Real FFT cleanup, plus some testcases

This commit is contained in:
Jean-Marc Valin 2008-02-08 10:48:15 +11:00
parent 4d0a7d0f1b
commit e6586d21fa
8 changed files with 509 additions and 80 deletions

View file

@ -16,8 +16,8 @@ lib_LTLIBRARIES = libcelt.la
# Sources for compilation in the library # Sources for compilation in the library
libcelt_la_SOURCES = bands.c bitrdec.c bitree.c bitrenc.c celt.c cwrs.c \ libcelt_la_SOURCES = bands.c bitrdec.c bitree.c bitrenc.c celt.c cwrs.c \
ecintrin.h entcode.c entdec.c entenc.c fftwrap.c header.c kiss_fft.c \ ecintrin.h entcode.c entdec.c entenc.c fftwrap.c header.c kiss_fft.c \
laplace.c mdct.c modes.c pitch.c psy.c quant_bands.c quant_pitch.c \ kiss_fftr.c laplace.c mdct.c modes.c pitch.c psy.c quant_bands.c \
rangedec.c rangeenc.c rate.c smallft.c vq.c quant_pitch.c rangedec.c rangeenc.c rate.c smallft.c vq.c
#noinst_HEADERS = #noinst_HEADERS =
@ -25,7 +25,7 @@ libcelt_la_LDFLAGS = -version-info @CELT_LT_CURRENT@:@CELT_LT_REVISION@:@CELT_LT
noinst_HEADERS = arch.h bands.h bitrdec.h bitree.h bitrenc.h cwrs.h \ noinst_HEADERS = arch.h bands.h bitrdec.h bitree.h bitrenc.h cwrs.h \
ecintrin.h entcode.h entdec.h entenc.h fftwrap.h kiss_fft.h \ ecintrin.h entcode.h entdec.h entenc.h fftwrap.h kiss_fft.h \
_kiss_fft_guts.h laplace.h mdct.h \ kiss_fftr.h _kiss_fft_guts.h laplace.h mdct.h \
mfrngcod.h modes.h os_support.h pgain_table.h pitch.h psy.h \ mfrngcod.h modes.h os_support.h pgain_table.h pitch.h psy.h \
quant_bands.h quant_pitch.h rate.h smallft.h vq.h quant_bands.h quant_pitch.h rate.h smallft.h vq.h

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@ -20,7 +20,6 @@ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
and defines and defines
typedef struct { kiss_fft_scalar r; kiss_fft_scalar i; }kiss_fft_cpx; */ typedef struct { kiss_fft_scalar r; kiss_fft_scalar i; }kiss_fft_cpx; */
#include "kiss_fft.h" #include "kiss_fft.h"
//#include "math_approx.h"
#define MAXFACTORS 32 #define MAXFACTORS 32
/* e.g. an fft of length 128 has 4 factors /* e.g. an fft of length 128 has 4 factors
@ -32,6 +31,7 @@ struct kiss_fft_state{
int nfft; int nfft;
int inverse; int inverse;
int factors[2*MAXFACTORS]; int factors[2*MAXFACTORS];
int *bitrev;
kiss_fft_cpx twiddles[1]; kiss_fft_cpx twiddles[1];
}; };

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@ -317,11 +317,11 @@ static void kf_bfly_generic(
} }
} }
} }
static static
void kf_shuffle( void compute_bitrev_table(
kiss_fft_cpx * Fout, int * Fout,
const kiss_fft_cpx * f, int f,
const size_t fstride, const size_t fstride,
int in_stride, int in_stride,
int * factors, int * factors,
@ -337,14 +337,14 @@ void kf_shuffle(
