org.jscience.measure.random
Class EcuyerGenerator

java.lang.Object
  org.jscience.measure.random.RandomElement
      org.jscience.measure.random.RandomSeedable
          org.jscience.measure.random.EcuyerGenerator

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, RandomGenerator

public class EcuyerGenerator
extends RandomSeedable
implements java.io.Serializable

Ranecu is an advanced multiplicative linear congruential random number generator with a period of aproximately 10¹⁸. Ranecu is a direct translation from Fortran of the RANECU subroutine published in the paper
F. James, Comp. Phys. Comm. 60 (1990) p 329-344
The algorithm was originally described in
P. L'Ecuyer, Commun. ACM. 1988 (1988) p 742

Source code is available.

See Also:

Serialized Form

Field Summary

static int	DEFSEED1 default iseed1 = 12345
static int	DEFSEED2 default iseed2 = 67890

Constructor Summary

EcuyerGenerator()
Initialize RANECU with the default seeds from James.

EcuyerGenerator(java.util.Date d)

EcuyerGenerator(int s1, int s2)
Initialize RANECU with two specified integer seeds.

EcuyerGenerator(long l)

Method Summary

long	getSeed()
double	nextDouble() Generate a random scalar with null mean and unit standard deviation.
void	nextDouble(double[] d, int n) This is an inline version that returns an array of doubles for speed.

Methods inherited from class org.jscience.measure.random.RandomSeedable

ClockSeed, ClockSeed

Methods inherited from class org.jscience.measure.random.RandomElement

choose, choose, clone, coin, coin, gaussian, gaussian, nextDouble, powlaw, uniform

Methods inherited from class java.lang.Object

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

Field Detail

DEFSEED1

public static int DEFSEED1

default iseed1 = 12345

DEFSEED2

public static int DEFSEED2

default iseed2 = 67890

Constructor Detail

EcuyerGenerator

public EcuyerGenerator()

Initialize RANECU with the default seeds from James.

EcuyerGenerator

public EcuyerGenerator(int s1,
                       int s2)

Initialize RANECU with two specified integer seeds. Use this to introduce repeatable seeds. Equivalent to

Ranecu(s1*(long) Integer.MAX_VALUE)+s2)

Parameters:

s1 - seed integer 1 (MSW)

s2 - seed integer 2 (LSW)

EcuyerGenerator

public EcuyerGenerator(long l)

EcuyerGenerator

public EcuyerGenerator(java.util.Date d)

Method Detail

nextDouble

public final double nextDouble()

Description copied from interface: RandomGenerator

Generate a random scalar with null mean and unit standard deviation.

This method does not specify the shape of the distribution, it is the implementing class that provides it. The only contract here is to generate numbers with null mean and unit standard deviation.

Specified by:

nextDouble in interface RandomGenerator

Returns:

a random scalar

See Also:

RandomElement.nextDouble(double[], int)

nextDouble

public final void nextDouble(double[] d,
                             int n)

This is an inline version that returns an array of doubles for speed.

Overrides:

nextDouble in class RandomElement

Parameters:

d - array to be filled with doubles

n - number of doubles to generate

getSeed

public long getSeed()

Returns:

the current generator state as a long. Can be used to restart the generator where one left off.