gov.sandia.cognition.util

Class DoubleReuseRandom

java.lang.Object

java.util.Random

gov.sandia.cognition.util.DoubleReuseRandom

All Implemented Interfaces:

java.io.Serializable

public class DoubleReuseRandom
extends java.util.Random

An extension of java.util.Random that builds a list of random doubles and then serves up the random values from the array, returning to the beginning when the end is reached. This class Only nextDouble() will return these repeated sequences of random numbers. All other types should work according to the java.util.Random implementation. This class can be helpful when a program is experiencing slowdown from frequently calling Random.nextDouble(). This class decreases the mathematical purity of the random number sequence (as the sequence is reused). Recommendations: 1) make sure the length of the array is different from the number of iterations of other loops in the program. This will help avoid situations where the same numbers are used in the same context of the loop. 2) make the length of the array large enough to guarantee sufficient coverage of the random number sequence (an array of length 10 would likely have gaps in the range of numbers)

Since:

3.4.2

Author:

Sean Crosby

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
DoubleReuseRandom(int arrayLen) Creates DoubleReuseRandom with the given parameters
DoubleReuseRandom(int arrayLen, long seed) Creates DoubleReuseRandom with the given parameters

Method Summary

Modifier and Type	Method and Description
int	getArrayLen() Gets the length of the array of doubles
double	nextDouble() Returns the next double from the array

Methods inherited from class java.util.Random

doubles, doubles, doubles, doubles, ints, ints, ints, ints, longs, longs, longs, longs, next, nextBoolean, nextBytes, nextFloat, nextGaussian, nextInt, nextInt, nextLong, setSeed

Methods inherited from class java.lang.Object

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

Constructor Detail

DoubleReuseRandom

public DoubleReuseRandom(int arrayLen)

Creates DoubleReuseRandom with the given parameters

Parameters:

arrayLen - the number of doubles to generate and cycle over

DoubleReuseRandom

public DoubleReuseRandom(int arrayLen,
                         long seed)

Creates DoubleReuseRandom with the given parameters

Parameters:

arrayLen - the number of doubles to generate and cycle over

seed - the seed passed to the underlying Random class

Method Detail

getArrayLen

public int getArrayLen()

Gets the length of the array of doubles

Returns:

length of the array of doubles

nextDouble

public double nextDouble()

Returns the next double from the array

Overrides:

nextDouble in class java.util.Random

Returns:

random double