diff options
| -rw-r--r-- | libavutil/lfg.c | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/libavutil/lfg.c b/libavutil/lfg.c index ffa2f1fd3d..5ffd76f181 100644 --- a/libavutil/lfg.c +++ b/libavutil/lfg.c @@ -84,17 +84,33 @@ int main(void) { double mean = 1000; double stddev = 53; + double samp_mean = 0.0, samp_stddev = 0.0; + double samp0, samp1; av_lfg_init(&state, 42); for (i = 0; i < 1000; i += 2) { double bmg_out[2]; av_bmg_get(&state, bmg_out); + samp0 = bmg_out[0] * stddev + mean; + samp1 = bmg_out[1] * stddev + mean; + samp_mean += samp0 + samp1; + samp_stddev += samp0 * samp0 + samp1 * samp1; av_log(NULL, AV_LOG_INFO, "%f\n%f\n", - bmg_out[0] * stddev + mean, - bmg_out[1] * stddev + mean); + samp0, + samp1); } + /* TODO: add proper normality test */ + samp_mean /= 1000; + samp_stddev /= 999; + samp_stddev -= (1000.0/999.0)*samp_mean*samp_mean; + samp_stddev = sqrt(samp_stddev); + av_log(NULL, AV_LOG_INFO, "sample mean : %f\n" + "true mean : %f\n" + "sample stddev: %f\n" + "true stddev : %f\n", + samp_mean, mean, samp_stddev, stddev); } return 0; |