protoas/Pheromone.java

   1 package protoas;
   2
   3 class Pheromone {
   4
   5   protected Graph graph;
   6   protected double[][] Pheromone;
   7
   8   Pheromone(Graph graph) {
   9     this.graph = graph;
  10     this.Pheromone = new double[graph.getNumOfCities()][graph.getNumOfCities()];
  11
  12     double tauzero =
  13       (double)(graph.getNumOfCities()) /
  14       graph.nearestNeighbourHeuristicRandomStart();
  15
  16     for (int i = 0; i < graph.getNumOfCities(); i++) {
  17       for (int j = 0; j < graph.getNumOfCities(); j++) {
  18         setPheromone(i,j, tauzero);
  19       }
  20     }
  21
  22   }
  23
  24   public void pheromoneUpdate(Ant[] ants) {
  25     evaporate();
  26
  27     for (Ant ant : ants) {
  28       depositPheromone(ant);
  29     }
  30
  31     graph.computeChoiceInformation();
  32   }
  33
  34   public void evaporate() {
  35     for (int i = 1; i < graph.getNumOfCities(); i++) {
  36       for (int j = 1; j < graph.getNumOfCities(); j++) {
  37         Pheromone[i][j] = (1.0 - graph.getROH()) * Pheromone[i][j];
  38         Pheromone[j][i] = Pheromone[i][j];
  39       }
  40     }
  41   }
  42
  43   public void depositPheromone(Ant ant) {
  44     double dt = 1.0/ant.getTourLength();
  45     int j = 0;
  46     int l = 0;
  47     for (int i = 0; i < graph.getNumOfCities() - 1; i++) {
  48       j = ant.getTour(i);
  49       l = ant.getTour(i+1);
  50       Pheromone[j][l] = Pheromone[j][l] + dt;
  51       Pheromone[l][j] = Pheromone[j][l];
  52     }
  53   }
  54
  55   public double[][] getPheromone() {
  56     return this.Pheromone;
  57   }
  58
  59   public double getPheromone(int x, int y) {
  60     return this.Pheromone[x][y];
  61   }
  62
  63   public void setPheromone(double[][] Pheromone) {
  64     this.Pheromone = Pheromone;
  65   }
  66
  67   public void setPheromone(int x, int y, double Pheromone) {
  68     this.Pheromone[x][y] = Pheromone;
  69   }
  70
  71 }