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/* Copyright (c) 1997- Miller Puckette and others.
* For information on usage and redistribution, and for a DISCLAIMER OF ALL
* WARRANTIES, see the file, "LICENSE.txt," in this distribution. */
/* --------- Pd interface to FFTW library; imitate Mayer API ---------- */
/* changes and additions for FFTW3 by Thomas Grill */
#include "m_pd.h"
#include <fftw3.h>
int ilog2(int n);
#define MINFFT 0
#define MAXFFT 30
/* from the FFTW website:
#include <fftw3.h>
...
{
fftw_complex *in, *out;
fftw_plan p;
...
in = (fftw_complex*) fftw_malloc(sizeof(fftw_complex) * N);
out = (fftw_complex*) fftw_malloc(sizeof(fftw_complex) * N);
p = fftw_plan_dft_1d(N, in, out, FFTW_FORWARD, FFTW_ESTIMATE);
...
fftw_execute(p);
...
fftw_destroy_plan(p);
fftw_free(in); fftw_free(out);
}
FFTW_FORWARD or FFTW_BACKWARD, and indicates the direction of the transform you
are interested in. Alternatively, you can use the sign of the exponent in the
transform, -1 or +1, which corresponds to FFTW_FORWARD or FFTW_BACKWARD
respectively. The flags argument is either FFTW_MEASURE
*/
/* complex stuff */
typedef struct {
fftwf_plan plan;
fftwf_complex *in,*out;
} cfftw_info;
static cfftw_info cfftw_fwd[MAXFFT+1 - MINFFT],cfftw_bwd[MAXFFT+1 - MINFFT];
static cfftw_info *cfftw_getplan(int n,int fwd)
{
cfftw_info *info;
int logn = ilog2(n);
if (logn < MINFFT || logn > MAXFFT)
return (0);
info = (fwd?cfftw_fwd:cfftw_bwd)+(logn-MINFFT);
if (!info->plan)
{
info->in = (fftwf_complex*) fftwf_malloc(sizeof(fftwf_complex) * n);
info->out = (fftwf_complex*) fftwf_malloc(sizeof(fftwf_complex) * n);
info->plan = fftwf_plan_dft_1d(n, info->in, info->out, fwd?FFTW_FORWARD:FFTW_BACKWARD, FFTW_MEASURE);
}
return info;
}
/* real stuff */
typedef struct {
fftwf_plan plan;
float *in,*out;
} rfftw_info;
static rfftw_info rfftw_fwd[MAXFFT+1 - MINFFT],rfftw_bwd[MAXFFT+1 - MINFFT];
static rfftw_info *rfftw_getplan(int n,int fwd)
{
rfftw_info *info;
int logn = ilog2(n);
if (logn < MINFFT || logn > MAXFFT)
return (0);
info = (fwd?rfftw_fwd:rfftw_bwd)+(logn-MINFFT);
if (!info->plan)
{
info->in = (float*) fftwf_malloc(sizeof(float) * n);
info->out = (float*) fftwf_malloc(sizeof(float) * n);
info->plan = fftwf_plan_r2r_1d(n, info->in, info->out, fwd?FFTW_R2HC:FFTW_HC2R, FFTW_MEASURE);
}
return info;
}
EXTERN void mayer_fht(float *fz, int n)
{
post("FHT: not yet implemented");
}
static void mayer_do_cfft(int n, float *fz1, float *fz2, int fwd)
{
int i;
float *fz;
cfftw_info *p = cfftw_getplan(n, fwd);
if (!p)
return;
for (i = 0, fz = (float *)p->in; i < n; i++)
fz[i*2] = fz1[i], fz[i*2+1] = fz2[i];
fftwf_execute(p->plan);
for (i = 0, fz = (float *)p->out; i < n; i++)
fz1[i] = fz[i*2], fz2[i] = fz[i*2+1];
}
EXTERN void mayer_fft(int n, float *fz1, float *fz2)
{
mayer_do_cfft(n, fz1, fz2, 1);
}
EXTERN void mayer_ifft(int n, float *fz1, float *fz2)
{
mayer_do_cfft(n, fz1, fz2, 0);
}
/*
in the following the sign flips are done to
be compatible with the mayer_fft implementation,
but it's probably the mayer_fft that should be corrected...
*/
EXTERN void mayer_realfft(int n, float *fz)
{
int i;
rfftw_info *p = rfftw_getplan(n, 1);
if (!p)
return;
for (i = 0; i < n; i++)
p->in[i] = fz[i];
fftwf_execute(p->plan);
for (i = 0; i < n/2+1; i++)
fz[i] = p->out[i];
for (; i < n; i++)
fz[i] = -p->out[i];
}
EXTERN void mayer_realifft(int n, float *fz)
{
int i;
rfftw_info *p = rfftw_getplan(n, 0);
if (!p)
return;
for (i = 0; i < n/2+1; i++)
p->in[i] = fz[i];
for (; i < n; i++)
p->in[i] = -fz[i];
fftwf_execute(p->plan);
for (i = 0; i < n; i++)
fz[i] = p->out[i];
}
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