edu.udo.cs.yale.operator.features.weighting
Class FeatureWeighting

java.lang.Object
  edu.udo.cs.yale.operator.Operator
      edu.udo.cs.yale.operator.OperatorChain
          edu.udo.cs.yale.operator.features.FeatureOperator
              edu.udo.cs.yale.operator.features.weighting.FeatureWeighting

All Implemented Interfaces:

ConfigurationListener

Direct Known Subclasses:

BackwardWeighting, ForwardWeighting

public abstract class FeatureWeighting
extends FeatureOperator

This operator performs the weighting under the naive assumption that the features are independent from each other. Each attribute is weighted with a linear search. This approach may deliver good results after short time if the features indeed are not highly correlated.
The ideas of forward selection and backward elimination can easily be used for the weighting with help of a SimpleWeighting.

Version:

$Id: FeatureWeighting.java,v 1.14 2006/03/27 13:22:00 ingomierswa Exp $

Author:

Ingo Mierswa

Field Summary

private int	generationsWOImp
private java.util.List<PopulationOperator>	postOps
private java.util.List<PopulationOperator>	preOps

Constructor Summary

FeatureWeighting(OperatorDescription description)

Method Summary

IOObject[]	apply() Applies the feature operator: collects the pre- and postevaluation operators create an initial population evaluate the initial population loop as long as solution is not good enough apply all pre evaluation operators evaluate the population update the population's best individual apply all post evaluation operators return all generation's best individual
java.util.List<ParameterType>	getParameterTypes() Returns a list of ParameterTypes describing the parameters of this operator.
java.util.List<PopulationOperator>	getPostEvaluationPopulationOperators(ExampleSet eSet) Must return a list of PopulationOperators.
java.util.List<PopulationOperator>	getPreEvaluationPopulationOperators(ExampleSet eSet) Must return a list of PopulationOperators.
abstract PopulationOperator	getWeightingOperator(java.lang.String parameter)
boolean	solutionGoodEnough(Population population) Has to return true if the main loop can be stopped because a solution is concidered to be good enough according to some criterion.

Methods inherited from class edu.udo.cs.yale.operator.features.FeatureOperator

createInitialPopulation, evaluate, evaluate, getCheckForMaximum, getInnerOperatorCondition, getInputClasses, getMaxNumberOfInnerOperators, getMinNumberOfInnerOperators, getNumberOfSteps, getOutputClasses, getRandom, setCheckForMaximum

Methods inherited from class edu.udo.cs.yale.operator.OperatorChain

addAddListener, addOperator, addOperator, checkDeprecations, checkIO, checkNumberOfInnerOperators, checkProperties, clearErrorList, clearStepCounter, cloneOperator, countStep, createExperimentTree, delete, experimentFinished, experimentStarts, getAllInnerOperators, getCurrentStep, getIndexOfOperator, getInnerOperatorForName, getInnerOperatorsXML, getNumberOfAllOperators, getNumberOfChildrensSteps, getNumberOfOperators, getOperator, getOperatorFromAll, getOperators, isEnabled, performAdditionalChecks, removeAddListener, removeOperator, setEnabled, setExperiment, shouldReturnInnerOutput

Methods inherited from class edu.udo.cs.yale.operator.Operator

addError, addValue, addWarning, apply, createExperimentTree, createFromXML, createMarkedExperimentTree, getAddOnlyAdditionalOutput, getApplyCount, getDeliveredOutputClasses, getDeprecationInfo, getDesiredInputClasses, getErrorList, getExperiment, getInput, getInput, getInput, getInputDescription, getIOContainerForInApplyLoopBreakpoint, getName, getOperatorClassName, getOperatorDescription, getParameter, getParameterAsBoolean, getParameterAsColor, getParameterAsDouble, getParameterAsFile, getParameterAsInt, getParameterAsString, getParameterList, getParameters, getParameterType, getParent, getStartTime, getStatus, getUserDescription, getValue, getValues, getXML, hasBreakpoint, hasBreakpoint, hasInput, inApplyLoop, isParameterSet, logMessage, register, remove, rename, resume, setBreakpoint, setInput, setListParameter, setOperatorParameters, setParameter, setParameters, setParent, setUserDescription, toString, writeXML

Methods inherited from class java.lang.Object

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

Field Detail

preOps

private java.util.List<PopulationOperator> preOps

postOps

private java.util.List<PopulationOperator> postOps

generationsWOImp

private int generationsWOImp

Constructor Detail

FeatureWeighting

public FeatureWeighting(OperatorDescription description)

Method Detail

getWeightingOperator

public abstract PopulationOperator getWeightingOperator(java.lang.String parameter)

apply

public IOObject[] apply()
                 throws OperatorException

Description copied from class: FeatureOperator

Applies the feature operator:

1. collects the pre- and postevaluation operators
2. create an initial population
3. evaluate the initial population
4. loop as long as solution is not good enough
   1. apply all pre evaluation operators
   2. evaluate the population
   3. update the population's best individual
   4. apply all post evaluation operators
5. return all generation's best individual

Overrides:

apply in class FeatureOperator

Returns:

the last inner operator's output or the input itself if the chain is empty.

Throws:

OperatorException

solutionGoodEnough

public boolean solutionGoodEnough(Population population)

Description copied from class: FeatureOperator

Has to return true if the main loop can be stopped because a solution is concidered to be good enough according to some criterion.

Specified by:

solutionGoodEnough in class FeatureOperator

getPreEvaluationPopulationOperators

public java.util.List<PopulationOperator> getPreEvaluationPopulationOperators(ExampleSet eSet)

Description copied from class: FeatureOperator

Must return a list of PopulationOperators. All operators are applied to the population in their order within the list before the population is evaluated. Since this methode is invoked only once the list cannot by dynamically changed during runtime.

Specified by:

getPreEvaluationPopulationOperators in class FeatureOperator

getPostEvaluationPopulationOperators

public java.util.List<PopulationOperator> getPostEvaluationPopulationOperators(ExampleSet eSet)

Description copied from class: FeatureOperator

Must return a list of PopulationOperators. All operators are applied to the population in their order within the list after the population is evaluated. Since this methode is invoked only once the list cannot by dynamically changed during runtime.

Specified by:

getPostEvaluationPopulationOperators in class FeatureOperator

getParameterTypes

public java.util.List<ParameterType> getParameterTypes()

Description copied from class: Operator

Returns a list of ParameterTypes describing the parameters of this operator. The default implementation returns an empty list if no input objects can be retained and special parameters for those input objects which can be prevented from being consumed.

Overrides:

getParameterTypes in class FeatureOperator