1 package net.bmahe.genetics4j.core.combination.singlepointarithmetic;
2
3 import java.util.List;
4 import java.util.Objects;
5 import java.util.random.RandomGenerator;
6
7 import org.apache.commons.lang3.Validate;
8
9 import net.bmahe.genetics4j.core.chromosomes.Chromosome;
10 import net.bmahe.genetics4j.core.chromosomes.DoubleChromosome;
11 import net.bmahe.genetics4j.core.combination.ChromosomeCombinator;
12 import net.bmahe.genetics4j.core.spec.AbstractEAConfiguration;
13
14 public class DoubleChromosomeSinglePointArithmetic<T extends Comparable<T>> implements ChromosomeCombinator<T> {
15
16 private final RandomGenerator randomGenerator;
17 private final double alpha;
18
19 public DoubleChromosomeSinglePointArithmetic(final RandomGenerator _randomGenerator, final double _alpha) {
20 Objects.requireNonNull(_randomGenerator);
21 Validate.inclusiveBetween(0.0d, 1.0d, _alpha);
22
23 this.randomGenerator = _randomGenerator;
24 this.alpha = _alpha;
25 }
26
27 @Override
28 public List<Chromosome> combine(final AbstractEAConfiguration<T> eaConfiguration, final Chromosome chromosome1,
29 final T firstParentFitness, final Chromosome chromosome2, final T secondParentFitness) {
30 Objects.requireNonNull(chromosome1);
31 Objects.requireNonNull(chromosome2);
32 Validate.isInstanceOf(DoubleChromosome.class, chromosome1);
33 Validate.isInstanceOf(DoubleChromosome.class, chromosome2);
34 Validate.isTrue(chromosome1.getNumAlleles() == chromosome2.getNumAlleles());
35
36 final int alleleSplit = randomGenerator.nextInt(chromosome1.getNumAlleles());
37
38 final DoubleChromosome intChromosome1 = (DoubleChromosome) chromosome1;
39 final DoubleChromosome intChromosome2 = (DoubleChromosome) chromosome2;
40
41 final int numAlleles = chromosome1.getNumAlleles();
42 final double[] firstChildValues = new double[numAlleles];
43 final double[] secondChildValues = new double[numAlleles];
44
45 for (int i = 0; i < numAlleles; i++) {
46
47 final double firstAllele = intChromosome1.getAllele(i);
48 final double secondAllele = intChromosome2.getAllele(i);
49
50 if (i < alleleSplit) {
51 firstChildValues[i] = alpha * firstAllele + (1 - alpha) * secondAllele;
52 secondChildValues[i] = (1 - alpha) * firstAllele + alpha * secondAllele;
53 } else {
54 firstChildValues[i] = (1 - alpha) * firstAllele + alpha * secondAllele;
55 secondChildValues[i] = alpha * firstAllele + (1 - alpha) * secondAllele;
56 }
57 }
58
59 return List.of(
60 new DoubleChromosome(numAlleles,
61 intChromosome1.getMinValue(),
62 intChromosome1.getMaxValue(),
63 firstChildValues),
64 new DoubleChromosome(numAlleles,
65 intChromosome1.getMinValue(),
66 intChromosome1.getMaxValue(),
67 secondChildValues));
68 }
69 }