org.encog.mathutil.randomize.generate

Class LinearCongruentialRandom

java.lang.Object

org.encog.mathutil.randomize.generate.AbstractGenerateRandom

org.encog.mathutil.randomize.generate.AbstractBoxMuller

org.encog.mathutil.randomize.generate.LinearCongruentialRandom

All Implemented Interfaces:

GenerateRandom

public class LinearCongruentialRandom
extends AbstractBoxMuller

A Linear Congruential random number generator. A Linear Congruential Generator (LCG) yields a sequence of randomized numbers calculated with a linear equation. The method represents one of the oldest and best-known pseudorandom number generator algorithms. Most programming languages use this technique. http://en.wikipedia.org/wiki/Linear_congruential_generator/ Donald Knuth, The Art of Computer Programming, Volume 3, Section 3.2.1

Field Summary

Fields

Modifier and Type	Field and Description
static long	DEFAULT_INC Default inc.
static long	DEFAULT_MOD1 First part of default mod.
static long	DEFAULT_MOD2 Second part of default mod.
static long	DEFAULT_MULT Default mult.
static long	MAX_RAND The maximum rand number that the standard GCC based LCG will generate.

Fields inherited from class org.encog.mathutil.randomize.generate.AbstractBoxMuller

MU

Constructor Summary

Constructors

Constructor and Description
LinearCongruentialRandom() Constructor to use a seed equal to system time.
LinearCongruentialRandom(long theSeed) Construct the default LCG.
LinearCongruentialRandom(long theModulus, long theMultiplier, long theIncrement, long theSeed) Create a LCG with the specified modulus, multiplier and increment.

Method Summary

Modifier and Type	Method and Description
long	getIncrement()
long	getModulus()
long	getMultiplier()
long	getSeed()
boolean	nextBoolean()
double	nextDouble()
float	nextFloat()
int	nextInt()
long	nextLong()

Methods inherited from class org.encog.mathutil.randomize.generate.AbstractBoxMuller

nextGaussian

Methods inherited from class org.encog.mathutil.randomize.generate.AbstractGenerateRandom

nextDouble, nextDouble, nextInt, nextInt

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_MOD1

public static final long DEFAULT_MOD1

First part of default mod.

See Also:

Constant Field Values

DEFAULT_MOD2

public static final long DEFAULT_MOD2

Second part of default mod.

See Also:

Constant Field Values

DEFAULT_MULT

public static final long DEFAULT_MULT

Default mult.

See Also:

Constant Field Values

DEFAULT_INC

public static final long DEFAULT_INC

Default inc.

See Also:

Constant Field Values

MAX_RAND

public static final long MAX_RAND

The maximum rand number that the standard GCC based LCG will generate.

See Also:

Constant Field Values

Constructor Detail

LinearCongruentialRandom

public LinearCongruentialRandom(long theSeed)

Construct the default LCG. You need only specify a seed.

Parameters:

theSeed - The seed to use.

LinearCongruentialRandom

public LinearCongruentialRandom()

Constructor to use a seed equal to system time.

LinearCongruentialRandom

public LinearCongruentialRandom(long theModulus,
                                long theMultiplier,
                                long theIncrement,
                                long theSeed)

Create a LCG with the specified modulus, multiplier and increment. Unless you REALLY KNOW WHAT YOU ARE DOING, just use the constructor that just takes a seed. It will set these values to the same as set by the GCC C compiler. Setting these values wrong can create fairly useless random numbers.

Parameters:

theModulus - The modulus for the LCG algorithm.

theMultiplier - The multiplier for the LCG algorithm.

theIncrement - The increment for the LCG algorithm.

theSeed - The seed for the LCG algorithm. Using the same seed will give the same random number sequence each time, whether in Java or DotNet.

Method Detail

getIncrement

public final long getIncrement()

Returns:

The LCG increment.

getModulus

public final long getModulus()

Returns:

The LCG modulus.

getMultiplier

public final long getMultiplier()

Returns:

The LCG multiplier.

getSeed

public final long getSeed()

Returns:

The current seed. Set to a constant to start, thereafter the previously generated random number.

nextDouble

public final double nextDouble()

Returns:

The next random number as a double between 0 and 1.

nextLong

public final long nextLong()

Returns:

The next random number as a long between 0 and MAX_RAND.

nextBoolean

public boolean nextBoolean()

Returns:

The next random boolean.

nextFloat

public float nextFloat()

Returns:

The next random floating point.

nextInt

public int nextInt()

Returns:

The next random integer.