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

Class XoShiRo256StarStar

java.lang.Object

org.apache.commons.rng.core.BaseProvider

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

org.apache.commons.rng.core.source64.XoShiRo256StarStar

All Implemented Interfaces:

RandomLongSource, JumpableUniformRandomProvider, LongJumpableUniformRandomProvider, RestorableUniformRandomProvider, UniformRandomProvider

public class XoShiRo256StarStar
extends LongProvider

A fast all-purpose 64-bit generator.

This is a member of the Xor-Shift-Rotate family of generators. Memory footprint is 256 bits and the period is 2²⁵⁶-1.

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.
protected long	state2	State 2 of the generator.
protected long	state3	State 3 of the generator.

Constructor Summary

Constructors

Modifier	Constructor	Description
	XoShiRo256StarStar(long[] seed)	Creates a new instance.
	XoShiRo256StarStar(long seed0, long seed1, long seed2, long seed3)	Creates a new instance using a 4 element seed.
protected	XoShiRo256StarStar(XoShiRo256StarStar source)	Creates a copy instance.

Method Summary

Modifier and Type	Method	Description
protected XoShiRo256StarStar	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.BaseProvider

checkIndex, checkStateSize, composeStateInternal, fillState, fillState, nextInt, nextLong, restoreState, saveState, splitStateInternal, toString

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

nextBoolean, nextBytes, nextBytes, nextDouble, nextFloat, nextInt, nextLong, resetCachedState

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.UniformRandomProvider

nextBoolean, nextBytes, nextBytes, nextDouble, nextFloat, nextInt, nextInt, nextLong, nextLong

Field Detail

state0

protected long state0

State 0 of the generator.

state1

protected long state1

State 1 of the generator.

state2

protected long state2

State 2 of the generator.

state3

protected long state3

State 3 of the generator.

Constructor Detail

XoShiRo256StarStar

public XoShiRo256StarStar(long[] seed)

Creates a new instance.

Parameters:

seed - Initial seed. If the length is larger than 4, only the first 4 elements will be used; if smaller, the remaining elements will be automatically set. A seed containing all zeros will create a non-functional generator.

XoShiRo256StarStar

public XoShiRo256StarStar(long seed0,
                          long seed1,
                          long seed2,
                          long seed3)

Creates a new instance using a 4 element seed. A seed containing all zeros will create a non-functional generator.

Parameters:

seed0 - Initial seed element 0.

seed1 - Initial seed element 1.

seed2 - Initial seed element 2.

seed3 - Initial seed element 3.

XoShiRo256StarStar

protected XoShiRo256StarStar(XoShiRo256StarStar 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 next() before the current state is updated.

Returns:

the next output

copy

protected XoShiRo256StarStar 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 2¹²⁸ calls to nextLong(). It can provide up to 2¹²⁸ non-overlapping subsequences.

Specified by:

jump in interface JumpableUniformRandomProvider

longJump

public JumpableUniformRandomProvider longJump()

The jump size is the equivalent of 2¹⁹² calls to nextLong(). It can provide up to 2⁶⁴ non-overlapping subsequences of length 2¹⁹²; each subsequence can provide up to 2⁶⁴ non-overlapping subsequences of length 2¹²⁸using the jump() method.

Specified by:

longJump in interface LongJumpableUniformRandomProvider