org.apache.commons.math3.random
Class Well19937a

java.lang.Object
  org.apache.commons.math3.random.BitsStreamGenerator
      org.apache.commons.math3.random.AbstractWell
          org.apache.commons.math3.random.Well19937a

All Implemented Interfaces:

Serializable, RandomGenerator

public class Well19937a
extends AbstractWell

This class implements the WELL19937a pseudo-random number generator from François Panneton, Pierre L'Ecuyer and Makoto Matsumoto.

This generator is described in a paper by François Panneton, Pierre L'Ecuyer and Makoto Matsumoto Improved Long-Period Generators Based on Linear Recurrences Modulo 2 ACM Transactions on Mathematical Software, 32, 1 (2006). The errata for the paper are in wellrng-errata.txt.

Since:

2.2

Version:

$Id: Well19937a.java 3720 2012-03-16 16:34:17Z CardosoP $

See Also:

WELL Random number generator, Serialized Form

Field Summary

Fields inherited from class org.apache.commons.math3.random.AbstractWell

i1, i2, i3, index, iRm1, iRm2, v

Constructor Summary

Well19937a()
Creates a new random number generator.

Well19937a(int seed)
Creates a new random number generator using a single int seed.

Well19937a(int[] seed)
Creates a new random number generator using an int array seed.

Well19937a(long seed)
Creates a new random number generator using a single long seed.

Method Summary

protected int

next(int bits) Generate next pseudorandom number.

Methods inherited from class org.apache.commons.math3.random.AbstractWell

setSeed, setSeed, setSeed

Methods inherited from class org.apache.commons.math3.random.BitsStreamGenerator

clear, nextBoolean, nextBytes, nextDouble, nextFloat, nextGaussian, nextInt, nextInt, nextLong

Methods inherited from class java.lang.Object

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

Constructor Detail

Well19937a

public Well19937a()

Creates a new random number generator.

The instance is initialized using the current time as the seed.

Well19937a

public Well19937a(int seed)

Creates a new random number generator using a single int seed.

Parameters:

seed - the initial seed (32 bits integer)

Well19937a

public Well19937a(int[] seed)

Creates a new random number generator using an int array seed.

Parameters:

seed - the initial seed (32 bits integers array), if null the seed of the generator will be related to the current time

Well19937a

public Well19937a(long seed)

Creates a new random number generator using a single long seed.

Parameters:

seed - the initial seed (64 bits integer)

Method Detail

next

protected int next(int bits)

Generate next pseudorandom number.

This method is the core generation algorithm. It is used by all the public generation methods for the various primitive types BitsStreamGenerator.nextBoolean(), BitsStreamGenerator.nextBytes(byte[]), BitsStreamGenerator.nextDouble(), BitsStreamGenerator.nextFloat(), BitsStreamGenerator.nextGaussian(), BitsStreamGenerator.nextInt(), BitsStreamGenerator.next(int) and BitsStreamGenerator.nextLong().

Specified by:

next in class AbstractWell

Parameters:

bits - number of random bits to produce

Returns:

random bits generated