org.apache.commons.math.distribution
Class ChiSquaredDistributionImpl

java.lang.Object
  extended by org.apache.commons.math.distribution.AbstractDistribution
      extended by org.apache.commons.math.distribution.AbstractContinuousDistribution
          extended by org.apache.commons.math.distribution.ChiSquaredDistributionImpl
All Implemented Interfaces:
java.io.Serializable, ChiSquaredDistribution, ContinuousDistribution, Distribution

public class ChiSquaredDistributionImpl
extends AbstractContinuousDistribution
implements ChiSquaredDistribution, java.io.Serializable

The default implementation of ChiSquaredDistribution

See Also:
Serialized Form

Constructor Summary
ChiSquaredDistributionImpl(double degreesOfFreedom)
          Create a Chi-Squared distribution with the given degrees of freedom.
 
Method Summary
 double cumulativeProbability(double x)
          For this disbution, X, this method returns P(X < x).
 double getDegreesOfFreedom()
          Access the degrees of freedom.
 double inverseCumulativeProbability(double p)
          For this distribution, X, this method returns the critical point x, such that P(X < x) = p.
 void setDegreesOfFreedom(double degreesOfFreedom)
          Modify the degrees of freedom.
 
Methods inherited from class org.apache.commons.math.distribution.AbstractDistribution
cumulativeProbability
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface org.apache.commons.math.distribution.Distribution
cumulativeProbability
 

Constructor Detail

ChiSquaredDistributionImpl

public ChiSquaredDistributionImpl(double degreesOfFreedom)
Create a Chi-Squared distribution with the given degrees of freedom.

Parameters:
degreesOfFreedom - degrees of freedom.
Method Detail

setDegreesOfFreedom

public void setDegreesOfFreedom(double degreesOfFreedom)
Modify the degrees of freedom.

Specified by:
setDegreesOfFreedom in interface ChiSquaredDistribution
Parameters:
degreesOfFreedom - the new degrees of freedom.

getDegreesOfFreedom

public double getDegreesOfFreedom()
Access the degrees of freedom.

Specified by:
getDegreesOfFreedom in interface ChiSquaredDistribution
Returns:
the degrees of freedom.

cumulativeProbability

public double cumulativeProbability(double x)
                             throws MathException
For this disbution, X, this method returns P(X < x).

Specified by:
cumulativeProbability in interface Distribution
Parameters:
x - the value at which the CDF is evaluated.
Returns:
CDF for this distribution.
Throws:
MathException - if the cumulative probability can not be computed due to convergence or other numerical errors.

inverseCumulativeProbability

public double inverseCumulativeProbability(double p)
                                    throws MathException
For this distribution, X, this method returns the critical point x, such that P(X < x) = p.

Returns 0 for p=0 and Double.POSITIVE_INFINITY for p=1.

Specified by:
inverseCumulativeProbability in interface ContinuousDistribution
Overrides:
inverseCumulativeProbability in class AbstractContinuousDistribution
Parameters:
p - the desired probability
Returns:
x, such that P(X < x) = p
Throws:
MathException - if the inverse cumulative probability can not be computed due to convergence or other numerical errors.
java.lang.IllegalArgumentException - if p is not a valid probability.


jHepWork 1.1 (C) Chekanov