int j; int j;
for (j=0;j<p;j++) for (j=0;j<p;j++)
{ {
Fout[j] = *f; Fout[j] = f;
f += fstride*in_stride; f += fstride*in_stride;
} }
} else { } else {
int j; int j;
for (j=0;j<p;j++) for (j=0;j<p;j++)
{ {
kf_shuffle( Fout , f, fstride*p, in_stride, factors,st); compute_bitrev_table( Fout , f, fstride*p, in_stride, factors,st);
f += fstride*in_stride; f += fstride*in_stride;
Fout += m; Fout += m;
} }
@ -364,69 +364,21 @@ void kf_work(
int m2 int m2
) )
{ {
int i; int i;
kiss_fft_cpx * Fout_beg=Fout; kiss_fft_cpx * Fout_beg=Fout;
const int p=*factors++; /* the radix */ const int p=*factors++; /* the radix */
const int m=*factors++; /* stage's fft length/p */ const int m=*factors++; /* stage's fft length/p */
#if 0 /*printf ("fft %d %d %d %d %d %d %d\n", p*m, m, p, s2, fstride*in_stride, N, m2);*/
/*printf ("fft %d %d %d %d %d %d\n", p*m, m, p, s2, fstride*in_stride, N);*/ if (m!=1)
if (m==1) kf_work( Fout , f, fstride*p, in_stride, factors,st, N*p, fstride*in_stride, m);
{
/* int j;
for (j=0;j<p;j++)
{
Fout[j] = *f;
f += fstride*in_stride;
}*/
} else {
int j;
for (j=0;j<p;j++)
{
kf_work( Fout , f, fstride*p, in_stride, factors,st, N*p, fstride*in_stride, m);
f += fstride*in_stride;
Fout += m;
}
}
Fout=Fout_beg;
switch (p) { switch (p) {
case 2: kf_bfly2(Fout,fstride,st,m); break; case 2: kf_bfly2(Fout,fstride,st,m, N, m2); break;
case 3: kf_bfly3(Fout,fstride,st,m); break; case 3: for (i=0;i<N;i++){Fout=Fout_beg+i*m2; kf_bfly3(Fout,fstride,st,m);} break;
case 4: kf_bfly4(Fout,fstride,st,m); break; case 4: kf_bfly4(Fout,fstride,st,m, N, m2); break;
case 5: kf_bfly5(Fout,fstride,st,m); break; case 5: for (i=0;i<N;i++){Fout=Fout_beg+i*m2; kf_bfly5(Fout,fstride,st,m);} break;
default: kf_bfly_generic(Fout,fstride,st,m,p); break; default: for (i=0;i<N;i++){Fout=Fout_beg+i*m2; kf_bfly_generic(Fout,fstride,st,m,p);} break;
}
#else
/*printf ("fft %d %d %d %d %d %d %d\n", p*m, m, p, s2, fstride*in_stride, N, m2);*/
if (m==1)
{
/*for (i=0;i<N;i++)
{
int j;
Fout = Fout_beg+i*m2;
const kiss_fft_cpx * f2 = f+i*s2;
for (j=0;j<p;j++)
{
*Fout++ = *f2;
f2 += fstride*in_stride;
}
}*/
}else{
kf_work( Fout , f, fstride*p, in_stride, factors,st, N*p, fstride*in_stride, m);
}
switch (p) {
case 2: kf_bfly2(Fout,fstride,st,m, N, m2); break;
case 3: for (i=0;i<N;i++){Fout=Fout_beg+i*m2; kf_bfly3(Fout,fstride,st,m);} break;
case 4: kf_bfly4(Fout,fstride,st,m, N, m2); break;
case 5: for (i=0;i<N;i++){Fout=Fout_beg+i*m2; kf_bfly5(Fout,fstride,st,m);} break;
default: for (i=0;i<N;i++){Fout=Fout_beg+i*m2; kf_bfly_generic(Fout,fstride,st,m,p);} break;
} }
#endif
} }
/* facbuf is populated by p1,m1,p2,m2, ... /* facbuf is populated by p1,m1,p2,m2, ...
