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/*
* Copyright (c) 1997-1999 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
*
*/
/*
* planner.c -- find the optimal plan
*/
/* $Id: planner.c,v 1.2 2003-03-24 11:14:54 pj Exp $ */
#ifdef FFTW_USING_CILK
#include <cilk.h>
#include <cilk-compat.h>
#endif
#include <fftw-int.h>
#include <stdlib.h>
//#include <ports/stdio.h>
extern fftw_generic_codelet fftw_twiddle_generic;
extern fftw_generic_codelet fftwi_twiddle_generic;
extern fftw_codelet_desc *fftw_config[];
/* undocumented debugging hook */
void (*fftw_plan_hook)(fftw_plan plan) = (void (*)(fftw_plan)) 0;
static void init_test_array(fftw_complex *arr, int stride, int n)
{
int j;
for (j = 0; j < n; ++j) {
c_re(arr[stride * j]) = 0.0;
c_im(arr[stride * j]) = 0.0;
}
}
/*
* The timer keeps doubling the number of iterations
* until the program runs for more than FFTW_TIME_MIN
*/
static double fftw_measure_runtime(fftw_plan plan,
fftw_complex *in, int istride,
fftw_complex *out, int ostride)
{
fftw_time begin, end, start;
double t, tmax, tmin;
int i, iter;
int n;
int repeat;
n = plan->n;
iter = 1;
for (;;) {
tmin = 1.0E10;
tmax = -1.0E10;
init_test_array(in, istride, n);
start = fftw_get_time();
/* repeat the measurement FFTW_TIME_REPEAT times */
for (repeat = 0; repeat < FFTW_TIME_REPEAT; ++repeat) {
begin = fftw_get_time();
for (i = 0; i < iter; ++i) {
fftw(plan, 1, in, istride, 0, out, ostride, 0);
}
end = fftw_get_time();
t = fftw_time_to_sec(fftw_time_diff(end, begin));
if (t < tmin)
tmin = t;
if (t > tmax)
tmax = t;
/* do not run for too long */
t = fftw_time_to_sec(fftw_time_diff(end, start));
if (t > FFTW_TIME_LIMIT)
break;
}
if (tmin >= FFTW_TIME_MIN)
break;
iter *= 2;
}
tmin /= (double) iter;
tmax /= (double) iter;
return tmin;
}
/* auxiliary functions */
static void compute_cost(fftw_plan plan,
fftw_complex *in, int istride,
fftw_complex *out, int ostride)
{
if (plan->flags & FFTW_MEASURE)
plan->cost = fftw_measure_runtime(plan, in, istride, out, ostride);
else {
double c;
c = plan->n * fftw_estimate_node(plan->root);
plan->cost = c;
}
}
static void run_plan_hooks(fftw_plan p)
{
if (fftw_plan_hook && p) {
fftw_complete_twiddle(p->root, p->n);
fftw_plan_hook(p);
}
}
/* macrology */
#define FOR_ALL_CODELETS(p) \
fftw_codelet_desc **__q, *p; \
for (__q = &fftw_config[0]; (p = (*__q)); ++__q)
/******************************************
* Recursive planner *
******************************************/
static fftw_plan planner(fftw_plan *table, int n, fftw_direction dir, int flags,
fftw_complex *, int, fftw_complex *, int);
/*
* the planner consists of two parts: one that tries to
* use accumulated wisdom, and one that does not.
* A small driver invokes both parts in sequence
*/
/* planner with wisdom: look up the codelet suggested by the wisdom */
static fftw_plan planner_wisdom(fftw_plan *table, int n,
fftw_direction dir, int flags,
fftw_complex *in, int istride,
fftw_complex *out, int ostride)
{
fftw_plan best = (fftw_plan) 0;
fftw_plan_node *node;
int have_wisdom;
enum fftw_node_type wisdom_type;
int wisdom_signature;
/* see if we remember any wisdom for this case */
have_wisdom = fftw_wisdom_lookup(n, flags, dir, FFTW_WISDOM,
istride, ostride,
&wisdom_type, &wisdom_signature, 0);
if (!have_wisdom)
return best;
if (wisdom_type == FFTW_NOTW) {
FOR_ALL_CODELETS(p) {
if (p->dir == dir && p->type == wisdom_type) {
/* see if wisdom applies */
if (wisdom_signature == p->signature &&
p->size == n) {
node = fftw_make_node_notw(n, p);
best = fftw_make_plan(n, dir, node, flags,
p->type, p->signature);
fftw_use_plan(best);
run_plan_hooks(best);
return best;
}
}
}
}
if (wisdom_type == FFTW_TWIDDLE) {
FOR_ALL_CODELETS(p) {
if (p->dir == dir && p->type == wisdom_type) {
/* see if wisdom applies */
if (wisdom_signature == p->signature &&
p->size > 1 &&
(n % p->size) == 0) {
fftw_plan r = planner(table, n / p->size, dir, flags,
in, istride, out, ostride);
node = fftw_make_node_twiddle(n, p,
r->root, flags);
best = fftw_make_plan(n, dir, node, flags,
p->type, p->signature);
fftw_use_plan(best);
run_plan_hooks(best);
fftw_destroy_plan_internal(r);
return best;
}
}
}
}
/*
* BUG (or: TODO) Can we have generic wisdom? This is probably
* an academic question
*/
return best;
}
/*
* planner with no wisdom: try all combinations and pick
* the best
*/
static fftw_plan planner_normal(fftw_plan *table, int n, fftw_direction dir,
int flags,
fftw_complex *in, int istride,
fftw_complex *out, int ostride)
{
fftw_plan best = (fftw_plan) 0;
fftw_plan newplan;
fftw_plan_node *node;
/* see if we have any codelet that solves the problem */
{
FOR_ALL_CODELETS(p) {
if (p->dir == dir && p->type == FFTW_NOTW) {
if (p->size == n) {
node = fftw_make_node_notw(n, p);
newplan = fftw_make_plan(n, dir, node, flags,
p->type, p->signature);
fftw_use_plan(newplan);
compute_cost(newplan, in, istride, out, ostride);
run_plan_hooks(newplan);
best = fftw_pick_better(newplan, best);
}
}
}
}
/* Then, try all available twiddle codelets */
{
FOR_ALL_CODELETS(p) {
if (p->dir == dir && p->type == FFTW_TWIDDLE) {
if ((n % p->size) == 0 &&
p->size > 1 &&
(!best || n != p->size)) {
fftw_plan r = planner(table, n / p->size, dir, flags,
in, istride, out, ostride);
node = fftw_make_node_twiddle(n, p,
r->root, flags);
newplan = fftw_make_plan(n, dir, node, flags,
p->type, p->signature);
fftw_use_plan(newplan);
fftw_destroy_plan_internal(r);
compute_cost(newplan, in, istride, out, ostride);
run_plan_hooks(newplan);
best = fftw_pick_better(newplan, best);
}
}
}
}
/*
* resort to generic or rader codelets for unknown factors
*/
{
fftw_generic_codelet *codelet = (dir == FFTW_FORWARD ?
