1 files changed, 91 insertions, 8 deletions

diff --git a/src/jcgp/backend/modules/es/TournamentSelection.java b/src/jcgp/backend/modules/es/TournamentSelection.java
index 7cc9706..43fea81 100644
--- a/src/jcgp/backend/modules/es/TournamentSelection.java
+++ b/src/jcgp/backend/modules/es/TournamentSelection.java
@@ -1,35 +1,118 @@
 package jcgp.backend.modules.es;
 
+import java.util.Arrays;
+
 import jcgp.backend.modules.mutator.Mutator;
+import jcgp.backend.population.Chromosome;
 import jcgp.backend.population.Population;
 import jcgp.backend.resources.Resources;
+import jcgp.backend.resources.parameters.BooleanParameter;
 import jcgp.backend.resources.parameters.IntegerParameter;
 import jcgp.backend.resources.parameters.Parameter;
+import jcgp.backend.resources.parameters.ParameterStatus;
 
+/**
+ * Tournament selection
+ * <br><br>
+ * This strategy generates a new population by selecting a specified number
+ * of chromosomes from the original population and selecting the fittest out
+ * of the isolated subset (the tournament). The selected individual is mutated
+ * using the specified mutator. This process is repeated until the new population
+ * is complete.
+ * <br><br>
+ * One integer parameter is used to control this strategy: tournament
+ * size. This must always be greater than 0 and smaller than or equal to the
+ * population size. Setting it to equal population size results in the same
+ * chromosome being selected for every tournament, and setting it to 1 leads
+ * to an effectively random search.
+ * <br>
+ * One additional parameter, report, controls whether a detailed log of the
+ * algorithm's operation is to be printed or not. Reports respect the report
+ * interval base parameter.
+ * 
+ * @see EvolutionaryStrategy
+ * @author Eduardo Pedroni
+ *
+ */
 public class TournamentSelection implements EvolutionaryStrategy {
 	
 	private IntegerParameter tournamentSize;
+	private BooleanParameter report;
 	
-	public TournamentSelection(Resources resources) {		
+	/**
+	 * Creates a new instance of TournamentSelection. 
+	 * 
+	 * @param resources a reference to the experiment's resources.
+	 */
+	public TournamentSelection(final Resources resources) {		
 		tournamentSize = new IntegerParameter(1, "Tournament size") {
 			@Override
 			public void validate(Number newValue) {
-				// TODO this
+				if (newValue.intValue() <= 0) {
+					status = ParameterStatus.INVALID;
+					status.setDetails("Tournament size must be greater than 0.");
+				} else if (newValue.intValue() > resources.populationSize()) {
+					status = ParameterStatus.INVALID;
+					status.setDetails("Tournament size must not be greater than the population size.");
+				} else if (newValue.intValue() == 1) {
+					status = ParameterStatus.WARNING;
+					status.setDetails("A tournament size of 1 results in a random search.");
+				} else if (newValue.intValue() == resources.populationSize()) {
+					status = ParameterStatus.WARNING;
+					status.setDetails("A tournament size equal to population size results in the same individual being selected every time.");
+				} else {
+					status = ParameterStatus.VALID;
+				}
+			}
+		};
+		report = new BooleanParameter(false, "Report") {
+			@Override
+			public void validate(Boolean newValue) {
+				// blank
 			}
 		};
 	}
 
 	@Override
 	public Parameter<?>[] getLocalParameters() {
-		return new Parameter[] {tournamentSize};
+		return new Parameter[] {tournamentSize, report};
 	}
 
 	@Override
-	public void evolve(Population population, Mutator mutator,
-			Resources parameters) {
-		tournamentSize.set(tournamentSize.get() + 1);
-		// TODO implement this
-
+	public void evolve(Population population, Mutator mutator, Resources resources) {
+		/* Create an entirely new population by isolating random subsets of
+		 * the original population and choosing the fittest individual within
+		 * that subset. Each chosen individual is mutated and copied back into the
+		 * population.
+		 */
+		Chromosome[] newPopulation = new Chromosome[resources.populationSize()];
+		
+		// start by selecting all of the chromosomes that will be promoted
+		for (int i = 0; i < resources.populationSize(); i++) {
+			if (report.get()) resources.reportln("[ES] Starting tournament " + i);
+			
+			/* the population is sorted in ascending order of fitness,
+			 * meaning the higher the index of the contender, the fitter
+			 * it is
+			 */
+			int[] contenders = new int[tournamentSize.get()];
+			for (int t = 0; t < tournamentSize.get() - 1; t++) {
+				contenders[t] = resources.getRandomInt(resources.populationSize());
+			}
+			if (report.get()) resources.reportln("[ES] Selected contenders: " + Arrays.toString(contenders));
+			Arrays.sort(contenders);
+			if (report.get()) resources.reportln("[ES] Chr " + contenders[contenders.length - 1] + " wins the tournament, copying and mutating...");
+			// create a copy of the selected chromosome and mutate it
+			newPopulation[i] = new Chromosome(population.getChromosome(contenders[contenders.length - 1]));
+			mutator.mutate(newPopulation[i], resources);
+		}
+		if (report.get()) resources.reportln("[ES] Tournaments are finished, copying new chromosomes into population");
+		// newPopulation has been generated, copy into the population
+		for (int c = 0; c < resources.populationSize(); c++) {
+			population.getChromosome(c).copyGenes(newPopulation[c]);
+		}
+		
+		if (report.get()) resources.reportln("[ES] Generation is complete");
 	}
 	
 	@Override