ref: e6586d21fad18d4cd4b72c8ff0f870db8ccbcbe6
parent: 4d0a7d0f1bc96afe8d1756f75c8b61645dd7e265
author: Jean-Marc Valin <[email protected]>
date: Fri Feb 8 05:48:15 EST 2008
Real FFT cleanup, plus some testcases
--- a/libcelt/Makefile.am
+++ b/libcelt/Makefile.am
@@ -16,8 +16,8 @@
# Sources for compilation in the library
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 \
- laplace.c mdct.c modes.c pitch.c psy.c quant_bands.c quant_pitch.c \
- rangedec.c rangeenc.c rate.c smallft.c vq.c
+ kiss_fftr.c laplace.c mdct.c modes.c pitch.c psy.c quant_bands.c \
+ quant_pitch.c rangedec.c rangeenc.c rate.c smallft.c vq.c
#noinst_HEADERS =
@@ -25,7 +25,7 @@
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 \
- _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 \
quant_bands.h quant_pitch.h rate.h smallft.h vq.h
--- a/libcelt/_kiss_fft_guts.h
+++ b/libcelt/_kiss_fft_guts.h
@@ -20,7 +20,6 @@
and defines
typedef struct { kiss_fft_scalar r; kiss_fft_scalar i; }kiss_fft_cpx; */#include "kiss_fft.h"
-//#include "math_approx.h"
#define MAXFACTORS 32
/* e.g. an fft of length 128 has 4 factors
@@ -32,6 +31,7 @@
int nfft;
int inverse;
int factors[2*MAXFACTORS];
+ int *bitrev;
kiss_fft_cpx twiddles[1];
};
--- a/libcelt/kiss_fft.c
+++ b/libcelt/kiss_fft.c
@@ -317,11 +317,11 @@
}
}
}
-
+
static
-void kf_shuffle(
- kiss_fft_cpx * Fout,
- const kiss_fft_cpx * f,
+void compute_bitrev_table(
+ int * Fout,
+ int f,
const size_t fstride,
int in_stride,
int * factors,
@@ -337,7 +337,7 @@
int j;
for (j=0;j<p;j++)
{- Fout[j] = *f;
+ Fout[j] = f;
f += fstride*in_stride;
}
} else {@@ -344,7 +344,7 @@
int 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;
Fout += m;
}
@@ -364,69 +364,21 @@
int m2
)
{- int i;
+ int i;
kiss_fft_cpx * Fout_beg=Fout;
const int p=*factors++; /* the radix */
const int m=*factors++; /* stage's fft length/p */
-#if 0
- /*printf ("fft %d %d %d %d %d %d\n", p*m, m, p, s2, fstride*in_stride, N);*/- if (m==1)
- {- /* 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) {- case 2: kf_bfly2(Fout,fstride,st,m); break;
- case 3: kf_bfly3(Fout,fstride,st,m); break;
- case 4: kf_bfly4(Fout,fstride,st,m); break;
- case 5: kf_bfly5(Fout,fstride,st,m); break;
- default: 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);
- }
+ if (m!=1)
+ 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;+ 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, ...
@@ -495,6 +447,10 @@
}
#endif
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;
}
@@ -507,11 +463,11 @@
if (fin == fout)
{ 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 {- 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);
}
}
--- /dev/null
+++ b/libcelt/kiss_fftr.c
@@ -1,0 +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);
+}
--- /dev/null
+++ b/libcelt/kiss_fftr.h
@@ -1,0 +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
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -1,18 +1,15 @@
INCLUDES = -I$(top_srcdir)/libcelt
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_LDADD = $(top_builddir)/libcelt/libcelt.la
-
ectest_SOURCES = ectest.c
-ectest_LDADD = $(top_builddir)/libcelt/libcelt.la
-
cwrs32_test_SOURCES = cwrs32-test.c
-cwrs32_test_LDADD = $(top_builddir)/libcelt/libcelt.la
-
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
--- /dev/null
+++ b/tests/dft-test.c
@@ -1,0 +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;
+}
--- /dev/null
+++ b/tests/real-fft-test.c
@@ -1,0 +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;
+}