de.lmu.ifi.dbs.elki.math.statistics.distribution

Class ChiDistribution

java.lang.Object

de.lmu.ifi.dbs.elki.math.statistics.distribution.AbstractDistribution

de.lmu.ifi.dbs.elki.math.statistics.distribution.ChiDistribution

All Implemented Interfaces:

Distribution

public class ChiDistribution
extends AbstractDistribution

Chi distribution.

Author:

Erich Schubert

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ChiDistribution.Parameterizer Parameterization class

Field Summary

Fields

Modifier and Type	Field and Description
private ChiSquaredDistribution	chisq Chi squared distribution (for random generation)
private double	dof Degrees of freedom.

Fields inherited from class de.lmu.ifi.dbs.elki.math.statistics.distribution.AbstractDistribution

random

Constructor Summary

Constructors

Constructor and Description
ChiDistribution(double dof) Constructor.
ChiDistribution(double dof, Random random) Constructor.
ChiDistribution(double dof, RandomFactory random) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
double	cdf(double val) Return the cumulative density function at the given value.
static double	cdf(double val, double dof) Cumulative density function.
double	nextRandom() Generate a new random value
double	pdf(double val) Return the density of an existing value
static double	pdf(double val, double dof) PDF function
double	quantile(double val) Quantile aka probit (for normal) aka inverse CDF (invcdf, cdf^-1) function.
String	toString() Describe the distribution

Methods inherited from class java.lang.Object

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

Field Detail

dof

private double dof

Degrees of freedom. Usually integer.

chisq

private ChiSquaredDistribution chisq

Chi squared distribution (for random generation)

Constructor Detail

ChiDistribution

public ChiDistribution(double dof)

Constructor.

Parameters:

dof - Degrees of freedom. Usually integer.

ChiDistribution

public ChiDistribution(double dof,
               Random random)

Constructor.

Parameters:

dof - Degrees of freedom. Usually integer.

random - Random number generator.

ChiDistribution

public ChiDistribution(double dof,
               RandomFactory random)

Constructor.

Parameters:

dof - Degrees of freedom. Usually integer.

random - Random number generator.

Method Detail

nextRandom

public double nextRandom()

Description copied from interface: Distribution

Generate a new random value

Specified by:

nextRandom in interface Distribution

Overrides:

nextRandom in class AbstractDistribution

Returns:

new random value

pdf

public double pdf(double val)

Description copied from interface: Distribution

Return the density of an existing value

Parameters:

val - existing value

Returns:

distribution density

pdf

public static double pdf(double val,
         double dof)

PDF function

Parameters:

val - Value

dof - Degrees of freedom

Returns:

Pdf value

cdf

public double cdf(double val)

Description copied from interface: Distribution

Return the cumulative density function at the given value.

Parameters:

val - existing value

Returns:

cumulative density

cdf

public static double cdf(double val,
         double dof)

Cumulative density function.

Parameters:

val - Value

dof - Degrees of freedom.

Returns:

CDF value

quantile

public double quantile(double val)

Description copied from interface: Distribution

Quantile aka probit (for normal) aka inverse CDF (invcdf, cdf^-1) function.

Parameters:

val - Quantile to find

Returns:

Quantile position

toString

public String toString()

Description copied from interface: Distribution

Describe the distribution

Specified by:

toString in interface Distribution

Overrides:

toString in class Object

Returns:

description