org.apache.commons.math.random
Class Well19937a

java.lang.Object
  extended by org.apache.commons.math.random.BitsStreamGenerator
      extended by org.apache.commons.math.random.AbstractWell
          extended by org.apache.commons.math.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:
$Revision: 1003892 $ $Date: 2010-10-02 23:28:56 +0200 (sam. 02 oct. 2010) $
See Also:
WELL Random number generator, Serialized Form

Field Summary
private static int K
          Number of bits in the pool.
private static int M1
          First parameter of the algorithm.
private static int M2
          Second parameter of the algorithm.
private static int M3
          Third parameter of the algorithm.
private static long serialVersionUID
          Serializable version identifier.
 
Fields inherited from class org.apache.commons.math.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.math.random.AbstractWell
setSeed, setSeed, setSeed
 
Methods inherited from class org.apache.commons.math.random.BitsStreamGenerator
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
 

Field Detail

serialVersionUID

private static final long serialVersionUID
Serializable version identifier.

See Also:
Constant Field Values

K

private static final int K
Number of bits in the pool.

See Also:
Constant Field Values

M1

private static final int M1
First parameter of the algorithm.

See Also:
Constant Field Values

M2

private static final int M2
Second parameter of the algorithm.

See Also:
Constant Field Values

M3

private static final int M3
Third parameter of the algorithm.

See Also:
Constant Field Values
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


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