/* Copyright 2009-2016 David Hadka
*
* This file is part of the MOEA Framework.
*
* The MOEA Framework is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or (at your
* option) any later version.
*
* The MOEA Framework 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with the MOEA Framework. If not, see <http://www.gnu.org/licenses/>.
*/
package org.moeaframework.problem.BBOB2016;
import org.moeaframework.core.Solution;
import org.moeaframework.core.variable.EncodingUtils;
/*
* The following source code is derived from the Coco Framework available at
* <https://github.com/numbbo/coco> under the 3-clause BSD license. The
* original code is copyright 2013 by the NumBBO/CoCO team. See the AUTHORS
* file located in the Coco Framework repository for more details.
*/
/**
* The 101-peak Gallagher function. It is not intended for this function to be
* used directly since the BBOB test suite applies additional transformations
* to the test functions.
* <p>
* Properties:
* <ul>
* <li>Multimodal (with random locations of local optima)
* </ul>
*/
public class Gallagher extends BBOBFunction {
/**
* The rotation matrix.
*/
private final double[][] rotation;
/**
* The location of the local optima.
*/
private final double[][] xLocal;
/**
* Controls the steepness of the peaks.
*/
private final double[][] arrScales;
/**
* The magnitude of the peaks.
*/
private final double[] peaks;
/**
* Constructs a new instance of the 101-peak Gallagher function.
*
* @param numberOfVariables the number of decision variables
* @param rotation the rotation matrix
* @param xLocal the location of the local optima
* @param arrScales controls the steepness of the peaks
* @param peaks the magnitude of the peaks
*/
public Gallagher(int numberOfVariables, double[][] rotation, double[][] xLocal, double[][] arrScales, double[] peaks) {
super(numberOfVariables);
this.rotation = rotation;
this.xLocal = xLocal;
this.arrScales = arrScales;
this.peaks = peaks;
}
@Override
public void evaluate(Solution solution) {
double[] x = EncodingUtils.getReal(solution);
double[] tmx = new double[x.length];
double f = 0.0;
double a = 0.1;
double penalty = 0.0;
double ftrue = 0.0;
double fac = -0.5 / x.length;
/* Boundary handling */
for (int i = 0; i < x.length; i++) {
double tmp = Math.abs(x[i]) - 5.0;
if (tmp > 0.0) {
penalty += tmp*tmp;
}
}
/* Transformation in search space */
for (int i = 0; i < x.length; i++) {
tmx[i] = 0.0;
for (int j = 0; j < x.length; j++) {
tmx[i] += rotation[i][j] * x[j];
}
}
/* Computation core */
for (int i = 0; i < peaks.length; i++) {
double tmp2 = 0.0;
for (int j = 0; j < x.length; j++) {
double tmp1 = (tmx[j] - xLocal[j][i]);
tmp2 += arrScales[i][j] * tmp1 * tmp1;
}
tmp2 = peaks[i] * Math.exp(fac * tmp2);
f = Math.max(f, tmp2);
}
f = 10.0 - f;
if (f > 0.0) {
ftrue = Math.log(f) / a;
ftrue = Math.pow(Math.exp(ftrue + 0.49 * (Math.sin(ftrue) + Math.sin(0.79 * ftrue))), a);
} else if (f < 0.0) {
ftrue = Math.log(-f) / a;
ftrue = -Math.pow(Math.exp(ftrue + 0.49 * (Math.sin(0.55 * ftrue) + Math.sin(0.31 * ftrue))), a);
} else {
ftrue = f;
}
solution.setObjective(0, ftrue*ftrue + penalty);
}
}