/*
* RapidMiner
*
* Copyright (C) 2001-2008 by Rapid-I and the contributors
*
* Complete list of developers available at our web site:
*
* http://rapid-i.com
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see http://www.gnu.org/licenses/.
*/
package com.rapidminer.tools.math.optimization.ec.es;
import java.util.LinkedList;
import java.util.List;
import java.util.Random;
/**
* Selects a given fixed number of individuals by uniformly sampling from the
* current population until the desired population size is reached.
*
* @author Ingo Mierswa
* @version $Id: UniformSelection.java,v 1.3 2008/05/09 19:23:17 ingomierswa Exp $
*/
public class UniformSelection implements PopulationOperator {
private int popSize;
private boolean keepBest;
private Random random;
public UniformSelection(int popSize, boolean keepBest, Random random) {
this.popSize = popSize;
this.keepBest = keepBest;
this.random = random;
}
/** The default implementation returns true for every generation. */
public boolean performOperation(int generation) {
return true;
}
public void operate(Population population) {
List<Individual> newGeneration = new LinkedList<Individual>();
if (keepBest) {
newGeneration.add(population.getBestEver());
}
while (newGeneration.size() < popSize) {
newGeneration.add(population.get(random.nextInt(population.getNumberOfIndividuals())));
}
population.clear();
population.addAll(newGeneration);
}
}