selectdifference.java

遗传算法源代码,实现了选择操作、交叉操作和变异操作

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/**
 * SelectDifference Class
 *
 * location: net.openai.ai.ga.selection.common.SelectDifference
 *
 */
package net.openai.ai.ga.selection.common;

import net.openai.ai.ga.selection.*;
import net.openai.ai.ga.population.*;
import net.openai.ai.ga.cell.*;

import java.util.Collection;

/**
 * <code>SelectDifference</code> is a <code>SelectionAlgorithm</code>
 * that will return the difference of the results of two specified <code>
 * SelectionAlgorithm</code>s.
 *
 * @author	Jared Grubb
 * @version	%I%, %G%
 * @since	JDK1.3
 */
public class SelectDifference implements SelectionAlgorithm {
    private SelectionAlgorithm arg1, arg2;

    /**
     * Creates a new <code>SelectDifference</code> object for taking the
     * difference of the <code>Population</code>s returned by the two
     * passed <code>SelectionAlgorithm</code>s.
     *
     * @param first the first <code>SelectionAlgorithm</code>
     * @param second the second <code>SelectionAlgorithm</code>
     */
    public SelectDifference(SelectionAlgorithm first,
                       SelectionAlgorithm second) {
        this.arg1 = first;
        this.arg2 = second;
    }

    /**
     * Returns a <code>Population</code> that represents the difference
     * (disjunction) of the two <code>SelectionAlgorithm</code>s specified in
     * the constructor. The return is the result of the first selection
     * algorithm with the results of the second removed from it via
     * <code>Population.removeCells</code> method.
     *
     * If the first selection algorithm returns a <code>null</code> then a
     * <code>NullPointerException</code> will be thrown. If the second one
     * returns a <code>null</code>, the the results of the first will be
     * returned unchanged.
     *
     * @param pop  the <code>Population</code> to choose from
     * @return the difference <code>Population</code> of the two selection
     *         algorithms
     */
    public Population selectFromPopulation(Population pop) {
        Population toReturn = arg1.selectFromPopulation(pop);
        toReturn.removeCells(arg2.selectFromPopulation(pop));
        return toReturn;
    }
}



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