/* 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.misc;
import org.moeaframework.core.Solution;
import org.moeaframework.core.variable.RealVariable;
import org.moeaframework.problem.AbstractProblem;
/**
* The Poloni problem. Van Veldhuizen observed a typo in the original paper;
* this implementation uses Van Veldhuizen's version of the problem.
* <p>
* Properties:
* <ul>
* <li>Disconnected Pareto set
* <li>Disconnected and convex Pareto front
* <li>Maximization (objectives are negated)
* </ul>
* <p>
* References:
* <ol>
* <li>Van Veldhuizen, D. A (1999). "Multiobjective Evolutionary Algorithms:
* Classifications, Analyses, and New Innovations." Air Force Institute
* of Technology, Ph.D. Thesis, Appendix B.
* <li>Poloni, C., et al. (1996). "Multiobjective Optimization by GAs:
* Application to System and Component Design." Computational Methods in
* Applied Sciences '96: Invited Lectures and Special Technological
* Sessions of the Third ECCOMAS Computational Fluid Dynamics Conference
* and the Second ECCOMAS Conference on Numerical Methods in Engineering,
* pp. 258-264.
* </ol>
*/
public class Poloni extends AbstractProblem {
/**
* Constructs the Poloni problem.
*/
public Poloni() {
super(2, 2);
}
@Override
public void evaluate(Solution solution) {
double x = ((RealVariable)solution.getVariable(0)).getValue();
double y = ((RealVariable)solution.getVariable(1)).getValue();
double A1 = 0.5*Math.sin(1.0) - 2.0*Math.cos(1.0) + Math.sin(2.0) -
1.5*Math.cos(2.0);
double A2 = 1.5*Math.sin(1.0) - Math.cos(1.0) + 2.0*Math.sin(2.0) -
0.5*Math.cos(2.0);
double B1 = 0.5*Math.sin(x) - 2.0*Math.cos(x) + Math.sin(y) -
1.5*Math.cos(y);
double B2 = 1.5*Math.sin(x) - Math.cos(x) + 2.0*Math.sin(y) -
0.5*Math.cos(y);
double f1 = 1 + Math.pow(A1 - B1, 2.0) + Math.pow(A2 - B2, 2.0);
double f2 = Math.pow(x + 3.0, 2.0) + Math.pow(y + 1.0, 2.0);
solution.setObjective(0, f1);
solution.setObjective(1, f2);
}
@Override
public Solution newSolution() {
Solution solution = new Solution(2, 2);
solution.setVariable(0, new RealVariable(-Math.PI, Math.PI));
solution.setVariable(1, new RealVariable(-Math.PI, Math.PI));
return solution;
}
}