mirror of https://git.ffmpeg.org/ffmpeg.git
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: Michael Niedermayer <michael@niedermayer.cc> Signed-off-by: Ganesh Ajjanagadde <gajjanag@gmail.com>
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@ -84,17 +84,33 @@ int main(void)
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{
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double mean = 1000;
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double stddev = 53;
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double samp_mean = 0.0, samp_stddev = 0.0;
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double samp0, samp1;
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av_lfg_init(&state, 42);
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for (i = 0; i < 1000; i += 2) {
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double bmg_out[2];
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av_bmg_get(&state, bmg_out);
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samp0 = bmg_out[0] * stddev + mean;
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samp1 = bmg_out[1] * stddev + mean;
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samp_mean += samp0 + samp1;
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samp_stddev += samp0 * samp0 + samp1 * samp1;
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av_log(NULL, AV_LOG_INFO,
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"%f\n%f\n",
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bmg_out[0] * stddev + mean,
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bmg_out[1] * stddev + mean);
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samp0,
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samp1);
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}
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/* TODO: add proper normality test */
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samp_mean /= 1000;
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samp_stddev /= 999;
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samp_stddev -= (1000.0/999.0)*samp_mean*samp_mean;
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samp_stddev = sqrt(samp_stddev);
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av_log(NULL, AV_LOG_INFO, "sample mean : %f\n"
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"true mean : %f\n"
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"sample stddev: %f\n"
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"true stddev : %f\n",
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samp_mean, mean, samp_stddev, stddev);
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}
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return 0;
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