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From "Gilles (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (RNG-57) CachedUniformRandomProvider for nextBoolean() and nextInt()
Date Tue, 02 Oct 2018 20:09:00 GMT

    [ https://issues.apache.org/jira/browse/RNG-57?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16636051#comment-16636051
] 

Gilles commented on RNG-57:
---------------------------

{quote}I think it is necessary as the nextInt from the long provider only used the lower 32-bits.
It is possible these providers do not have as much randomness in the upper 32-bits. The only
way to know is to rerun the tests.
{quote}
You are right indeed.
 Given that is the stress test suites are quite time-consuming (especially "Big Crush" of
TestU01), I'll rerun them after the "feature-freeze". ;)

bq. Unless you really want the history of the testing preserved somehow.

I don't think that it is necessary; this JIRA report documents pretty well that your analysis
has been fairly thorough and led to the best alternative being committed into the code repository.

> CachedUniformRandomProvider for nextBoolean() and nextInt()
> -----------------------------------------------------------
>
>                 Key: RNG-57
>                 URL: https://issues.apache.org/jira/browse/RNG-57
>             Project: Commons RNG
>          Issue Type: Improvement
>          Components: sampling
>    Affects Versions: 1.2
>            Reporter: Alex D Herbert
>            Priority: Minor
>              Labels: performance
>
> Implement a wrapper around a {{UniformRandomProvider}} that can cache the underlying
source of random bytes for use in the methods {{nextBoolean()}} and {{nextInt()}} (in the
case of {{LongProvider}}). E.g.
> {code:java}
> LongProvider provider = RandomSource.create(RandomSource.SPLIT_MIX_64);
> CachedLongProvider rng = new CachedLongProvider(provider);
> // Uses cached nextLong() 64 times
> rng.nextBoolean();
> // Uses cached nextLong() twice
> rng.nextInt();
> IntProvider provider = RandomSource.create(RandomSource.KISS);
> CachedIntProvider rng2 = new CachedIntProvider(provider);
> // Uses cached nextInt() 32 times
> rng2.nextBoolean();
> // This could be wrapped by a factory method:
> UniformRandomProvider rng = CachedUniformRandomProviderFactory.wrap(
>         // Any supported source: IntProvider or LongProvider
>         RandomSource.create(RandomSource...));
> {code}
> The implementation should be speed tested to determine the benefit for {{nextBoolean()}}
and if {{nextInt()}} can be improved for {{LongProviders}}.



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