[RNG-57] CachedUniformRandomProvider for nextBoolean() and nextInt()

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Implemented
• Fix Version/s: 1.2
• Component/s: core
• Labels: performance
• Assignee: Unassigned
• Reporter: Alex Herbert
• Created: 24/Sep/18 13:48
• Updated: 18/Mar/22 09:22
• Resolved: 27/Nov/18 11:20

Description

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.

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...));

The implementation should be speed tested to determine the benefit for nextBoolean() and if nextInt() can be improved for LongProviders.

Issue Links

• depends upon: RNG-58 Allow part of the RNG state to be stored in base classes of the hierarchy
• relates to: RNG-171 Reduce memory footprint of cached int and boolean source
• relates to: RNG-80 Benchmark SplitMix64 to natively generate nextInt
• links to: GitHub Pull Request #11
• links to: GitHub Pull Request #12