/** * TSP.java * * @author Antonio J. Nebro * @version 1.0 */package jmetal.problems.singleObjective;import jmetal.base.*;import jmetal.base.Configuration.SolutionType_;import jmetal.base.Configuration.VariableType_;import jmetal.base.variable.Binary;import jmetal.base.variable.Permutation;import java.io.* ;/** * Class representing a TSP (Traveling Salesman Problem) problem. */public class TSP extends Problem {  public int         numberOfCities_ ;   public double [][] distanceMatrix_ ;   /**  * Creates a new TSP problem instance. It accepts data files from TSPLIB  * @param filename The file containing the definition of the problem  */  public TSP(String filename) throws FileNotFoundException, IOException {    numberOfVariables_  = 1;    numberOfObjectives_ = 1;    numberOfConstraints_= 0;    problemName_        = "TSP";                 solutionType_ = SolutionType_.Permutation ;         variableType_ = new VariableType_[numberOfVariables_] ;    length_       = new int[numberOfVariables_];        variableType_[0] = Enum.valueOf(VariableType_.class, "Permutation") ;        readProblem(filename) ;    System.out.println(numberOfCities_) ;    length_      [0] = numberOfCities_ ;  } // TSP     /**   * Evaluates a solution   * @param solution The solution to evaluate  */        public void evaluate(Solution solution) {    double fitness   ;        fitness   = 0.0 ;    for (int i = 0; i < (numberOfCities_ - 1); i++) {      int x ;       int y ;            x = ((Permutation)solution.getDecisionVariables().variables_[0]).vector_[i] ;      y = ((Permutation)solution.getDecisionVariables().variables_[0]).vector_[i+1] ;//  cout << "I : " << i << ", x = " << x << ", y = " << y << endl ;          fitness += distanceMatrix_[x][y] ;    } // for    int firstCity ;    int lastCity  ;        firstCity = ((Permutation)solution.getDecisionVariables().variables_[0]).vector_[0] ;    lastCity  = ((Permutation)solution.getDecisionVariables().variables_[0]).vector_[numberOfCities_ - 1] ;    fitness += distanceMatrix_[firstCity][lastCity] ;        solution.setObjective(0, fitness);              } // evaluate  public void readProblem(String fileName) throws FileNotFoundException,                                                  IOException {    Reader inputFile = new BufferedReader(                       new InputStreamReader(                       new FileInputStream(fileName)));    StreamTokenizer token = new StreamTokenizer(inputFile);    try {      boolean found ;      found = false ;            token.nextToken();      while(!found) {        if ((token.sval != null) && ((token.sval.compareTo("DIMENSION") == 0)))          found = true ;        else          token.nextToken() ;      } // while      token.nextToken() ;      token.nextToken() ;            numberOfCities_ =  (int)token.nval ;      distanceMatrix_ = new double[numberOfCities_][numberOfCities_] ;      // Find the string SECTION        found = false ;      token.nextToken();      while(!found) {        if ((token.sval != null) &&           ((token.sval.compareTo("SECTION") == 0)))          found = true ;        else          token.nextToken() ;      } // while    // Read the data      double [] c = new double[2*numberOfCities_] ;      for (int i = 0; i < numberOfCities_; i++) {        token.nextToken() ;        int j = (int)token.nval ;        token.nextToken() ;        c[2*(j-1)] = token.nval ;        token.nextToken() ;        c[2*(j-1)+1] = token.nval ;      } // for      double dist ;      for (int k = 0; k < numberOfCities_; k++) {        distanceMatrix_[k][k] = 0;        for (int j = k + 1; j < numberOfCities_; j++) {          dist = Math.sqrt(Math.pow((c[k*2]-c[j*2]),2.0) +              Math.pow((c[k*2+1]-c[j*2+1]), 2));          dist = (int)(dist + .5);          distanceMatrix_[k][j] = dist;          distanceMatrix_[j][k] = dist;        } // for      } // for    } // try    catch (Exception e) {       System.err.println ("TSP.readProblem(): error when reading data file "+e);      System.exit(1);    } // catch  } // readProblem} // TSP