commons-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Gilles (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (RNG-57) CachedUniformRandomProvider for nextBoolean() and nextInt()
Date Tue, 25 Sep 2018 12:51:00 GMT

    [ https://issues.apache.org/jira/browse/RNG-57?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16627283#comment-16627283
] 

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

Nice results!

Concerning the design partially shown, I don't understand the purpose of a {{CachedUniformRandomProvider}}
interface; the cache is an _implementation_ detail.

Either the we provide a high-level "adapter" (through a factory method):
{code}
final UniformRandomProvider rng = RandomSource.cachingBoolean(UniformRandomProvider delegate)
{
    // Code which you proposed in the above comment: caching
    // for "nextBoolean()" and delegating the other methods.
}
{code}
or we assume that caching will always be as fast or faster than discarding data, and we implement
it in the "core" module.


> 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}}.



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)

Mime
View raw message