コード例 #1
0
 /**
  * Respond to the environment change and ensure that the neighbourhood best entities are updated.
  * This method (Template Method) calls two other methods in turn:
  *
  * <ul>
  *   <li>{@link #performReaction(PopulationBasedAlgorithm)}
  *   <li>{@link #updateNeighbourhoodBestEntities(Topology)}
  * </ul>
  *
  * @param algorithm some {@link PopulationBasedAlgorithm population based algorithm}
  */
 public <P extends Particle, A extends SinglePopulationBasedAlgorithm<P>> void respond(
     A algorithm) {
   performReaction(algorithm);
   if (hasMemory) {
     updateNeighbourhoodBestEntities(algorithm.getTopology(), algorithm.getNeighbourhood());
   }
 }
コード例 #2
0
  /**
   * After every {@link #interval} iteration, pick {@link #numberOfSentries a number of} random
   * entities from the given {@link Algorithm algorithm's} topology and compare their previous
   * fitness values with their current fitness values. An environment change is detected when the
   * difference between the previous and current fitness values are &gt;= the specified {@link
   * #epsilon} value.
   *
   * @param algorithm used to get hold of topology of entities and number of iterations
   * @return true if a change has been detected, false otherwise
   */
  @Override
  public <A extends HasTopology & Algorithm & HasNeighbourhood> boolean detect(A algorithm) {
    if ((AbstractAlgorithm.get().getIterations() % interval == 0)
        && (AbstractAlgorithm.get().getIterations() != 0)) {
      List all = Java.List_ArrayList().f(algorithm.getTopology());

      for (int i = 0; i < numberOfSentries.getParameter(); i++) {
        // select random sentry entity
        int random = Rand.nextInt(all.size());
        StandardParticle sentry = (StandardParticle) all.get(random);

        // check for change
        // double previousFitness = sentry.getFitness().getValue();

        boolean detectedChange = false;

        if (sentry.getFitness().getClass().getName().matches("MinimisationFitness")) {
          Fitness previousFitness = sentry.getFitness();
          sentry.calculateFitness();
          Fitness currentFitness = sentry.getFitness();

          if (Math.abs(previousFitness.getValue() - currentFitness.getValue()) >= epsilon) {
            detectedChange = true;
          }
        } else if (sentry.getFitness().getClass().getName().matches("StandardMOFitness")) {
          MOFitness previousFitness = (MOFitness) sentry.getFitness();
          sentry.calculateFitness();
          MOFitness currentFitness = (MOFitness) sentry.getFitness();

          for (int k = 0; k < previousFitness.getDimension(); k++)
            if (Math.abs(
                    previousFitness.getFitness(k).getValue()
                        - currentFitness.getFitness(k).getValue())
                >= epsilon) {
              detectedChange = true;
              break;
            }
        }
        if (detectedChange) {
          System.out.println("Detected a change");
          return true;
        }

        // remove the selected element from the all list preventing it from being selected again
        all.remove(random);
      }
    }
    return false;
  }