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/*
* Copyright (c) 2003-2010, Mark Borgerding. All rights reserved.
* This file is part of KISS FFT - https://github.com/mborgerding/kissfft
*
* SPDX-License-Identifier: BSD-3-Clause
* See COPYING file for more information.
*/
#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);
}
return 0;
}
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