cern.jet.random

Class Exponential

java.lang.Object

cern.colt.PersistentObject

cern.jet.random.AbstractDistribution

cern.jet.random.AbstractContinousDistribution

cern.jet.random.Exponential

All Implemented Interfaces:

DoubleFunction, IntFunction, Serializable, Cloneable

public class Exponential
extends AbstractContinousDistribution

Exponential Distribution (aka Negative Exponential Distribution); See the math definition animated definition.

p(x) = lambda*exp(-x*lambda) for x >= 0, lambda > 0.

Instance methods operate on a user supplied uniform random number generator; they are unsynchronized.

Static methods operate on a default uniform random number generator; they are synchronized.

Version:

1.0, 09/24/99

Author:

wolfgang.hoschek@cern.ch

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected double	lambda
protected static Exponential	shared

Fields inherited from class cern.jet.random.AbstractDistribution

randomGenerator

Fields inherited from class cern.colt.PersistentObject

serialVersionUID

Constructor Summary

Constructors

Constructor and Description
Exponential(double lambda, RandomEngine randomGenerator) Constructs a Negative Exponential distribution.

Method Summary

Methods

Modifier and Type	Method and Description
double	cdf(double x) Returns the cumulative distribution function.
double	nextDouble() Returns a random number from the distribution.
double	nextDouble(double lambda) Returns a random number from the distribution; bypasses the internal state.
double	pdf(double x) Returns the probability distribution function.
void	setState(double lambda) Sets the mean.
static double	staticNextDouble(double lambda) Returns a random number from the distribution with the given lambda.
String	toString() Returns a String representation of the receiver.

Methods inherited from class cern.jet.random.AbstractDistribution

apply, apply, clone, getRandomGenerator, makeDefaultGenerator, nextInt, setRandomGenerator

Methods inherited from class java.lang.Object

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

Field Detail

lambda

protected double lambda

shared

protected static Exponential shared

Constructor Detail

Exponential

public Exponential(double lambda,
           RandomEngine randomGenerator)

Constructs a Negative Exponential distribution.

Method Detail

cdf

public double cdf(double x)

Returns the cumulative distribution function.

nextDouble

public double nextDouble()

Returns a random number from the distribution.

Specified by:

nextDouble in class AbstractDistribution

nextDouble

public double nextDouble(double lambda)

Returns a random number from the distribution; bypasses the internal state.

pdf

public double pdf(double x)

Returns the probability distribution function.

setState

public void setState(double lambda)

Sets the mean.

staticNextDouble

public static double staticNextDouble(double lambda)

Returns a random number from the distribution with the given lambda.

toString

public String toString()

Returns a String representation of the receiver.

Overrides:

toString in class Object