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

Class AbstractL128

java.lang.Object

org.apache.commons.rng.core.BaseProvider

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

org.apache.commons.rng.core.source64.AbstractL128

All Implemented Interfaces:

RandomLongSource, JumpableUniformRandomProvider, LongJumpableUniformRandomProvider, RestorableUniformRandomProvider, UniformRandomProvider

Direct Known Subclasses:

L128X1024Mix, L128X128Mix, L128X256Mix

abstract class AbstractL128
extends LongProvider
implements LongJumpableUniformRandomProvider

This abstract class is a base for algorithms from the LXM family of generators with a 128-bit LCG sub-generator. The class implements the jump functions.

Since:

1.5

Field Summary

Fields

Modifier and Type	Field	Description
protected long	lah	High half of the 128-bit per-instance LCG additive parameter.
protected long	lal	Low half of the 128-bit per-instance LCG additive parameter (must be odd).
protected long	lsh	High half of the 128-bit state of the LCG generator.
protected long	lsl	Low half of the 128-bit state of the LCG generator.
private static final long	ML	Low half of 128-bit LCG multiplier.
private static final int	SEED_SIZE	Size of the seed vector.

Constructor Summary

Constructors

Constructor	Description
AbstractL128(long[] seed)	Creates a new instance.
AbstractL128(long seed0, long seed1, long seed2, long seed3)	Creates a new instance using a 4 element seed.
AbstractL128(AbstractL128 source)	Creates a copy instance.

Method Summary

Modifier and Type	Method	Description
(package private) abstract AbstractL128	copy()	Create a copy.
protected byte[]	getStateInternal()	Creates a snapshot of the RNG state.
UniformRandomProvider	jump()	Creates a copy of the UniformRandomProvider and then retreats the state of the current instance.
JumpableUniformRandomProvider	longJump()	Creates a copy of the UniformRandomProvider and then retreats the state of the current instance.
private void	setState(long[] state)	Copies the state into the generator state.
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.core.source64.RandomLongSource

next

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 Details

SEED_SIZE

private static final int SEED_SIZE

Size of the seed vector.

See Also:

• Constant Field Values

ML

private static final long ML

Low half of 128-bit LCG multiplier.

See Also:

• Constant Field Values

lah

protected long lah

High half of the 128-bit per-instance LCG additive parameter. Cannot be final to support RestorableUniformRandomProvider.

lal

protected long lal

Low half of the 128-bit per-instance LCG additive parameter (must be odd). Cannot be final to support RestorableUniformRandomProvider.

lsh

protected long lsh

High half of the 128-bit state of the LCG generator.

lsl

protected long lsl

Low half of the 128-bit state of the LCG generator.

Constructor Details

AbstractL128

AbstractL128(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.

The 1st and 2nd elements are used to set the LCG increment; the least significant bit is set to odd to ensure a full period LCG. The 3rd and 4th elements are used to set the LCG state.

AbstractL128

AbstractL128(long seed0,
 long seed1,
 long seed2,
 long seed3)

Creates a new instance using a 4 element seed.

The 1st and 2nd elements are used to set the LCG increment; the least significant bit is set to odd to ensure a full period LCG. The 3rd and 4th elements are used to set the LCG state.

Parameters:

seed0 - Initial seed element 0.

seed1 - Initial seed element 1.

seed2 - Initial seed element 2.

seed3 - Initial seed element 3.

AbstractL128

AbstractL128(AbstractL128 source)

Creates a copy instance.

Parameters:

source - Source to copy.

Method Details

setState

private void setState(long[] state)

Copies the state 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)

jump

public UniformRandomProvider jump()

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

The jump is performed by advancing the state of the LCG sub-generator by 1 cycle. The XBG state is unchanged.

Specified by:

jump in interface JumpableUniformRandomProvider

Returns:

A copy of the current state.

longJump

public JumpableUniformRandomProvider longJump()

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

The jump is performed by advancing the state of the LCG sub-generator by 2⁶⁴ cycles. The XBG state is unchanged.

Specified by:

longJump in interface LongJumpableUniformRandomProvider

Returns:

A copy of the current state.

copy

abstract AbstractL128 copy()

Create a copy.

Returns:

the copy