org.ai_heuristic.algo.prob

Class Entropy

java.lang.Object

org.ai_heuristic.functs.Function

org.ai_heuristic.algo.prob.Entropy

All Implemented Interfaces:

FunctionDef

public class Entropy
extends Function

This class implements a discrete Entropy evaluation. This is the randomness or purity of the distribution, comparing between each data point in the dataset. The result is factored to be in the range 0 to 1, where 1 is maximum purity. If entropy measures the amount of disorder, then typically, a larger values means less pure and more disorder, but to mathCompare with the other metrics this has been reversed by dividing 1.0 by the entropy value. You can reverse this again in your code by dividing 1.0 by the result again when it is returned. Each data point is numerical and should be of type Float, Double, Long or Integer.

Some help from Ethan Croteau at http://www.Planet-Source-Code.com/vb/scripts/ShowCode.asp?txtCodeId=3319&lngWId=2

Author:

Kieran Greer

Field Summary

Fields inherited from class org.ai_heuristic.functs.Function

config, mathCompare, valueType

Constructor Summary

Constructors

Constructor and Description
Entropy() Create a new instance of Entropy.
Entropy(java.lang.String thisValueType) Create a new instance of Entropy.

Method Summary

Modifier and Type	Method and Description
ReplySet	evaluate(MetricDataset dataset) Evaluate the comparison of a list of values for the same element and return the result.
protected void	initialise() Initialise the function values, setting the config parameters or other.
Function	newInstance() Create and return a new instance of the function, initialised with this function's value type valueType and mathOperation evaluator mathCompare.

Methods inherited from class org.ai_heuristic.functs.Function

checkValueType, createFunction, createFunction, createFunction, getConfigParams, innerObject, isLegalNumber, setConfigParams, setEvaluator, setValueType

Methods inherited from class java.lang.Object

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

Constructor Detail

Entropy

public Entropy()
        throws java.lang.Exception

Create a new instance of Entropy.

Throws:

java.lang.Exception - any error.

Entropy

public Entropy(java.lang.String thisValueType)
        throws java.lang.Exception

Create a new instance of Entropy.

Parameters:

thisValueType - the type of object being evaluated.

Throws:

java.lang.Exception - any error.

Method Detail

initialise

protected void initialise()
                   throws java.lang.Exception

Initialise the function values, setting the config parameters or other.

Specified by:

initialise in class Function

Throws:

java.lang.Exception - any error.

evaluate

public ReplySet evaluate(MetricDataset dataset)
                  throws java.lang.Exception

Evaluate the comparison of a list of values for the same element and return the result.

Specified by:

evaluate in interface FunctionDef

Overrides:

evaluate in class Function

Parameters:

dataset - value dataset. This should store the list of separate data points. Each point represents a different value for the same entity, where the MetricValue name can be null and the value is its number of occurrences (integer).

Returns:

the result of applying the operator to the values.

Throws:

java.lang.Exception - any error.

newInstance

public Function newInstance()
                     throws java.lang.Exception

Create and return a new instance of the function, initialised with this function's value type valueType and mathOperation evaluator mathCompare.

Returns:

a new instance of this function.

Throws:

java.lang.Exception - any error.