ConstrEx.java

//  ConstrEx.java
//
//  Author:
//       Antonio J. Nebro <antonio@lcc.uma.es>
//       Juan J. Durillo <durillo@lcc.uma.es>
//
//  Copyright (c) 2011 Antonio J. Nebro, Juan J. Durillo
//
//  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 ConstrEx
 */
@SuppressWarnings("serial")
public class ConstrEx extends AbstractDoubleProblem implements ConstrainedProblem<DoubleSolution> {

  public OverallConstraintViolation<DoubleSolution> overallConstraintViolationDegree ;
  public NumberOfViolatedConstraints<DoubleSolution> numberOfViolatedConstraints ;

  /**
   * Constructor
   * Creates a default instance of the ConstrEx problem
   */
  public ConstrEx() {
    setNumberOfVariables(2);
    setNumberOfObjectives(2);
    setNumberOfConstraints(2);
    setName("ConstrEx");

    List<Double> lowerLimit = Arrays.asList(0.1, 0.0) ;
    List<Double> upperLimit = Arrays.asList(1.0, 5.0) ;

    setLowerLimit(lowerLimit);
    setUpperLimit(upperLimit);

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

  /** Evaluate() method */
  @Override
  public void evaluate(DoubleSolution solution) {
    double [] f = new double[getNumberOfObjectives()];
    f[0] = solution.getVariableValue(0) ;
    f[1] = (1.0 + solution.getVariableValue(1))/solution.getVariableValue(0);
    
    solution.setObjective(0,f[0]);
    solution.setObjective(1,f[1]);
  }

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

    double x1 = solution.getVariableValue(0) ;
    double x2 = solution.getVariableValue(1) ;
        
    constraint[0] =  (x2 + 9*x1 -6.0) ;
    constraint[1] =  (-x2 + 9*x1 -1.0);
        
    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);
  }
}