blog.distrib
Class NegativeBinomial

java.lang.Object
  blog.AbstractCondProbDistrib
      blog.distrib.NegativeBinomial

All Implemented Interfaces:

CondProbDistrib

public class NegativeBinomial
extends AbstractCondProbDistrib

A Negative Binomial distribution with parameters k (number of successes) and p (probability of a success at a given trial). If k is an integer, this is also called the Pascal distribution. The distribution is defined (in discrete terms) as the number of failures before k successes.

Constructor Summary

NegativeBinomial(java.util.List params)
Creates a new instance of the NegativeBinomial with parameters k and p.

Method Summary

double	getLogProb(java.util.List args, java.lang.Object value) Returns the log of the probability of n failures in this distribution.
double	getProb(java.util.List args, java.lang.Object value) Returns the probability of n failures under this distribution.
java.lang.Object	sampleVal(java.util.List args, Type childType) Returns a double sampled according to this distribution.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

NegativeBinomial

public NegativeBinomial(java.util.List params)

Creates a new instance of the NegativeBinomial with parameters k and p.

Method Detail

getProb

public double getProb(java.util.List args,
                      java.lang.Object value)

Returns the probability of n failures under this distribution.

getLogProb

public double getLogProb(java.util.List args,
                         java.lang.Object value)

Returns the log of the probability of n failures in this distribution.

Specified by:

getLogProb in interface CondProbDistrib

Overrides:

getLogProb in class AbstractCondProbDistrib

sampleVal

public java.lang.Object sampleVal(java.util.List args,
                                  Type childType)

Returns a double sampled according to this distribution. Takes time O(GammaDistrib.sampleVal() + Poisson.sampleVal()). (Reference: A Guide To Simulation, 2nd Ed. Bratley, Paul, Bennett L. Fox and Linus E. Schrage.)

toString

public java.lang.String toString()

Overrides:

toString in class AbstractCondProbDistrib