Pheromone.java

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