2 * This file is part of FFmpeg.
4 * FFmpeg 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.
9 * FFmpeg 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.
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with FFmpeg; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 #include "libavutil/log.h"
20 #include "libavutil/timer.h"
21 #include "libavutil/lfg.h"
29 av_lfg_init(&state, 0xdeadbeef);
30 for (j = 0; j < 10000; j++) {
32 for (i = 0; i < 624; i++) {
33 //av_log(NULL, AV_LOG_ERROR, "%X\n", av_lfg_get(&state));
34 x += av_lfg_get(&state);
36 STOP_TIMER("624 calls of av_lfg_get");
38 av_log(NULL, AV_LOG_ERROR, "final value:%X\n", x);
40 /* BMG usage example */
44 double samp_mean = 0.0, samp_stddev = 0.0;
47 av_lfg_init(&state, 42);
49 for (i = 0; i < 1000; i += 2) {
51 av_bmg_get(&state, bmg_out);
52 samp0 = bmg_out[0] * stddev + mean;
53 samp1 = bmg_out[1] * stddev + mean;
54 samp_mean += samp0 + samp1;
55 samp_stddev += samp0 * samp0 + samp1 * samp1;
56 av_log(NULL, AV_LOG_INFO,
61 /* TODO: add proper normality test */
64 samp_stddev -= (1000.0/999.0)*samp_mean*samp_mean;
65 samp_stddev = sqrt(samp_stddev);
66 av_log(NULL, AV_LOG_INFO, "sample mean : %f\n"
70 samp_mean, mean, samp_stddev, stddev);