edu.udo.cs.yale.tools
Class RandomGenerator

java.lang.Object
  java.util.Random
      edu.udo.cs.yale.tools.RandomGenerator

All Implemented Interfaces:

java.io.Serializable

public class RandomGenerator
extends java.util.Random

The global random number generator. This should be used for all random purposes of Yale to ensure that two runs of the same experiment provide the same results.

Version:

$Id: RandomGenerator.java,v 2.19 2006/08/03 14:39:31 ingomierswa Exp $

Author:

Ralf Klinkenberg, Ingo Mierswa

See Also:

Serialized Form

Field Summary

private static java.lang.String	ALPHABET Use this alphabet for random String creation.
private static RandomGenerator	globalRandomGenerator Global random number generator using the random number generator seed specified for the root operator (ExperimentOperator).
private static long	serialVersionUID

Constructor Summary

private	RandomGenerator() Initializes the random number generator without a seed.
	RandomGenerator(long seed) Initializes the random number generator with the given seed

Method Summary

static RandomGenerator	getGlobalRandomGenerator() Returns the global random number generator.
static RandomGenerator	getRandomGenerator(int seed) Returns the global random number generator if the seed is negative and a new RandomGenerator with the given seed if the seed is positive or zero.
static void	init(Experiment experiment) Instantiates the global random number generator and initializes it with the random number generator seed specified in the global section of the configuration file.
double	nextDoubleInRange(double lowerBound, double upperBound) Returns the next pseudorandom, uniformly distributed double value between lowerBound and upperBound from this random number generator's sequence (exclusive of the interval endpoint values).
int	nextIntInRange(int lowerBound, int upperBound) Returns the next pseudorandom, uniformly distributed int value between lowerBound and upperBound from this random number generator's sequence (exclusive of the interval endpoint values).
long	nextLongInRange(long lowerBound, long upperBound) returns the next pseudorandom, uniformly distributed long value between lowerBound and upperBound from this random number generator's sequence (exclusive of the interval endpoint values).
java.lang.String	nextString(int length) Returns a random String of the given length.
int	randomIndex(double[] probs) Returns a randomly selected integer between 0 and the length of the given array.

Methods inherited from class java.util.Random

next, nextBoolean, nextBytes, nextDouble, nextFloat, nextGaussian, nextInt, nextInt, nextLong, setSeed

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

See Also:

Constant Field Values

ALPHABET

private static final java.lang.String ALPHABET

Use this alphabet for random String creation.

See Also:

Constant Field Values

globalRandomGenerator

private static RandomGenerator globalRandomGenerator

Global random number generator using the random number generator seed specified for the root operator (ExperimentOperator).

Constructor Detail

RandomGenerator

private RandomGenerator()

Initializes the random number generator without a seed.

RandomGenerator

public RandomGenerator(long seed)

Initializes the random number generator with the given seed

Method Detail

getGlobalRandomGenerator

public static RandomGenerator getGlobalRandomGenerator()

Returns the global random number generator.

getRandomGenerator

public static RandomGenerator getRandomGenerator(int seed)

Returns the global random number generator if the seed is negative and a new RandomGenerator with the given seed if the seed is positive or zero. This way is is possible to allow for local random seeds. Operators like learners or validation operators should definitely make use of such a local random generator.

init

public static void init(Experiment experiment)

Instantiates the global random number generator and initializes it with the random number generator seed specified in the global section of the configuration file. Should be invoked before the experiment starts.

nextDoubleInRange

public double nextDoubleInRange(double lowerBound,
                                double upperBound)

Returns the next pseudorandom, uniformly distributed double value between lowerBound and upperBound from this random number generator's sequence (exclusive of the interval endpoint values).

nextLongInRange

public long nextLongInRange(long lowerBound,
                            long upperBound)

returns the next pseudorandom, uniformly distributed long value between lowerBound and upperBound from this random number generator's sequence (exclusive of the interval endpoint values).

nextIntInRange

public int nextIntInRange(int lowerBound,
                          int upperBound)

Returns the next pseudorandom, uniformly distributed int value between lowerBound and upperBound from this random number generator's sequence (exclusive of the interval endpoint values).

nextString

public java.lang.String nextString(int length)

Returns a random String of the given length.

randomIndex

public int randomIndex(double[] probs)

Returns a randomly selected integer between 0 and the length of the given array. Uses the given probabilities to determine the index, all values in this array must sum up to 1.