Libav
lfg.c
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1 /*
2  * This file is part of Libav.
3  *
4  * Libav is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
9  * Libav is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public
15  * License along with Libav; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17  */
18 
19 #include "libavutil/log.h"
20 #include "libavutil/timer.h"
21 #include "libavutil/lfg.h"
22 
23 int main(void)
24 {
25  int x = 0;
26  int i, j;
27  AVLFG state;
28 
29  av_lfg_init(&state, 0xdeadbeef);
30  for (j = 0; j < 10000; j++) {
32  for (i = 0; i < 624; i++)
33  x += av_lfg_get(&state);
34  STOP_TIMER("624 calls of av_lfg_get");
35  }
36  av_log(NULL, AV_LOG_ERROR, "final value:%X\n", x);
37 
38  /* BMG usage example */
39  {
40  double mean = 1000;
41  double stddev = 53;
42 
43  av_lfg_init(&state, 42);
44 
45  for (i = 0; i < 1000; i += 2) {
46  double bmg_out[2];
47  av_bmg_get(&state, bmg_out);
49  "%f\n%f\n",
50  bmg_out[0] * stddev + mean,
51  bmg_out[1] * stddev + mean);
52  }
53  }
54 
55  return 0;
56 }
Definition: lfg.h:25
av_log(ac->avr, AV_LOG_TRACE, "%d samples - audio_convert: %s to %s (%s)\, len, av_get_sample_fmt_name(ac->in_fmt), av_get_sample_fmt_name(ac->out_fmt), use_generic ? ac->func_descr_generic :ac->func_descr)
uint64_t i
Definition: intfloat.h:33
void av_bmg_get(AVLFG *lfg, double out[2])
Get the next two numbers generated by a Box-Muller Gaussian generator using the random numbers issued...
Definition: lfg.c:47
high precision timer, useful to profile code
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:124
NULL
Definition: eval.c:55
#define AV_LOG_INFO
Standard information.
Definition: log.h:135
#define START_TIMER
Definition: timer.h:86
static unsigned int av_lfg_get(AVLFG *c)
Get the next random unsigned 32-bit number using an ALFG.
Definition: lfg.h:38
av_cold void av_lfg_init(AVLFG *c, unsigned int seed)
Definition: lfg.c:30
static struct @174 state
#define STOP_TIMER(id)
Definition: timer.h:87
int main(void)
Definition: lfg.c:23