Class CMWC4096RNG

java.lang.Object

java.util.Random

org.uncommons.maths.random.CMWC4096RNG

All Implemented Interfaces:

Serializable, RandomGenerator, RepeatableRNG

public class CMWC4096RNG
extends Random
implements RepeatableRNG

A Java version of George Marsaglia's Complementary Multiply With Carry (CMWC) RNG. This is a very fast PRNG with an extremely long period (2^131104). It should be used in preference to the MersenneTwisterRNG when a very long period is required.

One potential drawback of this RNG is that it requires significantly more seed data than the other RNGs provided by Uncommons Maths. It requires just over 16 kilobytes, which may be a problem if your are obtaining seed data from a slow or limited entropy source. In contrast, the Mersenne Twister requires only 128 bits of seed data.

NOTE: Because instances of this class require 16-kilobyte seeds, it is not possible to seed this RNG using the Random.setSeed(long) method inherited from Random. Calls to this method will have no effect. Instead the seed must be set by a constructor.

Since:

1.2

See Also:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface RandomGenerator

RandomGenerator.ArbitrarilyJumpableGenerator, RandomGenerator.JumpableGenerator, RandomGenerator.LeapableGenerator, RandomGenerator.SplittableGenerator, RandomGenerator.StreamableGenerator

Field Summary

Fields

Modifier and Type	Field	Description
private static final long	A
private int	carry
private int	index
private final ReentrantLock	lock
private final byte[]	seed
private static final int	SEED_SIZE_BYTES
private final int[]	state

Constructor Summary

Constructors

Constructor	Description
CMWC4096RNG()	Creates a new RNG and seeds it using the default seeding strategy.
CMWC4096RNG(byte[] seed)	Creates an RNG and seeds it with the specified seed data.
CMWC4096RNG(SeedGenerator seedGenerator)	Seed the RNG using the provided seed generation strategy.

Method Summary

Modifier and Type	Method	Description
byte[]	getSeed()
protected int	next(int bits)

Methods inherited from class Random

doubles, doubles, doubles, doubles, from, ints, ints, ints, ints, longs, longs, longs, longs, nextBoolean, nextBytes, nextDouble, nextFloat, nextGaussian, nextInt, nextInt, nextLong, setSeed

Methods inherited from class Object

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

Methods inherited from interface RandomGenerator

equiDoubles, isDeprecated, nextDouble, nextDouble, nextExponential, nextFloat, nextFloat, nextGaussian, nextInt, nextLong, nextLong

Field Details

SEED_SIZE_BYTES

private static final int SEED_SIZE_BYTES

See Also:

• Constant Field Values

A

private static final long A

See Also:

• Constant Field Values

seed

private final byte[] seed

state

private final int[] state

carry

private int carry

index

private int index

lock

private final ReentrantLock lock

Constructor Details

CMWC4096RNG

public CMWC4096RNG()

Creates a new RNG and seeds it using the default seeding strategy.

CMWC4096RNG

public CMWC4096RNG(SeedGenerator seedGenerator)
            throws SeedException

Seed the RNG using the provided seed generation strategy.

Parameters:

seedGenerator - The seed generation strategy that will provide the seed value for this RNG.

Throws:

SeedException - If there is a problem generating a seed.

CMWC4096RNG

public CMWC4096RNG(byte[] seed)

Creates an RNG and seeds it with the specified seed data.

Parameters:

seed - The seed data used to initialise the RNG.

Method Details

getSeed

public byte[] getSeed()

Specified by:

getSeed in interface RepeatableRNG

Returns:

The seed data used to initialise this pseudo-random number generator.

next

protected int next(int bits)

Overrides:

next in class Random