org.knowceans.util
Class CokusRandom

java.lang.Object
  java.util.Random
      org.knowceans.util.CokusRandom

All Implemented Interfaces:

java.io.Serializable

public class CokusRandom
extends java.util.Random

CokusRandom is a non-static version of the Cokus Mersenne Twister as a Random subclass. (Based on the C code used in LDA-C).

Note: nextUnsignedInt(), next(), and randDouble() are tested for conformity with Cokus, which means they provide sufficient randomness. The other methods should yet be used with caution, esp. if long random sequences are to be generated (Monte Carlo simulation etc.).

TODO: Esp. next(int) needs to be tested against randomness criteria; suspected Markov property seen in nextBoolean(). As point of approach, randDouble() and next() use the original Cokus algorithm and can be used as a reference to test randomness against the nextDouble() and nextInt() method that use the scaling mechanism of Random in connection with Cokus's next(int) as a random number generator.

Author:

heinrich

See Also:

Serialized Form

Field Summary

static long	DEFAULTSEED
static long	K a magic constant
double	lastRand
static int	M a period parameter
static int	N length of state vector

Constructor Summary

CokusRandom()
initialise with standard MT seed, 4357.

CokusRandom(long i)
sets the seed (lower half of long taken)

Method Summary

static void	main(java.lang.String[] args)
int	next() returns the next integer
boolean	nextBoolean()
void	nextBytes(byte[] bytes)
double	nextDouble()
float	nextFloat()
double	nextGaussian()
int	nextInt()
int	nextInt(int n)
long	nextLong()
long	nextUnsignedInt() returns a long in the numerical interval of an unsigned int.
long	nextUnsignedLong()
double	randDouble() returns the next double between 0 and 1.
int	reload() reload the random number buffer
void	setSeed(long seed) Note: only lower half of seed is used.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULTSEED

public static final long DEFAULTSEED

See Also:

Constant Field Values

N

public static int N

length of state vector

M

public static int M

a period parameter

K

public static long K

a magic constant

lastRand

public double lastRand

Constructor Detail

CokusRandom

public CokusRandom()

initialise with standard MT seed, 4357.

CokusRandom

public CokusRandom(long i)

sets the seed (lower half of long taken)

Parameters:

i -

Method Detail

main

public static void main(java.lang.String[] args)

next

public int next()

returns the next integer

Returns:

nextUnsignedInt

public long nextUnsignedInt()

returns a long in the numerical interval of an unsigned int.

Returns:

randDouble

public double randDouble()

returns the next double between 0 and 1.

Returns:

setSeed

public void setSeed(long seed)

Note: only lower half of seed is used.

Overrides:

setSeed in class java.util.Random

reload

public int reload()

reload the random number buffer

Returns:

nextDouble

public double nextDouble()

Overrides:

nextDouble in class java.util.Random

nextBoolean

public boolean nextBoolean()

Overrides:

nextBoolean in class java.util.Random

nextFloat

public float nextFloat()

Overrides:

nextFloat in class java.util.Random

nextGaussian

public double nextGaussian()

Overrides:

nextGaussian in class java.util.Random

nextInt

public int nextInt()

Overrides:

nextInt in class java.util.Random

nextUnsignedLong

public long nextUnsignedLong()

nextLong

public long nextLong()

Overrides:

nextLong in class java.util.Random

nextBytes

public void nextBytes(byte[] bytes)

Overrides:

nextBytes in class java.util.Random

nextInt

public int nextInt(int n)

Overrides:

nextInt in class java.util.Random