Binh2.java

//  Binh2.java
//
//  Author:
//       Antonio J. Nebro <antonio@lcc.uma.es>
//
//  Copyright (c) 2012 Antonio J. Nebro
//
//  This program 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.
//
//  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 Lesser General Public License for more details.
// 
//  You should have received a copy of the GNU Lesser General Public License
//  along with this program.  If not, see <http://www.gnu.org/licenses/>.

package org.uma.jmetal.problem.multiobjective;

import org.uma.jmetal.problem.ConstrainedProblem;
import org.uma.jmetal.problem.impl.AbstractDoubleProblem;
import org.uma.jmetal.solution.DoubleSolution;
import org.uma.jmetal.util.solutionattribute.impl.NumberOfViolatedConstraints;
import org.uma.jmetal.util.solutionattribute.impl.OverallConstraintViolation;

import java.util.Arrays;
import java.util.List;

/** Class representing problem Binh2 */
@SuppressWarnings("serial")
public class Binh2 extends AbstractDoubleProblem implements ConstrainedProblem<DoubleSolution> {

  public OverallConstraintViolation<DoubleSolution> overallConstraintViolationDegree ;
  public NumberOfViolatedConstraints<DoubleSolution> numberOfViolatedConstraints ;
  /**
   * Constructor
   * Creates a default instance of the Binh2 problem
   */
  public Binh2() {
    setNumberOfVariables(2);
    setNumberOfObjectives(2);
    setNumberOfConstraints(2);
    setName("Binh2");

    List<Double> lowerLimit = Arrays.asList(0.0, 0.0) ;
    List<Double> upperLimit = Arrays.asList(5.0, 3.0) ;

    setLowerLimit(lowerLimit);
    setUpperLimit(upperLimit);

    overallConstraintViolationDegree = new OverallConstraintViolation<DoubleSolution>() ;
    numberOfViolatedConstraints = new NumberOfViolatedConstraints<DoubleSolution>() ;
  }

  /** Evaluate() method */
  @Override
  public void evaluate(DoubleSolution solution) {
    double[] fx = new double[getNumberOfObjectives()];
    double[] x = new double[getNumberOfVariables()];
    for (int i = 0; i < getNumberOfVariables(); i++) {
      x[i] = solution.getVariableValue(i) ;
    }

    fx[0] = 4.0 * x[0] * x[0] + 4 * x[1] * x[1];
    fx[1] = (x[0] - 5.0) * (x[0] - 5.0) + (x[1] - 5.0) * (x[1] - 5.0);

    solution.setObjective(0, fx[0]);
    solution.setObjective(1, fx[1]);
  }

  /** EvaluateConstraints() method */
  @Override
  public void evaluateConstraints(DoubleSolution solution)  {
    double[] constraint = new double[this.getNumberOfConstraints()];

    double x0 = solution.getVariableValue(0) ;
    double x1 = solution.getVariableValue(1) ;

    constraint[0] = -1.0 * (x0 - 5) * (x0 - 5) - x1 * x1 + 25.0;
    constraint[1] = (x0 - 8) * (x0 - 8) + (x1 + 3) * (x1 + 3) - 7.7;

    double overallConstraintViolation = 0.0;
    int violatedConstraints = 0;
    for (int i = 0; i < this.getNumberOfConstraints(); i++) {
      if (constraint[i] < 0.0) {
        overallConstraintViolation += constraint[i];
        violatedConstraints++;
      }
    }

    overallConstraintViolationDegree.setAttribute(solution, overallConstraintViolation);
    numberOfViolatedConstraints.setAttribute(solution, violatedConstraints);
  }
}