Package org.apache.commons.rng.simple

Class ThreadLocalRandomSource

java.lang.Object

org.apache.commons.rng.simple.ThreadLocalRandomSource

public final class ThreadLocalRandomSource
extends Object

This class provides a thread-local UniformRandomProvider.

The UniformRandomProvider is created once-per-thread using the default construction method RandomSource.create().

Example:

 import org.apache.commons.rng.simple.RandomSource;
 import org.apache.commons.rng.simple.ThreadLocalRandomSource;
 import org.apache.commons.rng.sampling.distribution.PoissonSampler;

 // Access a thread-safe random number generator
 UniformRandomProvider rng = ThreadLocalRandomSource.current(RandomSource.SPLIT_MIX_64);

 // One-time Poisson sample
 double mean = 12.3;
 int counts = PoissonSampler.of(rng, mean).sample();
 

Note if the RandomSource requires additional arguments then it is not supported. The same can be achieved using:

 import org.apache.commons.rng.simple.RandomSource;
 import org.apache.commons.rng.sampling.distribution.PoissonSampler;

 // Provide a thread-safe random number generator with data arguments
 private static ThreadLocal<UniformRandomProvider> rng =
     new ThreadLocal<UniformRandomProvider>() {
         @Override
         protected UniformRandomProvider initialValue() {
             return RandomSource.TWO_CMRES_SELECT.create(null, 3, 4);
         }
     };

 // One-time Poisson sample using a thread-safe random number generator
 double mean = 12.3;
 int counts = PoissonSampler.of(rng.get(), mean).sample();
 

Since:

1.3

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	ThreadLocalRandomSource.ThreadLocalRng	Extend the ThreadLocal to allow creation of the desired RandomSource.

Field Summary

Fields

Modifier and Type	Field	Description
private static final Map<RandomSource,ThreadLocal<UniformRandomProvider>>	SOURCES	A map containing the ThreadLocal instance for each RandomSource.

Constructor Summary

Constructors

Modifier	Constructor	Description
private	ThreadLocalRandomSource()	No public construction.

Method Summary

Modifier and Type	Method	Description
static UniformRandomProvider	current(RandomSource source)	Returns the current thread's copy of the given source.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

SOURCES

private static final Map<RandomSource,ThreadLocal<UniformRandomProvider>> SOURCES

A map containing the ThreadLocal instance for each RandomSource.

This should only be modified to create new instances in a synchronized block.

Constructor Details

ThreadLocalRandomSource

private ThreadLocalRandomSource()

No public construction.

Method Details

current

public static UniformRandomProvider current(RandomSource source)

Returns the current thread's copy of the given source. If there is no value for the current thread, it is first initialized to the value returned by RandomSource.create().

Note if the source requires additional arguments then it is not supported.

Parameters:

source - the source

Returns:

the current thread's value of the source.

Throws:

IllegalArgumentException - if the source is null or the source requires arguments