org.lcsim.math.distribution

Class EmpiricalDistribution

java.lang.Object

org.lcsim.math.distribution.EmpiricalDistribution

public class EmpiricalDistribution
extends Object

Generate random numbers according to an empirical distribution provided by the user as an array of positive real numbers. Based on RandomGeneral from CLHEP.

Version:

$Id:

Author:

Norman A. Graf

Field Summary

Fields

Modifier and Type	Field and Description
protected double[]	_cdf
protected int	_interpolationType
private Random	_rand

Constructor Summary

Constructors

Constructor and Description
EmpiricalDistribution(double[] pdf) Create an EmpiricalDistribution from an input array of positive values.

Method Summary

Methods

Modifier and Type	Method and Description
double	nextDouble() Returns a random number from the distribution.
double	pdf(int k) Returns the probability distribution function.
void	setSeed(long seed) Allows the random number generator seed to be set
void	setState(double[] pdf) Creates and normalizes the cumulative probability distribution
String	toString() Returns a String representation of the receiver.

Methods inherited from class java.lang.Object

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

Field Detail

_rand

private Random _rand

_cdf

protected double[] _cdf

_interpolationType

protected int _interpolationType

Constructor Detail

EmpiricalDistribution

public EmpiricalDistribution(double[] pdf)

Create an EmpiricalDistribution from an input array of positive values. The array value i should be thought of as the central value of bin i in an equally binned distribution. The values will be normalized internally. This constructor will return doubles from the usual interval between 0 and 1.

Parameters:

pdf - an array of positive values representing the empirical distribution from which random numbers should be drawn.

Method Detail

setSeed

public void setSeed(long seed)

Allows the random number generator seed to be set

Parameters:

seed -

nextDouble

public double nextDouble()

Returns a random number from the distribution.

Returns:

the next double value drawn from this distribution

pdf

public double pdf(int k)

Returns the probability distribution function.

setState

public void setState(double[] pdf)

Creates and normalizes the cumulative probability distribution

toString

public String toString()

Returns a String representation of the receiver.

Overrides:

toString in class Object