dtlz7.java

关于多目标优化的代码

/**
 * DTLZ7.java
 *
 * @author Antonio J. Nebro
 * @author Juanjo Durillo
 * @version 1.0
 * Created on 16 de octubre de 2006, 17:30
 */
package jmetal.problems.DTLZ;

import jmetal.base.*;
import jmetal.base.Configuration.*;
import jmetal.util.JMException;

/**
 * Class representing problem DTLZ7
 */
public class DTLZ7 extends Problem{
   
 /**
  * Creates a default DTLZ7 problem instance (22 variables and 3 objectives)
  * @param solutionType The solution type must "Real" or "BinaryReal". 
  */
  public DTLZ7(String solutionType){
    this(22,3,solutionType);
  } // DTLZ7
    
 /**
  * Creates a new DTLZ7 problem instance
  * @param numberOfVariables Number of variables
  * @param numberOfObjectives Number of objective functions
  * @param solutionType The solution type must "Real" or "BinaryReal". 
  */
  public DTLZ7(Integer numberOfVariables,
  		         Integer numberOfObjectives, 
  		         String  solutionType) {
    numberOfVariables_  = numberOfVariables.intValue();
    numberOfObjectives_ = numberOfObjectives.intValue();
    numberOfConstraints_= 0;
    problemName_        = "DTLZ7";
        
    lowerLimit_ = new double[numberOfVariables_];
    upperLimit_ = new double[numberOfVariables_];
    for (int var = 0; var < numberOfVariables_; var++){
      lowerLimit_[var] = 0.0;
      upperLimit_[var] = 1.0;
    }
        
    solutionType_ = Enum.valueOf(SolutionType_.class, solutionType) ; 
    
    // All the variables are of the same type, so the solutionType name is the
    // same than the variableType name
    variableType_ = new VariableType_[numberOfVariables_];
    for (int var = 0; var < numberOfVariables_; var++){
      variableType_[var] = Enum.valueOf(VariableType_.class, solutionType) ;    
    } // for
  }

  /** 
  * Evaluates a solution 
  * @param solution The solution to evaluate
   * @throws JMException 
  */        
  public void evaluate(Solution solution) throws JMException {
    DecisionVariables gen  = solution.getDecisionVariables();

    double [] x = new double[numberOfVariables_];
    double [] f = new double[numberOfObjectives_];
    int k = numberOfVariables_ - numberOfObjectives_ + 1;
            
    for (int i = 0; i < numberOfVariables_; i++)
      x[i] = gen.variables_[i].getValue();
        
    //Calculate g
    double g = 0.0;
    for (int i = this.numberOfVariables_ - k; i < numberOfVariables_; i++)
      g += x[i] ;
        
    g = 1 + (9.0 * g) / k;
    //<-
                
    //Calculate the value of f1,f2,f3,...,fM-1 (take acount of vectors start at 0)
    for (int i = 0; i < numberOfObjectives_-1; i++)
      f[i] = x[i];
    //<-
        
    //->Calculate fM
    double h = 0.0;
    for (int i = 0; i < numberOfObjectives_ -1; i++)
      h += (f[i]/(1.0 + g))*(1 + Math.sin(3.0 * Math.PI * f[i]));
       
    h = numberOfObjectives_ - h;
        
    f[numberOfObjectives_-1] = (1 + g) * h;
    //<-
        
    //-> Setting up the value of the objetives
    for (int i = 0; i < numberOfObjectives_; i++)
      solution.setObjective(i,f[i]);        
    //<-
  } // evaluate
}