/** {@inheritDoc} */
@Override
public void initialise(Problem problem) {
StructuredType harmony = problem.getDomain().getBuiltRepresenation().getClone();
harmony.randomize(new MersenneTwister());
setCandidateSolution(harmony);
this.getProperties().put(EntityType.FITNESS, InferiorFitness.instance());
}
/**
* This is an Synchronous strategy:
*
* <ol>
* <li>For all particles:
* <ol>
* <li>Update the particle velocity
* <li>Update the particle position
* </ol>
* <li>For all particles:
* <ol>
* <li>Calculate the particle fitness
* <li>For all particles in the current particle's neighbourhood:
* <ol>
* <li>Update the neighbourhood best
* </ol>
* </ol>
* </ol>
*
* @see
* net.sourceforge.cilib.PSO.IterationStrategy#performIteration(net.sourceforge.cilib.PSO.PSO)
* @param pso The {@link PSO} to have an iteration applied.
*/
@Override
public void performIteration(PSO pso) {
Topology<Particle> topology = pso.getTopology();
for (Particle current : topology) {
current.updateVelocity();
current.updatePosition(); // TODO: replace with visitor (will simplify particle interface)
boundaryConstraint.enforce(current);
}
Problem problem = AbstractAlgorithm.getAlgorithmList().get(0).getOptimisationProblem();
for (Particle current : topology) {
current.calculateFitness();
for (Particle other : topology.neighbourhood(current)) {
Particle p1 = current.getNeighbourhoodBest().getClone();
Particle p2 = other.getNeighbourhoodBest().getClone();
OptimisationSolution s1 =
new OptimisationSolution(
p1.getCandidateSolution().getClone(),
problem.getFitness(p1.getCandidateSolution().getClone()));
OptimisationSolution s2 =
new OptimisationSolution(
p2.getCandidateSolution().getClone(),
problem.getFitness(p2.getCandidateSolution().getClone()));
MOFitness fitness1 = (MOFitness) s1.getFitness();
MOFitness fitness2 = (MOFitness) s2.getFitness();
// System.out.println("fitness1 = ");
// for (int i=0; i < fitness1.getDimension(); i++)
// System.out.println(fitness1.getFitness(i).getValue());
//
// System.out.println("fitness2 = ");
// for (int i=0; i < fitness2.getDimension(); i++)
// System.out.println(fitness2.getFitness(i).getValue());
if (fitness1.compareTo(fitness2) > 0) {
other.setNeighbourhoodBest(current);
}
}
}
}
/**
* Splits up the given {@link OptimisationProblem} into sub-problems, where each sub problem
* contains a sequencial (non-uniform sized) portion of the problem vector, and assigns them to
* all the participating {@link Algorithm}s. This implementation assigns a portion of length
* equals to dimensionality/number of populations + 1 to dimensionality % number of populations of
* the participating algorithms.
*
* @param populations The list of participating {@linkplain PopulationBasedAlgorithm}s.
* @param problem The problem that needs to be re-distributed.
* @param context The context vector maintained by the {@linkplain
* CooperativeCoevolutionAlgorithm}.
*/
public void performDistribution(
List<PopulationBasedAlgorithm> populations, Problem problem, Vector context) {
checkArgument(
populations.size() >= 2,
"There should at least be two Cooperating populations in a Cooperative Algorithm");
int dimension = problem.getDomain().getDimension() / populations.size();
int oddDimensions = problem.getDomain().getDimension() % populations.size();
int i = 0;
int offset = 0;
for (Algorithm population : populations) {
int actualDimension = dimension;
if (i < oddDimensions) actualDimension++;
DimensionAllocation problemAllocation =
new SequencialDimensionAllocation(offset, actualDimension);
population.setOptimisationProblem(
new CooperativeCoevolutionProblemAdapter(problem, problemAllocation, context));
offset += actualDimension;
++i;
}
}