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From Alex Herbert <>
Subject Re: [rng] BigCrush results
Date Mon, 07 Oct 2019 14:21:21 GMT

On 07/10/2019 15:00, Gilles Sadowski wrote:
> Hi.
> Le lun. 7 oct. 2019 à 15:54, Alex Herbert <> 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.


I am just going through adding the new parts of the code to it. As part 
of this process I am finding a few niggles that I am fixing. I'm also 
addressing the SonarCloud report. So far I've found a few things that 
add value to the release so I'd prefer to finish this. I think in a week 
it should be all done. Getting a release out would be good.

> Best regards,
> Gilles
>> Alex
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