fftw_twiddle_generic :
fftwi_twiddle_generic);
int size, prev_size = 0, remaining_factors = n;
fftw_plan r;
while (remaining_factors > 1) {
size = fftw_factor(remaining_factors);
remaining_factors /= size;
/* don't try the same factor more than once */
if (size == prev_size)
continue;
prev_size = size;
/* Look for codelets corresponding to this factor. */
{
FOR_ALL_CODELETS(p) {
if (p->dir == dir && p->type == FFTW_TWIDDLE
&& p->size == size) {
size = 0;
break;
}
}
}
/*
* only try a generic/rader codelet if there were no
* twiddle codelets for this factor
*/
if (!size)
continue;
r = planner(table, n / size, dir, flags,
in, istride, out, ostride);
/* Try Rader codelet: */
node = fftw_make_node_rader(n, size, dir, r->root, flags);
newplan = fftw_make_plan(n, dir, node, flags, FFTW_RADER, 0);
fftw_use_plan(newplan);
compute_cost(newplan, in, istride, out, ostride);
run_plan_hooks(newplan);
best = fftw_pick_better(newplan, best);
if (size < 100) { /*
* only try generic for small
* sizes
*/
/* Try generic codelet: */
node = fftw_make_node_generic(n, size, codelet,
r->root, flags);
newplan = fftw_make_plan(n, dir, node, flags,
FFTW_GENERIC, 0);
fftw_use_plan(newplan);
compute_cost(newplan, in, istride, out, ostride);
run_plan_hooks(newplan);
best = fftw_pick_better(newplan, best);
}
fftw_destroy_plan_internal(r);
}
}
if (!best)
fftw_die("bug in planner");
return best;
}
static fftw_plan planner(fftw_plan *table, int n, fftw_direction dir,
int flags,
fftw_complex *in, int istride,
fftw_complex *out, int ostride)
{
fftw_plan best = (fftw_plan) 0;
/* see if plan has already been computed */
best = fftw_lookup(table, n, flags);
if (best) {
fftw_use_plan(best);
return best;
}
/* try a wise plan */
best = planner_wisdom(table, n, dir, flags,
in, istride, out, ostride);
if (!best) {
/* No wisdom. Plan normally. */
best = planner_normal(table, n, dir, flags,
in, istride, out, ostride);
}
if (best) {
fftw_insert(table, best, n);
/* remember the wisdom */
fftw_wisdom_add(n, flags, dir, FFTW_WISDOM, istride, ostride,
best->wisdom_type,
best->wisdom_signature);
}
return best;
}
fftw_plan fftw_create_plan_specific(int n, fftw_direction dir, int flags,
fftw_complex *in, int istride,
fftw_complex *out, int ostride)
{
fftw_plan table;
fftw_plan p1;
/* validate parameters */
if (n <= 0)
return (fftw_plan) 0;
if ((dir != FFTW_FORWARD) && (dir != FFTW_BACKWARD))
return (fftw_plan) 0;
fftw_make_empty_table(&table);
p1 = planner(&table, n, dir, flags,
in, istride, out, ostride);
fftw_destroy_table(&table);
fftw_complete_twiddle(p1->root, n);
return p1;
}
fftw_plan fftw_create_plan(int n, fftw_direction dir, int flags)
{
fftw_complex *tmp_in, *tmp_out;
fftw_plan p;
if (flags & FFTW_MEASURE) {
tmp_in = (fftw_complex *) fftw_malloc(2 * n * sizeof(fftw_complex));
if (!tmp_in)
return 0;
tmp_out = tmp_in + n;
p = fftw_create_plan_specific(n, dir, flags,
tmp_in, 1, tmp_out, 1);
fftw_free(tmp_in);
} else
p = fftw_create_plan_specific(n, dir, flags,
(fftw_complex *) 0, 1, (fftw_complex *) 0, 1);
return p;
}
void fftw_destroy_plan(fftw_plan plan)
{
fftw_destroy_plan_internal(plan);
}