Package org.apache.commons.rng.core.source64

Class XoRoShiRo128StarStar

java.lang.Object

org.apache.commons.rng.core.BaseProvider

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

org.apache.commons.rng.core.source64.XoRoShiRo128StarStar

All Implemented Interfaces:

RandomLongSource, JumpableUniformRandomProvider, LongJumpableUniformRandomProvider, RestorableUniformRandomProvider, UniformRandomProvider

public class XoRoShiRo128StarStar
extends LongProvider

A fast all-purpose 64-bit generator.

This is a member of the Xor-Shift-Rotate family of generators. Memory footprint is 128 bits and the period is 2¹²⁸-1. Speed is expected to be similar to XoShiRo256StarStar.

Since:

1.3

See Also:

Original source code, xorshiro / xoroshiro generators

Field Summary

Fields

Modifier and Type	Field	Description
protected long	state0	State 0 of the generator.
protected long	state1	State 1 of the generator.

Constructor Summary

Constructors

Modifier	Constructor	Description
	XoRoShiRo128StarStar(long[] seed)	Creates a new instance.
	XoRoShiRo128StarStar(long seed0, long seed1)	Creates a new instance using a 2 element seed.
protected	XoRoShiRo128StarStar(XoRoShiRo128StarStar source)	Creates a copy instance.

Method Summary

Modifier and Type	Method	Description
protected XoRoShiRo128StarStar	copy()	Create a copy.
protected byte[]	getStateInternal()	Creates a snapshot of the RNG state.
UniformRandomProvider	jump()
JumpableUniformRandomProvider	longJump()
long	next()
protected long	nextOutput()	Use the current state to compute the next output from the generator.
protected void	setStateInternal(byte[] s)	Resets the RNG to the given state.

Methods inherited from class org.apache.commons.rng.core.source64.LongProvider

nextBoolean, nextInt, nextLong, resetCachedState

Methods inherited from class org.apache.commons.rng.core.BaseProvider

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

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.commons.rng.JumpableUniformRandomProvider

jumps, jumps

Methods inherited from interface org.apache.commons.rng.LongJumpableUniformRandomProvider

longJumps, longJumps

Methods inherited from interface org.apache.commons.rng.UniformRandomProvider

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

Field Detail

state0

protected long state0

State 0 of the generator.

state1

protected long state1

State 1 of the generator.

Constructor Detail

XoRoShiRo128StarStar

public XoRoShiRo128StarStar(long[] seed)

Creates a new instance.

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. A seed containing all zeros will create a non-functional generator.

XoRoShiRo128StarStar

public XoRoShiRo128StarStar(long seed0,
                            long seed1)

Creates a new instance using a 2 element seed. A seed containing all zeros will create a non-functional generator.

Parameters:

seed0 - Initial seed element 0.

seed1 - Initial seed element 1.

XoRoShiRo128StarStar

protected XoRoShiRo128StarStar(XoRoShiRo128StarStar source)

Creates a copy instance.

Parameters:

source - Source to copy.

Method Detail

nextOutput

protected long nextOutput()

Use the current state to compute the next output from the generator. The output function shall vary with respect to different generators. This method is called from RandomLongSource.next() before the current state is updated.

Returns:

the next output

copy

protected XoRoShiRo128StarStar copy()

Create a copy.

Returns:

the copy

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)

next

public long next()

Specified by:

next in interface RandomLongSource

Returns:

the next random value.

jump

public UniformRandomProvider jump()

The jump size is the equivalent of 2⁶⁴ calls to nextLong(). It can provide up to 2⁶⁴ non-overlapping subsequences.

Specified by:

jump in interface JumpableUniformRandomProvider

longJump

public JumpableUniformRandomProvider longJump()

The jump size is the equivalent of 2⁹⁶ calls to nextLong(). It can provide up to 2³² non-overlapping subsequences of length 2⁹⁶; each subsequence can provide up to 2³² non-overlapping subsequences of length 2⁶⁴ using the JumpableUniformRandomProvider.jump() method.

Specified by:

longJump in interface LongJumpableUniformRandomProvider