gov.sandia.cognition.statistics.distribution

Class GammaDistribution.PDF

java.lang.Object

gov.sandia.cognition.util.AbstractCloneableSerializable

gov.sandia.cognition.statistics.AbstractDistribution<NumberType>

gov.sandia.cognition.statistics.AbstractClosedFormUnivariateDistribution<java.lang.Double>

gov.sandia.cognition.statistics.AbstractClosedFormSmoothUnivariateDistribution

gov.sandia.cognition.statistics.distribution.GammaDistribution

gov.sandia.cognition.statistics.distribution.GammaDistribution.PDF

All Implemented Interfaces:

Evaluator<java.lang.Double,java.lang.Double>, Vectorizable, ScalarFunction<java.lang.Double>, UnivariateScalarFunction, ClosedFormComputableDistribution<java.lang.Double>, ClosedFormDistribution<java.lang.Double>, ClosedFormUnivariateDistribution<java.lang.Double>, ComputableDistribution<java.lang.Double>, Distribution<java.lang.Double>, DistributionWithMean<java.lang.Double>, EstimableDistribution<java.lang.Double,GammaDistribution>, ProbabilityDensityFunction<java.lang.Double>, ProbabilityFunction<java.lang.Double>, SmoothUnivariateDistribution, UnivariateDistribution<java.lang.Double>, UnivariateProbabilityDensityFunction, CloneableSerializable, java.io.Serializable, java.lang.Cloneable

Enclosing class:

GammaDistribution

public static class GammaDistribution.PDF
extends GammaDistribution
implements UnivariateProbabilityDensityFunction

Closed-form PDF of the Gamma distribution

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class gov.sandia.cognition.statistics.distribution.GammaDistribution

GammaDistribution.CDF, GammaDistribution.MomentMatchingEstimator, GammaDistribution.PDF, GammaDistribution.WeightedMomentMatchingEstimator

Field Summary

Fields inherited from class gov.sandia.cognition.statistics.distribution.GammaDistribution

DEFAULT_SCALE, DEFAULT_SHAPE

Constructor Summary

Constructors

Constructor and Description
PDF() Default constructor.
PDF(double shape, double scale) Creates a new instance of PDF
PDF(GammaDistribution other) Copy constructor

Method Summary

Modifier and Type	Method and Description
double	evaluate(double input) Produces a double output for the given double input
java.lang.Double	evaluate(java.lang.Double input) Evaluates the function on the given input and returns the output.
static double	evaluate(double x, double shape, double scale) Evaluates the Gamma PDF about the input "x", using the given shape and scale
double	evaluateAsDouble(java.lang.Double input) Evaluates the scalar function as a double.
GammaDistribution.PDF	getProbabilityFunction() Gets the distribution function associated with this Distribution, either the PDF or PMF.
double	logEvaluate(double input) Evaluate the natural logarithm of the distribution function.
double	logEvaluate(java.lang.Double input) Evaluate the natural logarithm of the distribution function.
static double	logEvaluate(double input, double shape, double scale) Evaluates the natural logarithm of the PDF.

Methods inherited from class gov.sandia.cognition.statistics.distribution.GammaDistribution

clone, convertFromVector, convertToVector, getCDF, getEstimator, getMaxSupport, getMeanAsDouble, getMinSupport, getRate, getScale, getShape, getVariance, sample, sample, sampleAsDouble, sampleAsDouble, sampleAsDoubles, sampleInto, sampleInto, sampleStandard, setRate, setScale, setShape, toString

Methods inherited from class gov.sandia.cognition.statistics.AbstractClosedFormSmoothUnivariateDistribution

getMean, sampleAsDoubles, sampleInto

Methods inherited from class gov.sandia.cognition.statistics.AbstractDistribution

sample, sample

Methods inherited from class java.lang.Object

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

Methods inherited from interface gov.sandia.cognition.statistics.SmoothUnivariateDistribution

getCDF, getMean, sampleAsDouble, sampleAsDoubles, sampleInto

Methods inherited from interface gov.sandia.cognition.statistics.UnivariateDistribution

getMaxSupport, getMeanAsDouble, getMinSupport, getVariance

Methods inherited from interface gov.sandia.cognition.statistics.Distribution

sample, sample, sampleInto

Methods inherited from interface gov.sandia.cognition.math.matrix.Vectorizable

clone, convertFromVector, convertToVector

Constructor Detail

PDF

public PDF()

Default constructor.

