NegativeBinomial

java.lang.Object

sim.util.distribution.AbstractDistribution

sim.util.distribution.AbstractDiscreteDistribution

sim.util.distribution.NegativeBinomial

All Implemented Interfaces:: Serializable

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.

See Also:

Field Summary

Fields

Modifier and Type

Field

Description

protected Gamma

gamma

protected int

n

protected double

p

protected Poisson

poisson

Fields inherited from class sim.util.distribution.AbstractDistribution
randomGenerator
Constructor Summary

Constructors

Constructor

Description

NegativeBinomial(int n, double p, MersenneTwisterFast randomGenerator)

Constructs a Negative Binomial distribution.
Method Summary

Modifier and Type

Method

Description

double

cdf(int k)

Returns the cumulative distribution function.

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.

String

toString()

Returns a String representation of the receiver.

Methods inherited from class sim.util.distribution.AbstractDiscreteDistribution
nextDouble

Methods inherited from class sim.util.distribution.AbstractDistribution
apply, apply, getRandomGenerator, setRandomGenerator

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details
- n
  
  protected int n
- p
  
  protected double p
- gamma
  
  protected Gamma gamma
- poisson
  
  protected Poisson poisson
Constructor Details
- NegativeBinomial
  
  public NegativeBinomial(int n, double p, MersenneTwisterFast 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 Details
- cdf
  
  public double cdf(int k)
  
  Returns the cumulative distribution function.
- 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.
- toString
  
  public String toString()
  
  Returns a String representation of the receiver.
  
  Overrides:
  
  toString in class Object