Package jsl.utilities.distributions

Class Constant

java.lang.Object

jsl.utilities.distributions.Distribution

jsl.utilities.distributions.Constant

All Implemented Interfaces:

ControllableIfc, CDFIfc, DiscreteDistributionIfc, DistributionFunctionIfc, DistributionIfc, InverseCDFIfc, MeanIfc, PMFIfc, VarianceIfc, GetNameIfc, IdentityIfc, NewInstanceIfc, ParametersIfc, GetRVariableIfc

Direct Known Subclasses:

VConstant

public class Constant
extends Distribution
implements DiscreteDistributionIfc, GetRVariableIfc

Constructs a degenerate distribution with all probability at the provided point. Once made the value of the constant cannot be changed.

Nested Class Summary

Nested classes/interfaces inherited from class jsl.utilities.distributions.Distribution

Distribution.RandomControls

Field Summary

Fields

Modifier and Type	Field	Description
protected double	myValue
static Constant	ONE	A constant to represent one for sharing
static Constant	POSITIVE_INFINITY	A constant to represent positive infinity for sharing
static Constant	TWO	A constant to represent two for sharing
static Constant	ZERO	A constant to represent zero for sharing

Fields inherited from class jsl.utilities.distributions.Distribution

myId, myName

Constructor Summary

Constructors

Constructor	Description
Constant(double value)	Construct a constant using the supplied value
Constant(double[] parameters)
Constant(double value, java.lang.String name)	Construct a constant using the supplied value

Method Summary

Modifier and Type	Method	Description
double	cdf(double x)	Returns the F(x) = Pr{X <= x} where F represents the cumulative distribution function
double	getMean()	Returns the mean or expected value of a distribution
double[]	getParameters()	Gets the parameters
RVariableIfc	getRandomVariable(RNStreamIfc rng)
double	getVariance()	Returns the variance of the distribution if defined
double	invCDF(double p)	Provides the inverse cumulative distribution function for the distribution While closed form solutions for the inverse cdf may not exist, numerical search methods can be used to solve F(X) = U.
Constant	newInstance()	Returns a new instance
double	pmf(double x)	Returns the f(x) where f represents the probability mass function for the distribution.
void	setParameters(double[] parameters)	Sets the parameters

Methods inherited from class jsl.utilities.distributions.Distribution

getControls, getId, getName, getStandardDeviation, inverseContinuousCDFViaBisection, inverseContinuousCDFViaBisection, inverseDiscreteCDFViaSearchUp, setControls, setId, setName, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface jsl.utilities.distributions.CDFIfc

cdf, complementaryCDF

Methods inherited from interface jsl.utilities.random.rvariable.GetRVariableIfc

getRandomVariable, getRandomVariable

Field Detail

ZERO

public static final Constant ZERO

A constant to represent zero for sharing

ONE

public static final Constant ONE

A constant to represent one for sharing

TWO

public static final Constant TWO

A constant to represent two for sharing

POSITIVE_INFINITY

public static final Constant POSITIVE_INFINITY

A constant to represent positive infinity for sharing

myValue

protected double myValue

Constructor Detail

Constant

public Constant(double value)

Construct a constant using the supplied value

Parameters:

value - the value for the constant

Constant

public Constant(double[] parameters)

Parameters:

parameters - the parameter[0] is the value

Constant

public Constant(double value,
                java.lang.String name)

Construct a constant using the supplied value

Parameters:

value - the value for the constant

name - a string name/label

Method Detail

newInstance

public Constant newInstance()

Description copied from interface: NewInstanceIfc

Returns a new instance

Specified by:

newInstance in interface NewInstanceIfc

Specified by:

newInstance in class Distribution

Returns:

the new instance

setParameters

public void setParameters(double[] parameters)

Description copied from interface: ParametersIfc

Sets the parameters

Specified by:

setParameters in interface ParametersIfc

Parameters:

parameters - an array of doubles representing the parameters

getParameters

public final double[] getParameters()

Description copied from interface: ParametersIfc

Gets the parameters

Specified by:

getParameters in interface ParametersIfc

Returns:

Returns an array of the parameters

pmf

public final double pmf(double x)

Description copied from interface: PMFIfc

Returns the f(x) where f represents the probability mass function for the distribution.

Specified by:

pmf in interface PMFIfc

Parameters:

x - a double representing the value to be evaluated

Returns:

f(x) the P(X=x)

cdf

public final double cdf(double x)

Description copied from interface: CDFIfc

Returns the F(x) = Pr{X <= x} where F represents the cumulative distribution function

Specified by:

cdf in interface CDFIfc

Parameters:

x - a double representing the upper limit

Returns:

a double representing the probability

getMean

public final double getMean()

Description copied from interface: MeanIfc

Returns the mean or expected value of a distribution

Specified by:

getMean in interface MeanIfc

Returns:

double the mean or expected value for the distribution

getVariance

public final double getVariance()

Description copied from interface: VarianceIfc

Returns the variance of the distribution if defined

Specified by:

getVariance in interface VarianceIfc

Returns:

double the variance of the random variable

invCDF

public final double invCDF(double p)

Description copied from interface: InverseCDFIfc

Provides the inverse cumulative distribution function for the distribution While closed form solutions for the inverse cdf may not exist, numerical search methods can be used to solve F(X) = U.

Specified by:

invCDF in interface InverseCDFIfc

Parameters:

p - The probability to be evaluated for the inverse, p must be [0,1] or an IllegalArgumentException is thrown

Returns:

The inverse cdf evaluated at the supplied probability

getRandomVariable

public final RVariableIfc getRandomVariable(RNStreamIfc rng)

Specified by:

getRandomVariable in interface GetRVariableIfc

Overrides:

getRandomVariable in class Distribution

Parameters:

rng - the stream to use

Returns:

a random variable