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use rand::Rng;
use crate::{Genome, Mutations};
impl Mutations {
pub fn remove_node(genome: &mut Genome, rng: &mut impl Rng) -> Result<(), &'static str> {
if let Some(removable_node) = &genome
.hidden
.iter()
.cycle()
.skip((rng.gen::<f64>() * (genome.hidden.len()) as f64).floor() as usize)
.take(genome.hidden.len())
.find(|removal_candidate| {
genome
.connections()
.filter_map(|connection| {
if connection.output == removal_candidate.id {
Some(connection.input)
} else {
None
}
})
.all(|id| genome.has_alternative_output(id, removal_candidate.id))
&& genome
.connections()
.filter_map(|connection| {
if connection.input == removal_candidate.id {
Some(connection.output)
} else {
None
}
})
.all(|id| genome.has_alternative_input(id, removal_candidate.id))
})
.cloned()
{
genome.feed_forward.retain(|connection| {
connection.input != removable_node.id && connection.output != removable_node.id
});
genome.recurrent.retain(|connection| {
connection.input != removable_node.id && connection.output != removable_node.id
});
assert!(genome.hidden.remove(removable_node));
Ok(())
} else {
Err("could not find removable node")
}
}
}
#[cfg(test)]
mod tests {
use crate::{
activations::Activation,
genes::{Connection, Genes, Id, Node},
Genome, GenomeContext,
};
#[test]
fn can_remove_node() {
let mut gc = GenomeContext::default();
let mut genome = Genome {
inputs: Genes(
vec![Node::new(Id(0), Activation::Linear)]
.iter()
.cloned()
.collect(),
),
hidden: Genes(
vec![
Node::new(Id(2), Activation::Linear),
Node::new(Id(3), Activation::Linear),
]
.iter()
.cloned()
.collect(),
),
outputs: Genes(
vec![Node::new(Id(1), Activation::Linear)]
.iter()
.cloned()
.collect(),
),
feed_forward: Genes(
vec![
Connection::new(Id(0), 1.0, Id(2)),
Connection::new(Id(0), 1.0, Id(3)),
Connection::new(Id(2), 1.0, Id(1)),
Connection::new(Id(3), 1.0, Id(1)),
]
.iter()
.cloned()
.collect(),
),
..Default::default()
};
assert!(genome.remove_node_with_context(&mut gc).is_ok())
}
#[test]
fn can_not_remove_node() {
let mut gc = GenomeContext::default();
let mut genome = Genome {
inputs: Genes(
vec![Node::new(Id(0), Activation::Linear)]
.iter()
.cloned()
.collect(),
),
hidden: Genes(
vec![Node::new(Id(2), Activation::Linear)]
.iter()
.cloned()
.collect(),
),
outputs: Genes(
vec![Node::new(Id(1), Activation::Linear)]
.iter()
.cloned()
.collect(),
),
feed_forward: Genes(
vec![
Connection::new(Id(0), 1.0, Id(2)),
Connection::new(Id(2), 1.0, Id(1)),
]
.iter()
.cloned()
.collect(),
),
..Default::default()
};
assert!(!genome.remove_node_with_context(&mut gc).is_ok())
}
}