Package cern.jet.random

Class NegativeBinomial

java.lang.Object

cern.colt.PersistentObject

cern.jet.random.AbstractDistribution

cern.jet.random.AbstractDiscreteDistribution

cern.jet.random.NegativeBinomial

All Implemented Interfaces:

DoubleFunction, IntFunction, java.io.Serializable, java.lang.Cloneable

public class NegativeBinomial
extends AbstractDiscreteDistribution

Negative Binomial distribution; See the math definition.

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.

Implementation: High performance implementation. Compound method.

This is a port of nbp.c from the C-RAND / WIN-RAND library. C-RAND's implementation, in turn, is based upon

J.H. Ahrens, U. Dieter (1974): Computer methods for sampling from gamma, beta, Poisson and binomial distributions, Computing 12, 223--246.

Version:

1.0, 09/24/99

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected Gamma	gamma
protected int	n
protected double	p
protected Poisson	poisson
protected static NegativeBinomial	shared

Fields inherited from class cern.jet.random.AbstractDistribution

randomGenerator

Fields inherited from class cern.colt.PersistentObject

serialVersionUID

Constructor Summary

Constructors

Constructor	Description
NegativeBinomial(int n, double p, RandomEngine randomGenerator)	Constructs a Negative Binomial distribution.

Method Summary

Modifier and Type	Method	Description
double	cdf(int k)	Returns the cumulative distribution function.
java.lang.Object	clone()	Returns a deep copy of the receiver; the copy will produce identical sequences.
int	nextInt()	Returns a random number from the distribution.
int	nextInt(int n, double p)	Returns a random number from the distribution; bypasses the internal state.
double	pdf(int k)	Returns the probability distribution function.
void	setNandP(int n, double p)	Sets the parameters number of trials and the probability of success.
static int	staticNextInt(int n, double p)	Returns a random number from the distribution with the given parameters n and p.
java.lang.String	toString()	Returns a String representation of the receiver.
private static void	xstaticSetRandomGenerator(RandomEngine randomGenerator)	Sets the uniform random number generated shared by all static methods.

Methods inherited from class cern.jet.random.AbstractDiscreteDistribution

nextDouble

Methods inherited from class cern.jet.random.AbstractDistribution

apply, apply, getRandomGenerator, makeDefaultGenerator, setRandomGenerator

Methods inherited from class java.lang.Object

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

Field Detail

n

protected int n

p

protected double p

gamma

protected Gamma gamma

poisson

protected Poisson poisson

shared

protected static NegativeBinomial shared

Constructor Detail

NegativeBinomial

public NegativeBinomial(int n,
                        double p,
                        RandomEngine randomGenerator)

Constructs a Negative Binomial distribution. Example: n=1, p=0.5.

Parameters:

n - the number of trials.

p - the probability of success.

randomGenerator - a uniform random number generator.

Method Detail

cdf

public double cdf(int k)

Returns the cumulative distribution function.

clone

public java.lang.Object clone()

Returns a deep copy of the receiver; the copy will produce identical sequences. After this call has returned, the copy and the receiver have equal but separate state.

Overrides:

clone in class AbstractDistribution

Returns:

a copy of the receiver.

nextInt

public int nextInt()

Returns a random number from the distribution.

Specified by:

nextInt in class AbstractDiscreteDistribution

nextInt

public int nextInt(int n,
                   double p)

Returns a random number from the distribution; bypasses the internal state.

pdf

public double pdf(int k)

Returns the probability distribution function.

setNandP

public void setNandP(int n,
                     double p)

Sets the parameters number of trials and the probability of success.

Parameters:

n - the number of trials

p - the probability of success.

staticNextInt

public static int staticNextInt(int n,
                                double p)

Returns a random number from the distribution with the given parameters n and p.

Parameters:

n - the number of trials

p - the probability of success.

toString

public java.lang.String toString()

Returns a String representation of the receiver.

Overrides:

toString in class java.lang.Object

xstaticSetRandomGenerator

private static void xstaticSetRandomGenerator(RandomEngine randomGenerator)

Sets the uniform random number generated shared by all static methods.

Parameters:

randomGenerator - the new uniform random number generator to be shared.