[FFmpeg-devel] [PATCH] avutil/tests/lfg.c: added proper normality test

[Michael Niedermayer]

On Tue, Jan 31, 2017 at 07:56:39PM -0800, Thomas Turner wrote:
> The Chen-Shapiro(CS) test was used to test normality for
> Lagged Fibonacci PRNG.
> 
> Normality Hypothesis Test:
> 
> The null hypothesis formally tests if the population
> the sample represents is normally-distributed. For
> CS, when the normality hypothesis is True, the
> distribution of QH will have a mean close to 1.
> 
> Information on CS can be found here:
> 
> http://www.stata-journal.com/sjpdf.html?articlenum=st0264
> http://www.originlab.com/doc/Origin-Help/NormalityTest-Algorithm
> 
[...]
> diff --git a/tests/fate/libavutil.mak b/tests/fate/libavutil.mak
> index a7bf739..c3b9091 100644
> --- a/tests/fate/libavutil.mak
> +++ b/tests/fate/libavutil.mak
> @@ -101,6 +101,11 @@ FATE_LIBAVUTIL += fate-imgutils
>  fate-imgutils: libavutil/tests/imgutils$(EXESUF)
>  fate-imgutils: CMD = run libavutil/tests/imgutils
>  
> +FATE_LIBAVUTIL += fate-lfg
> +fate-lfg: libavutil/tests/lfg$(EXESUF)
> +fate-lfg: CMD = run libavutil/tests/lfg
> +fate-lfg: REF = /dev/null

This test does not work

for example with:
@@ -109,6 +109,7 @@ int main(void)
         for (i = 0; i < tot_samp; i += 2) {
             double bmg_out[2];
             av_bmg_get(&state, bmg_out);
+            bmg_out[0] = bmg_out[1]  = 0;
             PRN_arr[i  ] = bmg_out[0] * stddev + mean;
             PRN_arr[i+1] = bmg_out[1] * stddev + mean;
             samp_mean   += PRN_arr[i] + PRN_arr[i+1];

"make fate-lfg" still passes

[...]
-- 
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