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}
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*or0 = rr + ii;
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*oi0 = ir - ri;
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*or1 = rr - ii;
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*oi1 = ir + ri;
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}
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static void hartley(INT n, const R *xr, const R *xi, INT xs, E *o,
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R *pr, R *pi)
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{
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INT i;
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E sr, si;
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o[0] = sr = xr[0]; o[1] = si = xi[0]; o += 2;
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for (i = 1; i + i < n; ++i) {
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sr += (o[0] = xr[i * xs] + xr[(n - i) * xs]);
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si += (o[1] = xi[i * xs] + xi[(n - i) * xs]);
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o[2] = xr[i * xs] - xr[(n - i) * xs];
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o[3] = xi[i * xs] - xi[(n - i) * xs];
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o += 4;
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}
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*pr = sr;
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*pi = si;
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}
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static void apply(const plan *ego_, R *ri, R *ii, R *ro, R *io)
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{
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const P *ego = (const P *) ego_;
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INT i;
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INT n = ego->n, is = ego->is, os = ego->os;
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const R *W = ego->td->W;
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E *buf;
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size_t bufsz = n * 2 * sizeof(E);
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BUF_ALLOC(E *, buf, bufsz);
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hartley(n, ri, ii, is, buf, ro, io);
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for (i = 1; i + i < n; ++i) {
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cdot(n, buf, W,
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ro + i * os, io + i * os,
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ro + (n - i) * os, io + (n - i) * os);
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W += n - 1;
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}
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BUF_FREE(buf, bufsz);
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}
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static void awake(plan *ego_, enum wakefulness wakefulness)
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{
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P *ego = (P *) ego_;
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static const tw_instr half_tw[] = {
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{ TW_HALF, 1, 0 },
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{ TW_NEXT, 1, 0 }
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};
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X(twiddle_awake)(wakefulness, &ego->td, half_tw, ego->n, ego->n,
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(ego->n - 1) / 2);
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}
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static void print(const plan *ego_, printer *p)
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{
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const P *ego = (const P *) ego_;
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p->print(p, "(dft-generic-%D)", ego->n);
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}
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static int applicable(const solver *ego, const problem *p_,
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const planner *plnr)
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{
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const problem_dft *p = (const problem_dft *) p_;
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UNUSED(ego);
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return (1
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&& p->sz->rnk == 1
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&& p->vecsz->rnk == 0
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&& (p->sz->dims[0].n % 2) == 1
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&& CIMPLIES(NO_LARGE_GENERICP(plnr), p->sz->dims[0].n < GENERIC_MIN_BAD)
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&& CIMPLIES(NO_SLOWP(plnr), p->sz->dims[0].n > GENERIC_MAX_SLOW)
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&& X(is_prime)(p->sz->dims[0].n)
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);
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}
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static plan *mkplan(const solver *ego, const problem *p_, planner *plnr)
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{
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const problem_dft *p;
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P *pln;
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INT n;
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static const plan_adt padt = {
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X(dft_solve), awake, print, X(plan_null_destroy)
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};
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if (!applicable(ego, p_, plnr))
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return (plan *)0;
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pln = MKPLAN_DFT(P, &padt, apply);
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p = (const problem_dft *) p_;
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pln->n = n = p->sz->dims[0].n;
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pln->is = p->sz->dims[0].is;
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pln->os = p->sz->dims[0].os;
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pln->td = 0;
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pln->super.super.ops.add = (n-1) * 5;
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pln->super.super.ops.mul = 0;
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pln->super.super.ops.fma = (n-1) * (n-1) ;
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#if 0 /* these are nice pipelined sequential loads and should cost nothing */
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pln->super.super.ops.other = (n-1)*(4 + 1 + 2 * (n-1)); /* approximate */
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#endif
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return &(pln->super.super);
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}
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static solver *mksolver(void)
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{
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static const solver_adt sadt = { PROBLEM_DFT, mkplan, 0 };
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S *slv = MKSOLVER(S, &sadt);
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return &(slv->super);
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}
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void X(dft_generic_register)(planner *p)
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{
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REGISTER_SOLVER(p, mksolver());
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}
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