@ -495,6 +447,10 @@ kiss_fft_cfg kiss_fft_alloc(int nfft,int inverse_fft,void * mem,size_t * lenmem
} }
#endif #endif
kf_factor(nfft,st->factors); kf_factor(nfft,st->factors);
/* bitrev */
st->bitrev = celt_alloc(sizeof(int)*(nfft));
compute_bitrev_table(st->bitrev, 0, 1,1, st->factors,st);
} }
return st; return st;
} }
@ -507,11 +463,11 @@ void kiss_fft_stride(kiss_fft_cfg st,const kiss_fft_cpx *fin,kiss_fft_cpx *fout,
if (fin == fout) if (fin == fout)
{ {
celt_fatal("In-place FFT not supported"); celt_fatal("In-place FFT not supported");
/*CHECKBUF(tmpbuf,ntmpbuf,st->nfft);
kf_work(tmpbuf,fin,1,in_stride, st->factors,st);
SPEEX_MOVE(fout,tmpbuf,st->nfft);*/
} else { } else {
kf_shuffle( fout, fin, 1,in_stride, st->factors,st); /* Bit-reverse the input */
int i;
for (i=0;i<st->nfft;i++)
fout[i] = fin[st->bitrev[i]];
kf_work( fout, fin, 1,in_stride, st->factors,st, 1, in_stride, 1); kf_work( fout, fin, 1,in_stride, st->factors,st, 1, in_stride, 1);
} }
} }

173
libcelt/kiss_fftr.c Normal file
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@ -0,0 +1,173 @@
/*
Original version:
Copyright (c) 2003-2004, Mark Borgerding
Followed by heavy modifications:
Copyright (c) 2007-2008, Jean-Marc Valin
All rights reserved.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
* Neither the author nor the names of any contributors may be used to endorse or promote products derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "os_support.h"
#include "kiss_fftr.h"
#include "_kiss_fft_guts.h"
struct kiss_fftr_state{
kiss_fft_cfg substate;
kiss_fft_cpx * tmpbuf;
kiss_fft_cpx * super_twiddles;
#ifdef USE_SIMD
long pad;
#endif
};
kiss_fftr_cfg kiss_fftr_alloc(int nfft,int inverse_fft,void * mem,size_t * lenmem)
{
int i;
kiss_fftr_cfg st = NULL;
size_t subsize, memneeded;
if (nfft & 1) {
celt_warning("Real FFT optimization must be even.\n");
return NULL;
}
nfft >>= 1;
kiss_fft_alloc (nfft, inverse_fft, NULL, &subsize);
memneeded = sizeof(struct kiss_fftr_state) + subsize + sizeof(kiss_fft_cpx) * ( nfft * 2);
if (lenmem == NULL) {
st = (kiss_fftr_cfg) KISS_FFT_MALLOC (memneeded);
} else {
if (*lenmem >= memneeded)
st = (kiss_fftr_cfg) mem;
*lenmem = memneeded;
}
if (!st)
return NULL;
st->substate = (kiss_fft_cfg) (st + 1); /*just beyond kiss_fftr_state struct */
st->tmpbuf = (kiss_fft_cpx *) (((char *) st->substate) + subsize);
st->super_twiddles = st->tmpbuf + nfft;
kiss_fft_alloc(nfft, inverse_fft, st->substate, &subsize);
#ifdef FIXED_POINT
for (i=0;i<nfft;++i) {
celt_word32_t phase = i+(nfft>>1);
kf_cexp2(st->super_twiddles+i, DIV32(SHL32(phase,16),nfft));
}
#else
for (i=0;i<nfft;++i) {
const double pi=3.14159265358979323846264338327;
double phase = pi*(((double)i) /nfft + .5);
kf_cexp(st->super_twiddles+i, phase );
}
#endif
return st;
}
void kiss_fftr(kiss_fftr_cfg st,const kiss_fft_scalar *timedata,kiss_fft_scalar *freqdata)
{
/* input buffer timedata is stored row-wise */
int k,ncfft;
kiss_fft_cpx f2k,tdc;
celt_word32_t f1kr, f1ki, twr, twi;
if ( st->substate->inverse) {
celt_fatal("kiss fft usage error: improper alloc\n");
}
ncfft = st->substate->nfft;
/*perform the parallel fft of two real signals packed in real,imag*/
kiss_fft( st->substate , (const kiss_fft_cpx*)timedata, st->tmpbuf );
/* The real part of the DC element of the frequency spectrum in st->tmpbuf
* contains the sum of the even-numbered elements of the input time sequence
* The imag part is the sum of the odd-numbered elements
*
* The sum of tdc.r and tdc.i is the sum of the input time sequence.
* yielding DC of input time sequence
* The difference of tdc.r - tdc.i is the sum of the input (dot product) [1,-1,1,-1...
