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From "Gilles (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (RNG-57) CachedUniformRandomProvider for nextBoolean() and nextInt()
Date Fri, 05 Oct 2018 21:07:00 GMT

    [ https://issues.apache.org/jira/browse/RNG-57?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16640345#comment-16640345
] 

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

bq. So parent should be first. It is also documented to work this way.

Actually not, as it would be confusing since in the code the "local" state comes first.

bq. So I've just added some comments in the code that the order is state+parent when combining
and splitting.

Thanks but it is the Javadoc example that needed fixing.
And all the calls in the implementations...

As you noted, the code in {{BaseProvider}} concatenates "local" + "parent", and is pretty
self-documenting.

I'll make a separate commit to fix.
Sorry for the mix-up!


> 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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