/*
* 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
*
*/
/* express a hc2hc problem in terms of rdft + multiplication by
twiddle factors */
#include "rdft/hc2hc.h"
typedef hc2hc_solver S;
typedef struct {
plan_hc2hc super;
INT r, m, s, vl, vs, mstart1, mcount1;
plan *cld0;
plan *cld;
twid *td;
} P;
/**************************************************************/
static void mktwiddle(P *ego, enum wakefulness wakefulness)
{
static const tw_instr tw[] = { { TW_HALF, 0, 0 }, { TW_NEXT, 1, 0 } };
/* note that R and M are swapped, to allow for sequential
access both to data and twiddles */
X(twiddle_awake)(wakefulness, &ego->td, tw,
ego->r * ego->m, ego->m, ego->r);
}
static void bytwiddle(const P *ego, R *IO, R sign)
{
INT i, j, k;
INT r = ego->r, m = ego->m, s = ego->s, vl = ego->vl, vs = ego->vs;
INT ms = m * s;
INT mstart1 = ego->mstart1, mcount1 = ego->mcount1;
INT wrem = 2 * ((m-1)/2 - mcount1);
for (i = 0; i < vl; ++i, IO += vs) {
const R *W = ego->td->W;
A(m % 2 == 1);
for (k = 1, W += (m - 1) + 2*(mstart1-1); k < r; ++k) {
/* pr := IO + (j + mstart1) * s + k * ms */
R *pr = IO + mstart1 * s + k * ms;
/* pi := IO + (m - j - mstart1) * s + k * ms */
R *pi = IO - mstart1 * s + (k + 1) * ms;
for (j = 0; j < mcount1; ++j, pr += s, pi -= s) {
E xr = *pr;
E xi = *pi;
E wr = W[0];
E wi = sign * W[1];
*pr = xr * wr - xi * wi;
*pi = xi * wr + xr * wi;
W += 2;
}
W += wrem;
}
}
}
static void swapri(R *IO, INT r, INT m, INT s, INT jstart, INT jend)
{
INT k;
INT ms = m * s;
INT js = jstart * s;
for (k = 0; k + k < r; ++k) {
/* pr := IO + (m - j) * s + k * ms */
R *pr = IO + (k + 1) * ms - js;
/* pi := IO + (m - j) * s + (r - 1 - k) * ms */
R *pi = IO + (r - k) * ms - js;
INT j;
for (j = jstart; j < jend; j += 1, pr -= s, pi -= s) {
R t = *pr;
*pr = *pi;
*pi = t;
}
}
}
static void reorder_dit(const P *ego, R *IO)
{
INT i, k;
INT r = ego->r, m = ego->m, s = ego->s, vl = ego->vl, vs = ego->vs;
INT ms = m * s;
INT mstart1 = ego->mstart1, mend1 = mstart1 + ego->mcount1;
for (i = 0; i < vl; ++i, IO += vs) {
for (k = 1; k + k < r; ++k) {
R *p0 = IO + k * ms;
R *p1 = IO + (r - k) * ms;
INT j;
for (j = mstart1; j < mend1; ++j) {
E rp, ip, im, rm;
rp = p0[j * s];
im = p1[ms - j * s];
rm = p1[j * s];
ip = p0[ms - j * s];
p0[j * s] = rp - im;
p1[ms - j * s] = rp + im;
p1[j * s] = rm - ip;
p0[ms - j * s] = ip + rm;
}
}
swapri(IO, r, m, s, mstart1, mend1);
}
}
static void reorder_dif(const P *ego, R *IO)
{
INT i, k;
INT r = ego->r, m = ego->m, s = ego->s, vl = ego->vl, vs = ego->vs;
INT ms = m * s;
INT mstart1 = ego->mstart1, mend1 = mstart1 + ego->mcount1;
for (i = 0; i < vl; ++i, IO += vs) {
swapri(IO, r, m, s, mstart1, mend1);
for (k = 1; k + k < r; ++k) {
R *p0 = IO + k * ms;
R *p1 = IO + (r - k) * ms;
const R half = K(0.5);
INT j;
for (j = mstart1; j < mend1; ++j) {
E rp, ip, im, rm;
rp = half * p0[j * s];
im = half * p1[ms - j * s];
rm = half * p1[j * s];
ip = half * p0[ms - j * s];
p0[j * s] = rp + im;
p1[ms - j * s] = im - rp;
p1[j * s] = rm + ip;
p0[ms - j * s] = ip - rm;
}
}
}
}
static int applicable(rdft_kind kind, INT r, INT m, const planner *plnr)
{
return (1
&& (kind == R2HC || kind == HC2R)
&& (m % 2)
&& (r % 2)
&& !NO_SLOWP(plnr)
);
}
/**************************************************************/
