Class PcgRxsMXs64

java.lang.Object

org.apache.commons.rng.core.BaseProvider

org.apache.commons.rng.core.source64.LongProvider

org.apache.commons.rng.core.source64.PcgRxsMXs64

All Implemented Interfaces:

RandomLongSource, RestorableUniformRandomProvider, UniformRandomProvider

public class PcgRxsMXs64
extends LongProvider

A Permuted Congruential Generator (PCG) that is composed of a 64-bit Linear Congruential Generator (LCG) combined with the RXS-M-XS (random xorshift; multiply; xorshift) output transformation to create 64-bit output.

State size is 128 bits and the period is 2⁶⁴.

Note: Although the seed size is 128 bits, only the first 64 are effective: in effect, two seeds that only differ by the last 64 bits may produce highly correlated sequences.

Since:

1.3

See Also:

• PCG, A Family of Better Random Number Generators

Constructor Summary

Constructors

Constructor	Description
PcgRxsMXs64(long[] seed)	Creates a new instance.
PcgRxsMXs64(Long seed)	Creates a new instance using a default increment.

Method Summary

Modifier and Type	Method	Description
protected byte[]	getStateInternal()	Creates a snapshot of the RNG state.
long	next()	Return the next random value.
protected void	setStateInternal(byte[] s)	Resets the RNG to the given state.

Methods inherited from class LongProvider

nextBoolean, nextInt, nextLong, resetCachedState

Methods inherited from class BaseProvider

checkIndex, checkStateSize, composeStateInternal, extendSeed, extendSeed, fillState, fillState, restoreState, saveState, splitStateInternal, toString

Methods inherited from class Object

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

Methods inherited from interface UniformRandomProvider

doubles, doubles, doubles, doubles, ints, ints, ints, ints, longs, longs, longs, longs, nextBytes, nextBytes, nextDouble, nextDouble, nextDouble, nextFloat, nextFloat, nextFloat, nextInt, nextInt, nextLong, nextLong

Constructor Details

PcgRxsMXs64

public PcgRxsMXs64(Long seed)

Creates a new instance using a default increment.

Parameters:

seed - Initial state.

Since:

1.4

PcgRxsMXs64

public PcgRxsMXs64(long[] seed)

Creates a new instance.

Note: Although the seed size is 128 bits, only the first 64 are effective: in effect, two seeds that only differ by the last 64 bits may produce highly correlated sequences.

Parameters:

seed - Initial seed. If the length is larger than 2, only the first 2 elements will be used; if smaller, the remaining elements will be automatically set.

The 1st element is used to set the LCG state. The 2nd element is used to set the LCG increment; the most significant bit is discarded by left shift and the increment is set to odd.

Method Details

next

public long next()

Return the next random value.

Returns:

the next random value.

getStateInternal

protected byte[] getStateInternal()

Creates a snapshot of the RNG state.

Overrides:

getStateInternal in class LongProvider

Returns:

the internal state.

setStateInternal

protected void setStateInternal(byte[] s)

Resets the RNG to the given state.

Overrides:

setStateInternal in class LongProvider

Parameters:

s - State (previously obtained by a call to BaseProvider.getStateInternal()).

See Also:

• BaseProvider.checkStateSize(byte[],int)