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From Gilles Sadowski <gillese...@gmail.com>
Subject Re: [rng] BigCrush results
Date Mon, 07 Oct 2019 14:00:57 GMT
Hi.

Le lun. 7 oct. 2019 à 15:54, Alex Herbert <alex.d.herbert@gmail.com> a écrit :
>
> I have found a bug in the stress test application that affects all the
> BigCrush results.
>
> This was found when updating the stress test application to support
> 64-bit testing within PractRand, and testing of upper and lower 32-bits
> from 64-bit out. An initial attempt to show that the lower 32-bits, bit
> reversed, of the XOR_SHIFT_1024_S systematically fail Linear Complexity
> tests did not work.
>
> The bug was a dual reversal of the platform byte-order. Code was added
> to reverse the byte order in the link c application that read from stdin
> and passes numbers to BigCrush. Later code was added to reverse the byte
> order in the Java application so allowing Dieharder to work. The
> original c application should have been updated but was not (despite the
> fact I thought I had done this). So the byte order was not correct after
> a dual reversal and the BigCrush results refer to a byte reversed output
> sequence.
>
> I fixed the code and have verified that the stress test application can
> identify Linear Complexity failures in XOR_SHIFT_1024_S.
>
> I am rerunning BigCrush for the other generators.
>
> Testing of generators with PractRand is still under trial and will
> probably not make it for the 1.3 release. The only outstanding item for
> 1.3 is continued work on updating the user guide.

The userguide (and web site) can be updated at any time (between
releases); it is not be a blocker.

Best regards,
Gilles

>
> Alex

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