* yielding Nyquist bin of input time sequence
*/
tdc.r = st->tmpbuf[0].r;
tdc.i = st->tmpbuf[0].i;
C_FIXDIV(tdc,2);
CHECK_OVERFLOW_OP(tdc.r ,+, tdc.i);
CHECK_OVERFLOW_OP(tdc.r ,-, tdc.i);
freqdata[0] = tdc.r + tdc.i;
freqdata[2*ncfft-1] = tdc.r - tdc.i;
for ( k=1;k <= ncfft/2 ; ++k )
{
f2k.r = SHR32(SUB32(EXTEND32(st->tmpbuf[k].r), EXTEND32(st->tmpbuf[ncfft-k].r)),1);
f2k.i = PSHR32(ADD32(EXTEND32(st->tmpbuf[k].i), EXTEND32(st->tmpbuf[ncfft-k].i)),1);
f1kr = SHL32(ADD32(EXTEND32(st->tmpbuf[k].r), EXTEND32(st->tmpbuf[ncfft-k].r)),13);
f1ki = SHL32(SUB32(EXTEND32(st->tmpbuf[k].i), EXTEND32(st->tmpbuf[ncfft-k].i)),13);
twr = SHR32(ADD32(MULT16_16(f2k.r,st->super_twiddles[k].r),MULT16_16(f2k.i,st->super_twiddles[k].i)), 1);
twi = SHR32(SUB32(MULT16_16(f2k.i,st->super_twiddles[k].r),MULT16_16(f2k.r,st->super_twiddles[k].i)), 1);
#ifdef FIXED_POINT
freqdata[2*k-1] = PSHR32(f1kr + twr, 15);
freqdata[2*k] = PSHR32(f1ki + twi, 15);
freqdata[2*(ncfft-k)-1] = PSHR32(f1kr - twr, 15);
freqdata[2*(ncfft-k)] = PSHR32(twi - f1ki, 15);
#else
freqdata[2*k-1] = .5f*(f1kr + twr);
freqdata[2*k] = .5f*(f1ki + twi);
freqdata[2*(ncfft-k)-1] = .5f*(f1kr - twr);
freqdata[2*(ncfft-k)] = .5f*(twi - f1ki);
#endif
}
}
void kiss_fftri(kiss_fftr_cfg st,const kiss_fft_scalar *freqdata,kiss_fft_scalar *timedata)
{
/* input buffer timedata is stored row-wise */
int k, ncfft;
if (st->substate->inverse == 0) {
celt_fatal ("kiss fft usage error: improper alloc\n");
}
ncfft = st->substate->nfft;
st->tmpbuf[0].r = freqdata[0] + freqdata[2*ncfft-1];
st->tmpbuf[0].i = freqdata[0] - freqdata[2*ncfft-1];
for (k = 1; k <= ncfft / 2; ++k) {
kiss_fft_cpx fk, fnkc, fek, fok, tmp;
fk.r = freqdata[2*k-1];
fk.i = freqdata[2*k];
fnkc.r = freqdata[2*(ncfft - k)-1];
fnkc.i = -freqdata[2*(ncfft - k)];
C_ADD (fek, fk, fnkc);
C_SUB (tmp, fk, fnkc);
C_MUL (fok, tmp, st->super_twiddles[k]);
C_ADD (st->tmpbuf[k], fek, fok);
C_SUB (st->tmpbuf[ncfft - k], fek, fok);
#ifdef USE_SIMD
st->tmpbuf[ncfft - k].i *= _mm_set1_ps(-1.0);
#else
st->tmpbuf[ncfft - k].i *= -1;
#endif
}
kiss_fft (st->substate, st->tmpbuf, (kiss_fft_cpx *) timedata);
}

48
libcelt/kiss_fftr.h Normal file
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@ -0,0 +1,48 @@
#ifndef KISS_FTR_H
#define KISS_FTR_H
#include "kiss_fft.h"
#ifdef __cplusplus
extern "C" {
#endif
/*
Real optimized version can save about 45% cpu time vs. complex fft of a real seq.
*/
typedef struct kiss_fftr_state *kiss_fftr_cfg;
kiss_fftr_cfg kiss_fftr_alloc(int nfft,int inverse_fft,void * mem, size_t * lenmem);
/*
nfft must be even
If you don't care to allocate space, use mem = lenmem = NULL
*/
/*
input timedata has nfft scalar points
output freqdata has nfft/2+1 complex points, packed into nfft scalar points
*/
void kiss_fftr(kiss_fftr_cfg st,const kiss_fft_scalar *timedata,kiss_fft_scalar *freqdata);
void kiss_fftri(kiss_fftr_cfg st,const kiss_fft_scalar *freqdata, kiss_fft_scalar *timedata);
/*
input freqdata has nfft/2+1 complex points, packed into nfft scalar points
output timedata has nfft scalar points
*/
#define kiss_fftr_free speex_free
#ifdef __cplusplus
}
#endif
#endif

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@ -1,18 +1,15 @@
