1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
|
/*
* 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_fftr.h"
#include "_kiss_fft_guts.h"
#include <sys/times.h>
#include <time.h>
#include <unistd.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_cpx * vec2, int n)
{
int k;
double sigpow=1e-10,noisepow=1e-10,err,snr,scale=0;
#ifdef USE_SIMD
float *fv1 = (float*)vec1;
float *fv2 = (float*)vec2;
for (k=0;k<8*n;++k) {
sigpow += *fv1 * *fv1;
err = *fv1 - *fv2;
noisepow += err*err;
++fv1;
++fv2;
}
#else
for (k=0;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[k].r;
noisepow += err * err;
err = (double)vec1[k].i - (double)vec2[k].i;
noisepow += err * err;
if (vec1[k].r)
scale +=(double) vec2[k].r / (double)vec1[k].r;
}
#endif
snr = 10*log10( sigpow / noisepow );
scale /= n;
if (snr<10) {
printf( "\npoor snr, try a scaling factor %f\n" , scale );
exit(1);
}
return snr;
}
#ifndef NUMFFTS
#define NUMFFTS 10000
#endif
int main(int argc,char ** argv)
{
int nfft = 8*3*5;
double ts,tfft,trfft;
int i;
if (argc>1)
nfft = atoi(argv[1]);
kiss_fft_cpx cin[nfft];
kiss_fft_cpx cout[nfft];
kiss_fft_cpx 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(" results from kiss_fft : (%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);
printf(" results from kiss_fftr: (%f,%f), (%f,%f), (%f,%f) ...\n "
, (float)sout[0].r , (float)sout[0].i
, (float)sout[1].r , (float)sout[1].i
, (float)sout[2].r , (float)sout[2].i);
*/
printf( "nfft=%d, inverse=%d, snr=%g\n",
nfft,0, snr_compare(cout,sout,(nfft/2)+1) );
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, cout );
/* 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
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;
}
kiss_fft(kiss_fft_state,cin,cout);
kiss_fftri(kiss_fftr_state,cin,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].r = rout[i];
sout[i].i = zero;
}
printf( "nfft=%d, inverse=%d, snr=%g\n",
nfft,1, snr_compare(cout,sout,nfft/2) );
free(kiss_fft_state);
free(kiss_fftr_state);
return 0;
}
|
