org.um.feri.ears.problems.unconstrained.ProblemAckley.java Source code

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Here is the source code for org.um.feri.ears.problems.unconstrained.ProblemAckley.java

Source

package org.um.feri.ears.problems.unconstrained;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

import org.apache.commons.lang3.ArrayUtils;
import org.um.feri.ears.problems.Problem;

/**
 * Problem function!
 * <p>
 * 
 * @author Matej Crepinsek
 * @version 1
 * 
 *          <h3>License</h3>
 * 
 *          Copyright (c) 2011 by Matej Crepinsek. <br>
 *          All rights reserved. <br>
 * 
 *          <p>
 *          Redistribution and use in source and binary forms, with or without
 *          modification, are permitted provided that the following conditions
 *          are met:
 *          <ul>
 *          <li>Redistributions of source code must retain the above copyright
 *          notice, this list of conditions and the following disclaimer.
 *          <li>Redistributions in binary form must reproduce the above
 *          copyright notice, this list of conditions and the following
 *          disclaimer in the documentation and/or other materials provided with
 *          the distribution.
 *          <li>Neither the name of the copyright owners, their employers, nor
 *          the names of its contributors may be used to endorse or promote
 *          products derived from this software without specific prior written
 *          permission.
 *          </ul>
 *          <p>
 *          THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *          "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *          LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 *          FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 *          COPYRIGHT OWNERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 *          INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 *          BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 *          LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 *          CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 *          LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 *          ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 *          POSSIBILITY OF SUCH DAMAGE.
 * 
 */
public class ProblemAckley extends Problem {
    // Ackley
    // http://www-optima.amp.i.kyoto-u.ac.jp/member/student/hedar/Hedar_files/TestGO_files/Page295.htm
    public ProblemAckley(int d) {
        super(d, 0);

        lowerLimit = new ArrayList<Double>(Collections.nCopies(numberOfDimensions, -32.0));
        upperLimit = new ArrayList<Double>(Collections.nCopies(numberOfDimensions, 32.0));

        name = "Ackley";
    }

    public double eval(double x[]) {
        double v = 0;
        double a = 20;
        double b = 0.2;
        double c = 2 * Math.PI;
        double s1 = 0;
        double s2 = 0;
        for (int i = 0; i < numberOfDimensions; i++) {
            s1 = s1 + x[i] * x[i];
            s2 = s2 + Math.cos(c * x[i]);
        }
        v = -a * Math.exp(-b * Math.sqrt(1. / numberOfDimensions * s1)) - Math.exp(1. / numberOfDimensions * s2) + a
                + Math.exp(1.);
        return v;
    }

    @Override
    public double eval(Double[] ds) {
        return eval(ArrayUtils.toPrimitive(ds));
    }

    public double getOptimumEval() {
        return 0;
    }

    @Override
    public boolean isFirstBetter(Double[] x, double eval_x, Double[] y, double eval_y) {
        return eval_x < eval_y;
    }
}