PDF

public PDF(double shape,
           double scale)

Creates a new instance of PDF

Parameters:

shape - Shape parameter of the Gamma distribution, often written as "k", must be greater than zero

scale - Scale parameters of the Gamma distribution, often written as "theta", must be greater than zero. Note that this is the INVERSE of what octave uses!!

PDF

public PDF(GammaDistribution other)

Copy constructor

Parameters:

other - GammaDistribution to copy

Method Detail

evaluate

public java.lang.Double evaluate(java.lang.Double input)

Description copied from interface: Evaluator

Evaluates the function on the given input and returns the output.

Specified by:

evaluate in interface Evaluator<java.lang.Double,java.lang.Double>

Specified by:

evaluate in interface ScalarFunction<java.lang.Double>

Specified by:

evaluate in interface UnivariateScalarFunction

Parameters:

input - The input to evaluate.

Returns:

The output produced by evaluating the input.

evaluateAsDouble

public double evaluateAsDouble(java.lang.Double input)

Description copied from interface: ScalarFunction

Evaluates the scalar function as a double.

Specified by:

evaluateAsDouble in interface ScalarFunction<java.lang.Double>

Specified by:

evaluateAsDouble in interface UnivariateScalarFunction

Parameters:

input - The input value.

Returns:

The scalar output calculated from the given input.

evaluate

public double evaluate(double input)

Description copied from interface: UnivariateScalarFunction

Produces a double output for the given double input

Specified by:

evaluate in interface UnivariateScalarFunction

Parameters:

input - Input to the Evaluator

Returns:

output at the given input

evaluate

public static double evaluate(double x,
                              double shape,
                              double scale)

Evaluates the Gamma PDF about the input "x", using the given shape and scale

Parameters:

x - Input to the PDF

shape - Shape parameter of the Gamma distribution, often written as "k", must be greater than zero

scale - Scale parameters of the Gamma distribution, often written as "theta", must be greater than zero. Note that this is the INVERSE of what octave uses!!

Returns:

p(x;shape,scale)

logEvaluate

public double logEvaluate(java.lang.Double input)

Description copied from interface: ProbabilityFunction

Evaluate the natural logarithm of the distribution function. This is sometimes more efficient than evaluating the distribution function itself, and when evaluating the product of many independent or exchangeable samples.

Specified by:

logEvaluate in interface ProbabilityFunction<java.lang.Double>

Parameters:

input - The input to be evaluated

Returns:

Natural logarithm of the distribution function.

logEvaluate

public double logEvaluate(double input)

Description copied from interface: UnivariateProbabilityDensityFunction

Evaluate the natural logarithm of the distribution function. This is sometimes more efficient than evaluating the distribution function itself, and when evaluating the product of many independent or exchangeable samples.

Specified by:

logEvaluate in interface UnivariateProbabilityDensityFunction

Parameters:

input - The input value.

Returns:

The natural logarithm of the distribution function.

logEvaluate

public static double logEvaluate(double input,
                                 double shape,
                                 double scale)

Evaluates the natural logarithm of the PDF.

Parameters:

input - Input to consider.

shape - Shape factor.

scale - Scale factor.

Returns:

Natural logarithm of the PDF.

getProbabilityFunction

public GammaDistribution.PDF getProbabilityFunction()

Description copied from interface: ComputableDistribution

Gets the distribution function associated with this Distribution, either the PDF or PMF.

Specified by:

getProbabilityFunction in interface ComputableDistribution<java.lang.Double>

Specified by:

getProbabilityFunction in interface ProbabilityDensityFunction<java.lang.Double>

Specified by:

getProbabilityFunction in interface SmoothUnivariateDistribution

Specified by:

getProbabilityFunction in interface UnivariateProbabilityDensityFunction

Overrides:

getProbabilityFunction in class GammaDistribution

Returns:

Distribution function associated with this Distribution.