static void apply_dit(const plan *ego_, R *IO)
{
const P *ego = (const P *) ego_;
INT start;
plan_rdft *cld, *cld0;
bytwiddle(ego, IO, K(-1.0));
cld0 = (plan_rdft *) ego->cld0;
cld0->apply(ego->cld0, IO, IO);
start = ego->mstart1 * ego->s;
cld = (plan_rdft *) ego->cld;
cld->apply(ego->cld, IO + start, IO + start);
reorder_dit(ego, IO);
}
static void apply_dif(const plan *ego_, R *IO)
{
const P *ego = (const P *) ego_;
INT start;
plan_rdft *cld, *cld0;
reorder_dif(ego, IO);
cld0 = (plan_rdft *) ego->cld0;
cld0->apply(ego->cld0, IO, IO);
start = ego->mstart1 * ego->s;
cld = (plan_rdft *) ego->cld;
cld->apply(ego->cld, IO + start, IO + start);
bytwiddle(ego, IO, K(1.0));
}
static void awake(plan *ego_, enum wakefulness wakefulness)
{
P *ego = (P *) ego_;
X(plan_awake)(ego->cld0, wakefulness);
X(plan_awake)(ego->cld, wakefulness);
mktwiddle(ego, wakefulness);
}
static void destroy(plan *ego_)
{
P *ego = (P *) ego_;
X(plan_destroy_internal)(ego->cld);
X(plan_destroy_internal)(ego->cld0);
}
static void print(const plan *ego_, printer *p)
{
const P *ego = (const P *) ego_;
p->print(p, "(hc2hc-generic-%s-%D-%D%v%(%p%)%(%p%))",
ego->super.apply == apply_dit ? "dit" : "dif",
ego->r, ego->m, ego->vl, ego->cld0, ego->cld);
}
static plan *mkcldw(const hc2hc_solver *ego_,
rdft_kind kind, INT r, INT m, INT s, INT vl, INT vs,
INT mstart, INT mcount,
R *IO, planner *plnr)
{
P *pln;
plan *cld0 = 0, *cld = 0;
INT mstart1, mcount1, mstride;
static const plan_adt padt = {
0, awake, print, destroy
};
UNUSED(ego_);
A(mstart >= 0 && mcount > 0 && mstart + mcount <= (m+2)/2);
if (!applicable(kind, r, m, plnr))
return (plan *)0;
A(m % 2);
mstart1 = mstart + (mstart == 0);
mcount1 = mcount - (mstart == 0);
mstride = m - (mstart + mcount - 1) - mstart1;
/* 0th (DC) transform (vl of these), if mstart == 0 */
cld0 = X(mkplan_d)(plnr,
X(mkproblem_rdft_1_d)(
mstart == 0 ? X(mktensor_1d)(r, m * s, m * s)
: X(mktensor_0d)(),
X(mktensor_1d)(vl, vs, vs),
IO, IO, kind)
);
if (!cld0) goto nada;
/* twiddle transforms: there are 2 x mcount1 x vl of these
(where 2 corresponds to the real and imaginary parts) ...
the 2 x mcount1 loops are combined if mstart=0 and mcount=(m+2)/2. */
cld = X(mkplan_d)(plnr,
X(mkproblem_rdft_1_d)(
X(mktensor_1d)(r, m * s, m * s),
X(mktensor_3d)(2, mstride * s, mstride * s,
mcount1, s, s,
vl, vs, vs),
IO + s * mstart1, IO + s * mstart1, kind)
);
if (!cld) goto nada;
pln = MKPLAN_HC2HC(P, &padt, (kind == R2HC) ? apply_dit : apply_dif);
pln->cld = cld;
pln->cld0 = cld0;
pln->r = r;
pln->m = m;
pln->s = s;
pln->vl = vl;
pln->vs = vs;
pln->td = 0;
pln->mstart1 = mstart1;
pln->mcount1 = mcount1;
{
double n0 = 0.5 * (r - 1) * (2 * mcount1) * vl;
pln->super.super.ops = cld->ops;
pln->super.super.ops.mul += (kind == R2HC ? 5.0 : 7.0) * n0;
pln->super.super.ops.add += 4.0 * n0;
pln->super.super.ops.other += 11.0 * n0;
}
return &(pln->super.super);
nada:
X(plan_destroy_internal)(cld);
X(plan_destroy_internal)(cld0);
return (plan *) 0;
}
static void regsolver(planner *plnr, INT r)
{
S *slv = (S *)X(mksolver_hc2hc)(sizeof(S), r, mkcldw);
REGISTER_SOLVER(plnr, &(slv->super));
if (X(mksolver_hc2hc_hook)) {
slv = (S *)X(mksolver_hc2hc_hook)(sizeof(S), r, mkcldw);
REGISTER_SOLVER(plnr, &(slv->super));
}
}
void X(hc2hc_generic_register)(planner *p)
{
regsolver(p, 0);
}