Class AbstractXoShiRo512

java.lang.Object

org.apache.commons.rng.core.BaseProvider

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

org.apache.commons.rng.core.source64.AbstractXoShiRo512

All Implemented Interfaces:

RandomLongSource, JumpableUniformRandomProvider, LongJumpableUniformRandomProvider, RestorableUniformRandomProvider, UniformRandomProvider

Direct Known Subclasses:

XoShiRo512Plus, XoShiRo512PlusPlus, XoShiRo512StarStar

abstract class AbstractXoShiRo512
extends LongProvider
implements LongJumpableUniformRandomProvider

This abstract class is a base for algorithms from the Xor-Shift-Rotate family of 64-bit generators with 512-bits of state.

Since:

1.3

See Also:

• xorshiro / xoroshiro generators

Field Summary

Fields

Modifier and Type	Field	Description
private static final long[]	JUMP_COEFFICIENTS	The coefficients for the jump function.
private static final long[]	LONG_JUMP_COEFFICIENTS	The coefficients for the long jump function.
private static final int	SEED_SIZE	Size of the state vector.
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.
protected long	state4	State 4 of the generator.
protected long	state5	State 5 of the generator.
protected long	state6	State 6 of the generator.
protected long	state7	State 7 of the generator.

Constructor Summary

Constructors

Modifier	Constructor	Description
(package private)	AbstractXoShiRo512(long[] seed)	Creates a new instance.
(package private)	AbstractXoShiRo512(long seed0, long seed1, long seed2, long seed3, long seed4, long seed5, long seed6, long seed7)	Creates a new instance using an 8 element seed.
protected	AbstractXoShiRo512(AbstractXoShiRo512 source)	Creates a copy instance.

Method Summary

Modifier and Type	Method	Description
protected abstract AbstractXoShiRo512	copy()	Create a copy.
protected byte[]	getStateInternal()	Creates a snapshot of the RNG state.
UniformRandomProvider	jump()	Creates a copy of the UniformRandomProvider and then advances the state of the current instance.
JumpableUniformRandomProvider	longJump()	Creates a copy of the JumpableUniformRandomProvider and then advances the state of the current instance.
long	next()	Return the next random value.
protected abstract long	nextOutput()	Use the current state to compute the next output from the generator.
private void	performJump(long[] jumpCoefficients)	Perform the jump to advance the generator state.
private void	setState(long[] state)	Copies the state from the array into the generator state.
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 JumpableUniformRandomProvider

jumps, jumps

Methods inherited from interface LongJumpableUniformRandomProvider

longJumps, longJumps

Methods inherited from interface 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 Details

SEED_SIZE

private static final int SEED_SIZE

Size of the state vector.

See Also:

• Constant Field Values

JUMP_COEFFICIENTS

private static final long[] JUMP_COEFFICIENTS

The coefficients for the jump function.

LONG_JUMP_COEFFICIENTS

private static final long[] LONG_JUMP_COEFFICIENTS

The coefficients for the long jump function.

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.

state4

protected long state4

State 4 of the generator.

state5

protected long state5

State 5 of the generator.

state6

protected long state6

State 6 of the generator.

state7

protected long state7

State 7 of the generator.

Constructor Details

AbstractXoShiRo512

AbstractXoShiRo512(long[] seed)

Creates a new instance.

Parameters:

seed - Initial seed. If the length is larger than 8, only the first 8 elements will be used; if smaller, the remaining elements will be automatically set. A seed containing all zeros will create a non-functional generator.

AbstractXoShiRo512

AbstractXoShiRo512(long seed0,
 long seed1,
 long seed2,
 long seed3,
 long seed4,
 long seed5,
 long seed6,
 long seed7)

Creates a new instance using an 8 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.

seed4 - Initial seed element 4.

seed5 - Initial seed element 5.

seed6 - Initial seed element 6.

seed7 - Initial seed element 7.

AbstractXoShiRo512

protected AbstractXoShiRo512(AbstractXoShiRo512 source)

Creates a copy instance.

Parameters:

source - Source to copy.

Method Details

setState

private void setState(long[] state)

Copies the state from the array into the generator state.

Parameters:

state - the new state

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()

Return the next random value.

Specified by:

next in interface RandomLongSource

Returns:

the next random value.

nextOutput

protected abstract 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

jump

public UniformRandomProvider jump()

Creates a copy of the UniformRandomProvider and then advances the state of the current instance. The copy is returned.

The current state will be advanced in a single operation by the equivalent of a number of sequential calls to a method that updates the state of the provider. The size of the jump is implementation dependent.

Repeat invocations of this method will create a series of generators that are uniformly spaced at intervals of the output sequence. Each generator provides non-overlapping output for the length of the jump for use in parallel computations.

The jump size is the equivalent of 2²⁵⁶ calls to nextLong(). It can provide up to 2²⁵⁶ non-overlapping subsequences.

Specified by:

jump in interface JumpableUniformRandomProvider

Returns:

A copy of the current state.

longJump

public JumpableUniformRandomProvider longJump()

Creates a copy of the JumpableUniformRandomProvider and then advances the state of the current instance. The copy is returned.

The current state will be advanced in a single operation by the equivalent of a number of sequential calls to a method that updates the state of the provider. The size of the long jump is implementation dependent.

Repeat invocations of this method will create a series of generators that are uniformly spaced at intervals of the output sequence. Each generator provides non-overlapping output for the length of the long jump for use in parallel computations.

The returned copy may be jumped m / n times before overlap with the current instance where m is the long jump length and n is the jump length of the JumpableUniformRandomProvider.jump() method.

The jump size is the equivalent of 2³⁸⁴ calls to nextLong(). It can provide up to 2¹²⁸ non-overlapping subsequences of length 2³⁸⁴; each subsequence can provide up to 2¹²⁸ non-overlapping subsequences of length 2²⁵⁶ using the jump() method.

Specified by:

longJump in interface LongJumpableUniformRandomProvider

Returns:

A copy of the current state.

copy

protected abstract AbstractXoShiRo512 copy()

Create a copy.

Returns:

the copy

performJump

private void performJump(long[] jumpCoefficients)

Perform the jump to advance the generator state. Resets the cached state of the generator.

Parameters:

jumpCoefficients - Jump coefficients.