radiate_alters/crossovers/
simulated_binary.rs

1use radiate_core::{
2    AlterResult, BoundedGene, Chromosome, Crossover, Gene, Rate, Valid, random_provider,
3};
4use radiate_utils::Float;
5
6const NAME: &str = "sbx_crossover";
7
8pub struct SimulatedBinaryCrossover {
9    crossover_rate: Rate,
10    contiguty: f32,
11}
12
13impl SimulatedBinaryCrossover {
14    pub fn new(crossover_rate: impl Into<Rate>, contiguty: f32) -> Self {
15        let crossover_rate = crossover_rate.into();
16        if !crossover_rate.is_valid() {
17            panic!("Rate {crossover_rate:?} is not valid. Must be between 0.0 and 1.0",);
18        }
19        Self {
20            contiguty,
21            crossover_rate,
22        }
23    }
24}
25
26impl<A, G, C> Crossover<C> for SimulatedBinaryCrossover
27where
28    A: Float,
29    G: Gene<Allele = A> + BoundedGene,
30    C: Chromosome<Gene = G>,
31{
32    fn name(&self) -> String {
33        NAME.to_string()
34    }
35
36    fn rate(&self) -> Rate {
37        self.crossover_rate.clone()
38    }
39
40    #[inline]
41    fn cross_chromosomes(&self, chrom_one: &mut C, chrom_two: &mut C, _: f32) -> AlterResult {
42        let length = std::cmp::min(chrom_one.len(), chrom_two.len());
43
44        if length < 2 {
45            return AlterResult::empty();
46        }
47
48        let mut count = 0;
49
50        random_provider::with_rng(|rand| {
51            let one_slice = chrom_one.as_mut_slice();
52            let two_slice = chrom_two.as_slice();
53            for i in 0..length {
54                if rand.bool(0.5) {
55                    let u = rand.random::<f32>();
56                    let beta = A::from(if u <= 0.5 {
57                        (2.0 * u).powf(1.0 / (self.contiguty + 1.0))
58                    } else {
59                        (0.5 / (1.0 - u)).powf(1.0 / (self.contiguty + 1.0))
60                    })
61                    .unwrap();
62
63                    let v1 = one_slice[i].allele().clone();
64                    let v2 = two_slice[i].allele().clone();
65
66                    let v = if rand.bool(0.5) {
67                        ((v1 - v2) * A::HALF) - (beta * A::HALF * (v1 - v2).abs())
68                    } else {
69                        ((v1 - v2) * A::HALF) + (beta * A::HALF * (v1 - v2).abs())
70                    };
71
72                    let (one_min, one_max) = one_slice[i].bounds();
73                    let new_gene = v.clamp(*one_min, *one_max);
74
75                    count += 1;
76
77                    *one_slice[i].allele_mut() = new_gene;
78                }
79            }
80        });
81
82        AlterResult::from(count)
83    }
84}
radiate_alters/crossovers/simulated_binary.rs

radiate_alters/crossovers/
simulated_binary.rs
