Class Zipf

java.lang.Object

random.AbstractDistribution

random.discrete.DiscreteDistribution

random.discrete.Zipf

All Implemented Interfaces:

StorableDistribution

public class Zipf
extends DiscreteDistribution

Zipf distribution, used to model popularity skews in the JMT simulation engine.

Field Summary

Fields inherited from class DiscreteDistribution

cached, CDFList, CDFListCalculated

Fields inherited from class AbstractDistribution

engine

Constructor Summary

Constructors

Constructor	Description
Zipf()
Zipf(double alpha, int numberOfElements)
Zipf(Double alpha, Integer numberOfElements)
Zipf(Integer numberOfElements, Double alpha)

Method Summary

Modifier and Type	Method	Description
double	cdf(int x)
double	cdf(int x, Parameter p)	obtain the cumulative distribution from the distribution
int	getlower()
int	getUpper()
int	nextRand()	These functions are used to direct initialize the Discrete Distribution.
int	nextRand(Parameter p)	Generate random variables that follow an probability distribution
void	outdated()	Set all cache flag false, call it when parameters changed.
double	pmf(int x)
double	pmf(int x, Parameter p)	obtain the probability distribution from the distribution
double	theorMean()
double	theorMean(Parameter p)	Calculate the Mean value from the parameter of the distribution
double	theorVariance()
double	theorVariance(Parameter p)	Calculate the Variance from the parameter of the distribution
boolean	updatePar(double alpha, int numberOfElements)
boolean	updatePar(Parameter p)	Sub-class must implement this method to update parameter.

Methods inherited from class DiscreteDistribution

binarySearch, createdCDFList, createdCDFList, inverseTransformSampling

Methods inherited from class AbstractDistribution

setRandomEngine

Methods inherited from class Object

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

Constructor Details

Zipf

public Zipf()

Zipf

public Zipf(double alpha,
 int numberOfElements)
     throws IncorrectDistributionParameterException

Throws:

IncorrectDistributionParameterException

Zipf

public Zipf(Double alpha,
 Integer numberOfElements)
     throws IncorrectDistributionParameterException

Throws:

IncorrectDistributionParameterException

Zipf

public Zipf(Integer numberOfElements,
 Double alpha)
     throws IncorrectDistributionParameterException

Throws:

IncorrectDistributionParameterException

Method Details

updatePar

public boolean updatePar(double alpha,
 int numberOfElements)
                  throws IncorrectDistributionParameterException

Throws:

IncorrectDistributionParameterException

updatePar

public boolean updatePar(Parameter p)
                  throws IncorrectDistributionParameterException

Description copied from class: DiscreteDistribution

Sub-class must implement this method to update parameter.

Specified by:

updatePar in class DiscreteDistribution

Throws:

IncorrectDistributionParameterException

outdated

public void outdated()

Description copied from class: DiscreteDistribution

Set all cache flag false, call it when parameters changed.

Overrides:

outdated in class DiscreteDistribution

getUpper

public int getUpper()

Specified by:

getUpper in class DiscreteDistribution

getlower

public int getlower()

Specified by:

getlower in class DiscreteDistribution

nextRand

public int nextRand()

Description copied from class: DiscreteDistribution

These functions are used to direct initialize the Discrete Distribution. once invoke parameter constructor with the distribution parameter, set cached = true. if not cache the parameter, only method with `Parameter` are available.

Specified by:

nextRand in class DiscreteDistribution

pmf

public double pmf(int x)

Specified by:

pmf in class DiscreteDistribution

cdf

public double cdf(int x)

Specified by:

cdf in class DiscreteDistribution

theorMean

public double theorMean()

Specified by:

theorMean in class DiscreteDistribution

theorVariance

public double theorVariance()

Specified by:

theorVariance in class DiscreteDistribution

nextRand

public int nextRand(Parameter p)
             throws IncorrectDistributionParameterException

Description copied from class: DiscreteDistribution

Generate random variables that follow an probability distribution

Specified by:

nextRand in class DiscreteDistribution

Parameters:

p - parameter of the distribution.

Returns:

int - random variables that follow an probability distribution

Throws:

IncorrectDistributionParameterException

pmf

public double pmf(int x,
 Parameter p)
           throws IncorrectDistributionParameterException

Description copied from class: DiscreteDistribution

obtain the probability distribution from the distribution

Specified by:

pmf in class DiscreteDistribution

Parameters:

x - int - random variable indicating where to evaluate the pmf.

p - parameter of the distribution.

Returns:

double - the probability weight evaluated at x.

Throws:

IncorrectDistributionParameterException

cdf

public double cdf(int x,
 Parameter p)
           throws IncorrectDistributionParameterException

Description copied from class: DiscreteDistribution

obtain the cumulative distribution from the distribution

Specified by:

cdf in class DiscreteDistribution

Parameters:

x - int - random variable indicating where to evaluate the cdf.

p - parameter of the distribution.

Returns:

double - the probability weight cumulated at x.

Throws:

IncorrectDistributionParameterException

theorMean

public double theorMean(Parameter p)
                 throws IncorrectDistributionParameterException

Description copied from class: DiscreteDistribution

Calculate the Mean value from the parameter of the distribution

Specified by:

theorMean in class DiscreteDistribution

Parameters:

p - parameter of the distribution.

Returns:

double - theoretic mean value of the distribution.

Throws:

IncorrectDistributionParameterException

theorVariance

public double theorVariance(Parameter p)
                     throws IncorrectDistributionParameterException

Description copied from class: DiscreteDistribution

Calculate the Variance from the parameter of the distribution

Specified by:

theorVariance in class DiscreteDistribution

Parameters:

p - parameter of the distribution.

Returns:

double - theoretic variance value of the distribution.

Throws:

IncorrectDistributionParameterException