INCLUDES = -I$(top_srcdir)/libcelt INCLUDES = -I$(top_srcdir)/libcelt
METASOURCES = AUTO METASOURCES = AUTO
TESTS = type-test ectest cwrs32-test cwrs64-test TESTS = type-test ectest cwrs32-test cwrs64-test real-fft-test dft-test
bin_PROGRAMS = type-test ectest cwrs32-test cwrs64-test bin_PROGRAMS = type-test ectest cwrs32-test cwrs64-test real-fft-test dft-test
type_test_SOURCES = type-test.c type_test_SOURCES = type-test.c
type_test_LDADD = $(top_builddir)/libcelt/libcelt.la
ectest_SOURCES = ectest.c ectest_SOURCES = ectest.c
ectest_LDADD = $(top_builddir)/libcelt/libcelt.la
cwrs32_test_SOURCES = cwrs32-test.c cwrs32_test_SOURCES = cwrs32-test.c
cwrs32_test_LDADD = $(top_builddir)/libcelt/libcelt.la
cwrs64_test_SOURCES = cwrs64-test.c cwrs64_test_SOURCES = cwrs64-test.c
cwrs64_test_LDADD = $(top_builddir)/libcelt/libcelt.la real_fft_test_SOURCES = real-fft-test.c
dft_test_SOURCES = dft-test.c
LDADD = $(top_builddir)/libcelt/libcelt.la

79
tests/dft-test.c Normal file
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@ -0,0 +1,79 @@
#include <stdio.h>
#include "kiss_fft.h"
void check(kiss_fft_cpx * in,kiss_fft_cpx * out,int nfft,int isinverse)
{
int bin,k;
double errpow=0,sigpow=0;
for (bin=0;bin<nfft;++bin) {
double ansr = 0;
double ansi = 0;
double difr;
double difi;
for (k=0;k<nfft;++k) {
double phase = -2*M_PI*bin*k/nfft;
double re = cos(phase);
double im = sin(phase);
if (isinverse)
im = -im;
#ifdef FIXED_POINT
re /= nfft;
im /= nfft;
#endif
ansr += in[k].r * re - in[k].i * im;
ansi += in[k].r * im + in[k].i * re;
}
difr = ansr - out[bin].r;
difi = ansi - out[bin].i;
errpow += difr*difr + difi*difi;
sigpow += ansr*ansr+ansi*ansi;
}
printf("nfft=%d inverse=%d,snr = %f\n",nfft,isinverse,10*log10(sigpow/errpow) );
}
void test1d(int nfft,int isinverse)
{
size_t buflen = sizeof(kiss_fft_cpx)*nfft;
kiss_fft_cpx * in = (kiss_fft_cpx*)malloc(buflen);
kiss_fft_cpx * out= (kiss_fft_cpx*)malloc(buflen);
kiss_fft_cfg cfg = kiss_fft_alloc(nfft,isinverse,0,0);
int k;
for (k=0;k<nfft;++k) {
in[k].r = (rand() % 65536) - 32768;
in[k].i = (rand() % 65536) - 32768;
}
kiss_fft(cfg,in,out);
check(in,out,nfft,isinverse);
free(in);
free(out);
free(cfg);
}
int main(int argc,char ** argv)
{
if (argc>1) {
int k;
for (k=1;k<argc;++k) {
test1d(atoi(argv[k]),0);
test1d(atoi(argv[k]),1);
}
}else{
test1d(32,0);
test1d(32,1);
test1d(120,0);
test1d(120,1);
test1d(105,0);
test1d(105,1);
}
return 0;
}

176
tests/real-fft-test.c Normal file
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@ -0,0 +1,176 @@
#include "kiss_fftr.h"
#include "_kiss_fft_guts.h"
#include <sys/times.h>
#include <time.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
static double cputime(void)
{
struct tms t;
times(&t);
return (double)(t.tms_utime + t.tms_stime)/ sysconf(_SC_CLK_TCK) ;
}
static
kiss_fft_scalar rand_scalar(void)
{
#ifdef USE_SIMD
return _mm_set1_ps(rand()-RAND_MAX/2);
#else
kiss_fft_scalar s = (kiss_fft_scalar)(rand() -RAND_MAX/2);
return s/2;
#endif
}
static
double snr_compare( kiss_fft_cpx * vec1,kiss_fft_scalar * vec2, int n)
{
int k;
double sigpow=1e-10, noisepow=1e-10, err,snr;
for (k=1;k<n;++k) {
sigpow += (double)vec1[k].r * (double)vec1[k].r +
