mtg-genetic-deckbuilding

commit 62f5f0a3fdec531acab281180a79e9f0fa9add89
parent 30338046d9c1c07e54e6e78bd266e9955befd136
Author: Kevin Corvisier <git@kevincorvisier.fr>
Date:   Thu, 19 Dec 2024 12:17:40 +0900

Make Selection.select return a Pair instead of a List

Diffstat:
M
src/main/java/fr/kevincorvisier/mtg/gdb/operators/selection/Selection.java
 | 
6
+++---
M
src/main/java/fr/kevincorvisier/mtg/gdb/population/NextGenerationService.java
 | 
9
++++-----

2 files changed, 7 insertions(+), 8 deletions(-)
diff --git a/src/main/java/fr/kevincorvisier/mtg/gdb/operators/selection/Selection.java b/src/main/java/fr/kevincorvisier/mtg/gdb/operators/selection/Selection.java
@@ -1,6 +1,6 @@
 package fr.kevincorvisier.mtg.gdb.operators.selection;
 
-import java.util.List;
+import org.apache.commons.math3.util.Pair;
 
 import fr.kevincorvisier.mtg.gdb.population.Individual;
 import fr.kevincorvisier.mtg.gdb.population.Population;
@@ -10,7 +10,7 @@ public abstract class Selection
 	/**
 	 * Select two individuals from a population for reproduction
 	 */
-	public List<Individual> select(final Population population)
+	public Pair<Individual, Individual> select(final Population population)
 	{
 		final Individual parent1 = selectOne(population);
 		Individual parent2;
@@ -21,7 +21,7 @@ public abstract class Selection
 			parent2 = selectOne(population);
 		} while (parent1 == parent2);
 
-		return List.of(parent1, parent2);
+		return Pair.create(parent1, parent2);
 	}
 
 	protected abstract Individual selectOne(final Population population);
diff --git a/src/main/java/fr/kevincorvisier/mtg/gdb/population/NextGenerationService.java b/src/main/java/fr/kevincorvisier/mtg/gdb/population/NextGenerationService.java
@@ -2,9 +2,8 @@ package fr.kevincorvisier.mtg.gdb.population;
 
 import java.util.Collection;
 import java.util.HashSet;
-import java.util.List;
-import java.util.stream.Collectors;
 
+import org.apache.commons.math3.util.Pair;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.stereotype.Service;
 
@@ -80,11 +79,11 @@ public class NextGenerationService
 		while (next.getSize() < maximumSize)
 		{
 			// Selection
-			final List<Individual> parents = selection.select(population);
-			final double estimatedFitness = parents.stream().collect(Collectors.averagingDouble(Individual::getFitness));
+			final Pair<Individual, Individual> parents = selection.select(population);
+			final double estimatedFitness = (parents.getFirst().getFitness() + parents.getSecond().getFitness()) / 2d;
 
 			// Crossover
-			for (final Individual child : crossover.crossover(parents.get(0), parents.get(1)))
+			for (final Individual child : crossover.crossover(parents.getFirst(), parents.getSecond()))
 			{
 				if (result.size() >= maximumSize)
 					continue; // Ensure second child will not breach the population limit