## gov.sandia.cognition.statistics Interface ProbabilityMassFunction<DataType>

Type Parameters:
`DataType` - Value for the domain (x-axis, independent variable), may be something like an Integer, etc.
All Superinterfaces:
Cloneable, CloneableSerializable, ComputableDistribution<DataType>, DiscreteDistribution<DataType>, Distribution<DataType>, Evaluator<DataType,Double>, ProbabilityFunction<DataType>, Serializable
All Known Subinterfaces:
All Known Implementing Classes:

```@PublicationReference(author="Wikipedia",
title="Probability mass function",
type=WebPage,
year=2009,
url="http://en.wikipedia.org/wiki/Probability_mass_function")
public interface ProbabilityMassFunction<DataType>extends ProbabilityFunction<DataType>, DiscreteDistribution<DataType>```

The `ProbabilityMassFunction` interface defines the functionality of a probability mass function. A PMF has the following properties: - The domain is a countably finite set - The dependent values sum to 1.0 - PMF(x) == "probability that a random variable takes value x" - PMF(x) >= 0.0 for all x - By consequence, PMF(x) <= 1.0 for all x

Since:
2.0
Author:
Justin Basilico

Method Summary
` double` `getEntropy()`
Gets the entropy of the values in the histogram.
` ProbabilityMassFunction<DataType>` `getProbabilityFunction()`
Gets the distribution function associated with this Distribution, either the PDF or PMF.

Methods inherited from interface gov.sandia.cognition.statistics.ProbabilityFunction
`logEvaluate`

Methods inherited from interface gov.sandia.cognition.evaluator.Evaluator
`evaluate`

Methods inherited from interface gov.sandia.cognition.statistics.DiscreteDistribution
`getDomain, getDomainSize`

Methods inherited from interface gov.sandia.cognition.statistics.Distribution
`sample, sample`

Methods inherited from interface gov.sandia.cognition.util.CloneableSerializable
`clone`

Method Detail

### getProbabilityFunction

`ProbabilityMassFunction<DataType> 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<DataType>`
Specified by:
`getProbabilityFunction` in interface `DiscreteDistribution<DataType>`
Returns:
Distribution function associated with this Distribution.

### getEntropy

`double getEntropy()`
Gets the entropy of the values in the histogram.

Returns:
The entropy of the values in the histogram.