furnace/extern/fftw/rdft/dht-r2hc.c

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/*
* 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 a DHT problem (Discrete Hartley Transform) via post-processing
of an R2HC problem. */
#include "rdft/rdft.h"
typedef struct {
solver super;
} S;
typedef struct {
plan_rdft super;
plan *cld;
INT os;
INT n;
} P;
static void apply(const plan *ego_, R *I, R *O)
{
const P *ego = (const P *) ego_;
INT os = ego->os;
INT i, n = ego->n;
{
plan_rdft *cld = (plan_rdft *) ego->cld;
cld->apply((plan *) cld, I, O);
}
for (i = 1; i < n - i; ++i) {
E a, b;
a = O[os * i];
b = O[os * (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
}
}
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, "(dht-r2hc-%D%(%p%))", ego->n, ego->cld);
}
static int applicable0(const problem *p_, const planner *plnr)
{
const problem_rdft *p = (const problem_rdft *) p_;
return (1
&& !NO_DHT_R2HCP(plnr)
&& p->sz->rnk == 1
&& p->vecsz->rnk == 0
&& p->kind[0] == DHT
);
}
static int applicable(const solver *ego, const problem *p, const planner *plnr)
{
UNUSED(ego);
return (!NO_SLOWP(plnr) && applicable0(p, plnr));
}
static plan *mkplan(const solver *ego_, const problem *p_, planner *plnr)
{
P *pln;
const problem_rdft *p;
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_;
/* NO_DHT_R2HC stops infinite loops with rdft-dht.c */
cld = X(mkplan_f_d)(plnr,
X(mkproblem_rdft_1)(p->sz, p->vecsz,
p->I, p->O, R2HC),
NO_DHT_R2HC, 0, 0);
if (!cld) return (plan *)0;
pln = MKPLAN_RDFT(P, &padt, apply);
pln->n = p->sz->dims[0].n;
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);
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(dht_r2hc_register)(planner *p)
{
REGISTER_SOLVER(p, mksolver());
}