(double)vec1[k].i * (double)vec1[k].i;
err = (double)vec1[k].r - (double)vec2[2*k-1];
noisepow += err * err;
err = (double)vec1[k].i - (double)vec2[2*k];
noisepow += err * err;
}
snr = 10*log10( sigpow / noisepow );
if (snr<10) {
printf( "\npoor snr: %f\n", snr);
exit(1);
}
return snr;
}
static
double snr_compare_scal( kiss_fft_scalar * vec1,kiss_fft_scalar * vec2, int n)
{
int k;
double sigpow=1e-10, noisepow=1e-10, err,snr;
for (k=1;k<n;++k) {
sigpow += (double)vec1[k] * (double)vec1[k];
err = (double)vec1[k] - (double)vec2[k];
noisepow += err * err;
}
snr = 10*log10( sigpow / noisepow );
if (snr<10) {
printf( "\npoor snr: %f\n", snr);
exit(1);
}
return snr;
}
#define NFFT 8*3*5
#ifndef NUMFFTS
#define NUMFFTS 10000
#endif
int main(void)
{
double ts,tfft,trfft;
int i;
kiss_fft_cpx cin[NFFT];
kiss_fft_cpx cout[NFFT];
kiss_fft_scalar fin[NFFT];
kiss_fft_scalar sout[NFFT];
kiss_fft_cfg kiss_fft_state;
kiss_fftr_cfg kiss_fftr_state;
kiss_fft_scalar rin[NFFT+2];
kiss_fft_scalar rout[NFFT+2];
kiss_fft_scalar zero;
memset(&zero,0,sizeof(zero) ); // ugly way of setting short,int,float,double, or __m128 to zero
srand(time(0));
for (i=0;i<NFFT;++i) {
rin[i] = rand_scalar();
cin[i].r = rin[i];
cin[i].i = zero;
}
kiss_fft_state = kiss_fft_alloc(NFFT,0,0,0);
kiss_fftr_state = kiss_fftr_alloc(NFFT,0,0,0);
kiss_fft(kiss_fft_state,cin,cout);
kiss_fftr(kiss_fftr_state,rin,sout);
printf( "nfft=%d, inverse=%d, snr=%g\n",
NFFT,0, snr_compare(cout,sout,(NFFT/2)) );
ts = cputime();
for (i=0;i<NUMFFTS;++i) {
kiss_fft(kiss_fft_state,cin,cout);
}
tfft = cputime() - ts;
ts = cputime();
for (i=0;i<NUMFFTS;++i) {
kiss_fftr( kiss_fftr_state, rin, sout );
/* kiss_fftri(kiss_fftr_state,cout,rin); */
}
trfft = cputime() - ts;
printf("%d complex ffts took %gs, real took %gs\n",NUMFFTS,tfft,trfft);
free(kiss_fft_state);
free(kiss_fftr_state);
kiss_fft_state = kiss_fft_alloc(NFFT,1,0,0);
kiss_fftr_state = kiss_fftr_alloc(NFFT,1,0,0);
memset(cin,0,sizeof(cin));
#if 1
cin[0].r = rand_scalar();
cin[NFFT/2].r = rand_scalar();
for (i=1;i< NFFT/2;++i) {
//cin[i].r = (kiss_fft_scalar)(rand()-RAND_MAX/2);
cin[i].r = rand_scalar();
cin[i].i = rand_scalar();
}
#else
cin[0].r = 12000;
cin[3].r = 12000;
cin[NFFT/2].r = 12000;
#endif
// conjugate symmetry of real signal
for (i=1;i< NFFT/2;++i) {
cin[NFFT-i].r = cin[i].r;
cin[NFFT-i].i = - cin[i].i;
}
fin[0] = cin[0].r;
fin[NFFT-1] = cin[NFFT/2].r;
for (i=1;i< NFFT/2;++i)
{
fin[2*i-1] = cin[i].r;
fin[2*i] = cin[i].i;
}
kiss_fft(kiss_fft_state,cin,cout);
kiss_fftri(kiss_fftr_state,fin,rout);
/*
printf(" results from inverse kiss_fft : (%f,%f), (%f,%f), (%f,%f), (%f,%f), (%f,%f) ...\n "
, (float)cout[0].r , (float)cout[0].i , (float)cout[1].r , (float)cout[1].i , (float)cout[2].r , (float)cout[2].i , (float)cout[3].r , (float)cout[3].i , (float)cout[4].r , (float)cout[4].i
);
printf(" results from inverse kiss_fftr: %f,%f,%f,%f,%f ... \n"
,(float)rout[0] ,(float)rout[1] ,(float)rout[2] ,(float)rout[3] ,(float)rout[4]);
*/
for (i=0;i<NFFT;++i) {
sout[i] = cout[i].r;
}
printf( "nfft=%d, inverse=%d, snr=%g\n",
NFFT,1, snr_compare_scal(rout,sout,NFFT) );
free(kiss_fft_state);
free(kiss_fftr_state);
return 0;
}