sim.util.distribution
Class Exponential

java.lang.Object
  sim.util.distribution.AbstractDistribution
      sim.util.distribution.AbstractContinousDistribution
          sim.util.distribution.Exponential

All Implemented Interfaces:

java.io.Serializable

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.

See Also:

Serialized Form

Field Summary

protected double

lambda

Fields inherited from class sim.util.distribution.AbstractDistribution

randomGenerator

Constructor Summary

Exponential(double lambda, MersenneTwisterFast randomGenerator)
Constructs a Negative Exponential distribution.

Method Summary

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.
java.lang.String	toString() Returns a String representation of the receiver.

Methods inherited from class sim.util.distribution.AbstractDistribution

apply, apply, getRandomGenerator, nextInt, setRandomGenerator

Methods inherited from class java.lang.Object

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

Field Detail

lambda

protected double lambda

Constructor Detail

Exponential

public Exponential(double lambda,
                   MersenneTwisterFast 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.

toString

public java.lang.String toString()

Returns a String representation of the receiver.

Overrides:

toString in class java.lang.Object