Commit 0c33ceda authored by Ganesh Ajjanagadde's avatar Ganesh Ajjanagadde

lavu/lfg-test: add simple sample mean, stddev checks

Also added a TODO to change to a proper normality test in the future.
Reviewed-by: 's avatarMichael Niedermayer <michael@niedermayer.cc>
Signed-off-by: 's avatarGanesh Ajjanagadde <gajjanag@gmail.com>
parent bdc798cc
...@@ -84,17 +84,33 @@ int main(void) ...@@ -84,17 +84,33 @@ int main(void)
{ {
double mean = 1000; double mean = 1000;
double stddev = 53; double stddev = 53;
double samp_mean = 0.0, samp_stddev = 0.0;
double samp0, samp1;
av_lfg_init(&state, 42); av_lfg_init(&state, 42);
for (i = 0; i < 1000; i += 2) { for (i = 0; i < 1000; i += 2) {
double bmg_out[2]; double bmg_out[2];
av_bmg_get(&state, bmg_out); 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, av_log(NULL, AV_LOG_INFO,
"%f\n%f\n", "%f\n%f\n",
bmg_out[0] * stddev + mean, samp0,
bmg_out[1] * stddev + mean); 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; return 0;
......
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