edu.udo.cs.yale.operator.features
Class Population

java.lang.Object
  edu.udo.cs.yale.operator.features.Population

public class Population
extends java.lang.Object

A set of individuals. Stores generation number and best individuals.

Version:

$Id: Population.java,v 2.24 2006/08/03 14:39:31 ingomierswa Exp $

Author:

Simon Fischer, Ingo Mierswa

Field Summary

private Individual	bestEver All generations' best individual.
private PerformanceVector	bestPerformanceEver All generations' best performance.
private Individual	currentBest The currently best individual.
private PerformanceVector	currentBestPerformance The currently best performance.
private int	generation Current generation number
private int	generationOfLastImproval Generation of the last improval.
private java.util.ArrayList<Individual>	individuals List of ExampleSet
static java.util.Comparator<Individual>	PERFORMANCE_COMPARATOR

Constructor Summary

Population()
Construct an empty generation.

Method Summary

void	add(Individual individual) Adds a single individual.
void	addAllIndividuals(java.util.Collection<Individual> newIndividuals) Adds all individuals from the given collection.
void	clear() Removes all individuals.
boolean	empty() Returns true is the population contains no individuals.
Individual	get(int i) Returns a single individual.
Individual	getBestIndividualEver() Returns all generations' best individual.
PerformanceVector	getBestPerformanceEver() Returns the best performance.
Individual	getCurrentBest() Returns the last generation's best individual.
PerformanceVector	getCurrentBestPerformance() Returns the last generation's best performance.
int	getGeneration() Returns the current number of the generation.
int	getGenerationsWithoutImproval() Returns the number of generations without improval.
int	getNumberOfIndividuals() Returns the number of all individuals.
void	nextGeneration() Increase the generation number by one.
void	remove(Individual individual) Removes a single individual.
void	remove(int i) Removes a single individual.
private Individual	searchBest() Finds the current generation's best individual.
void	sort() Sorts the individuals in ascending order according to their performance, thus the best one will be in last position.
java.lang.String	toString()
void	updateEvaluation() Remember the current generation's best individual and update the best individual.

Methods inherited from class java.lang.Object

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

Field Detail

PERFORMANCE_COMPARATOR

public static final java.util.Comparator<Individual> PERFORMANCE_COMPARATOR

individuals

private java.util.ArrayList<Individual> individuals

List of ExampleSet

generation

private int generation

Current generation number

generationOfLastImproval

private int generationOfLastImproval

Generation of the last improval.

bestEver

private Individual bestEver

All generations' best individual.

bestPerformanceEver

private PerformanceVector bestPerformanceEver

All generations' best performance.

currentBest

private Individual currentBest

The currently best individual.

currentBestPerformance

private PerformanceVector currentBestPerformance

The currently best performance.

Constructor Detail

Population

public Population()

Construct an empty generation.

Method Detail

clear

public void clear()

Removes all individuals.

add

public void add(Individual individual)

Adds a single individual.

addAllIndividuals

public void addAllIndividuals(java.util.Collection<Individual> newIndividuals)

Adds all individuals from the given collection.

remove

public void remove(Individual individual)

Removes a single individual.

remove

public void remove(int i)

Removes a single individual.

get

public Individual get(int i)

Returns a single individual.

getNumberOfIndividuals

public int getNumberOfIndividuals()

Returns the number of all individuals.

empty

public boolean empty()

Returns true is the population contains no individuals.

nextGeneration

public void nextGeneration()

Increase the generation number by one.

getGeneration

public int getGeneration()

Returns the current number of the generation.

getGenerationsWithoutImproval

public int getGenerationsWithoutImproval()

Returns the number of generations without improval.

updateEvaluation

public void updateEvaluation()

Remember the current generation's best individual and update the best individual.

searchBest

private Individual searchBest()

Finds the current generation's best individual. Returns null, if there are unevaluated individuals. Probably you will want to use bestEver() or lastBest() because they don't cause comparisons.

getBestPerformanceEver

public PerformanceVector getBestPerformanceEver()

Returns the best performance.

getBestIndividualEver

public Individual getBestIndividualEver()

Returns all generations' best individual.

getCurrentBest

public Individual getCurrentBest()

Returns the last generation's best individual.

getCurrentBestPerformance

public PerformanceVector getCurrentBestPerformance()

Returns the last generation's best performance.

sort

public void sort()

Sorts the individuals in ascending order according to their performance, thus the best one will be in last position.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object