1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56

use super::Mutations;
use crate::{genome::Genome, rng::GenomeRng};

impl Mutations {
    /// This mutation alters `percent_perturbed` connection weights with perturbations sampled from calls to [`GenomeRng::weight_perturbation`].
    pub fn change_weights(percent_perturbed: f64, genome: &mut Genome, rng: &mut GenomeRng) {
        let change_feed_forward_amount =
            (percent_perturbed * genome.feed_forward.len() as f64).ceil() as usize;
        let change_recurrent_amount =
            (percent_perturbed * genome.recurrent.len() as f64).ceil() as usize;

        genome.feed_forward = genome
            .feed_forward
            .drain_into_random(rng)
            .enumerate()
            .map(|(index, mut connection)| {
                if index < change_feed_forward_amount {
                    connection.weight = rng.weight_perturbation(connection.weight);
                }
                connection
            })
            .collect();

        genome.recurrent = genome
            .recurrent
            .drain_into_random(rng)
            .enumerate()
            .map(|(index, mut connection)| {
                if index < change_recurrent_amount {
                    connection.weight = rng.weight_perturbation(connection.weight);
                }
                connection
            })
            .collect();
    }
}

#[cfg(test)]
mod tests {
    use crate::GenomeContext;

    #[test]
    fn change_weights() {
        let mut gc = GenomeContext::default();

        let mut genome = gc.initialized_genome();

        let old_weight = genome.feed_forward.iter().next().unwrap().weight;

        genome.change_weights_with_context(&mut gc);

        assert!(
            (old_weight - genome.feed_forward.iter().next().unwrap().weight).abs() > f64::EPSILON
        );
    }
}