Class DEStatistics

  extended by ec.Statistics
      extended by
All Implemented Interfaces:
Setup, Singleton,

public class DEStatistics
extends Statistics

DEStatistics provides a straightforward solution to one problem many existing ECJ statistics classes have when used in conjunction with Differential Evolution (DE), namely reporting the fitness of individuals after they have been evaluated. The problem stems from the fact that all individuals create children (there is no selection pressure). Rather, the child competes immediately with its parent, and only the best of the two survives. As a result, all other statistics classes would report the fitness of the child, as opposed to the fitness of the better of the child and the parent. In many cases, that fitness might provide misleading information (for example, it might appear that the average fitness of the population is too random, and that there is no evident progress). To fix this, the DEStatistics class performs the competition between the child and the parent right before other statistics classes might be invoked. Make sure DEStatistics is set as the main statistics class, and the other are set as its children.

Liviu Panait
See Also:
Serialized Form

Field Summary
Fields inherited from class ec.Statistics
Constructor Summary
Method Summary
 void postEvaluationStatistics(EvolutionState state)
          GENERATIONAL: Called immediately after evaluation occurs.
Methods inherited from class ec.Statistics
finalStatistics, generationBoundaryStatistics, individualsBredStatistics, individualsEvaluatedStatistics, postBreedingStatistics, postCheckpointStatistics, postInitialEvaluationStatistics, postInitializationStatistics, postPostBreedingExchangeStatistics, postPreBreedingExchangeStatistics, preBreedingStatistics, preCheckpointStatistics, preEvaluationStatistics, preInitialEvaluationStatistics, preInitializationStatistics, prePostBreedingExchangeStatistics, prePreBreedingExchangeStatistics, setup
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail


public DEStatistics()
Method Detail


public void postEvaluationStatistics(EvolutionState state)
Description copied from class: Statistics
GENERATIONAL: Called immediately after evaluation occurs.

postEvaluationStatistics in class Statistics