1 package net.bmahe.genetics4j.core.combination.singlepointcrossover;
2
3 import java.util.BitSet;
4 import java.util.List;
5 import java.util.Objects;
6 import java.util.random.RandomGenerator;
7
8 import org.apache.commons.lang3.Validate;
9
10 import net.bmahe.genetics4j.core.chromosomes.BitChromosome;
11 import net.bmahe.genetics4j.core.chromosomes.Chromosome;
12 import net.bmahe.genetics4j.core.combination.ChromosomeCombinator;
13 import net.bmahe.genetics4j.core.spec.AbstractEAConfiguration;
14
15 public class BitChromosomeSinglePointCrossover<T extends Comparable<T>> implements ChromosomeCombinator<T> {
16
17 private final RandomGenerator randomGenerator;
18
19 public BitChromosomeSinglePointCrossover(final RandomGenerator _randomGenerator) {
20 Objects.requireNonNull(_randomGenerator);
21
22 this.randomGenerator = _randomGenerator;
23 }
24
25 @Override
26 public List<Chromosome> combine(final AbstractEAConfiguration<T> eaConfiguration, final Chromosome chromosome1,
27 final T firstParentFitness, final Chromosome chromosome2, final T secondParentFitness) {
28 Objects.requireNonNull(chromosome1);
29 Objects.requireNonNull(chromosome2);
30 Validate.isInstanceOf(BitChromosome.class, chromosome1);
31 Validate.isInstanceOf(BitChromosome.class, chromosome2);
32 Validate.isTrue(chromosome1.getNumAlleles() == chromosome2.getNumAlleles());
33
34 final int alleleSplit = randomGenerator.nextInt(chromosome1.getNumAlleles());
35
36 final BitChromosome bitChromosome1 = (BitChromosome) chromosome1;
37 final BitChromosome bitChromosome2 = (BitChromosome) chromosome2;
38
39 final int numAlleles = chromosome1.getNumAlleles();
40 final BitSet firstChildBitSet = new BitSet(numAlleles);
41 final BitSet secondChildBitSet = new BitSet(numAlleles);
42
43 for (int i = 0; i < alleleSplit; i++) {
44 firstChildBitSet.set(i, bitChromosome1.getBit(i));
45 secondChildBitSet.set(i, bitChromosome2.getBit(i));
46 }
47 for (int i = alleleSplit; i < numAlleles; i++) {
48 firstChildBitSet.set(i, bitChromosome2.getBit(i));
49 secondChildBitSet.set(i, bitChromosome1.getBit(i));
50 }
51
52 return List.of(new BitChromosome(numAlleles, firstChildBitSet), new BitChromosome(numAlleles, secondChildBitSet));
53 }
54 }