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