Struct GepDecoder 

pub struct GepDecoder;

The canonical Ferreira (2001) decoder: open-reading-frame scan, then level-order (breadth-first) tree construction.

Algorithm

1. ORF-length pass. A single left-to-right scan tracks the number of still-unfilled child slots, starting at 1 (the root). Each symbol fills one slot and opens arity new ones; the coding region ends when no slots remain. The tail-length constraint guarantees this terminates within the chromosome.
2. BFS child assignment. Because the coding prefix is already in level order, a node’s children are simply the next unread symbols. A running read cursor assigns each node arity contiguous children — no explicit queue is needed, since array order is BFS order.

Examples

use rlevo_evolution::algorithms::gep::{Alphabet, GenotypePhenotypeMap, GepDecoder};
use rlevo_evolution::function_set::ArithmeticFunctionSet;
use rlevo_evolution::rng::{seed_stream, SeedPurpose};

// A one-variable arithmetic alphabet (functions over a single `x`).
let alphabet = Alphabet::new(ArithmeticFunctionSet, 1, vec![]);

// Sample a valid head/tail genome: head loci draw any symbol, tail loci
// draw terminals only, with the tail sized per Ferreira (2001) eq. 3.4.
let mut rng = seed_stream(42, 0, SeedPurpose::Mutation);
let head_len = 3;
let tail_len = head_len * (alphabet.max_arity() - 1) + 1;
let mut genome = Vec::with_capacity(head_len + tail_len);
for _ in 0..head_len {
    genome.push(alphabet.sample_head_symbol(&mut rng));
}
for _ in 0..tail_len {
    genome.push(alphabet.sample_tail_symbol(&mut rng));
}

// Decode the linear chromosome into its expression-tree phenotype.
let tree = GepDecoder.decode(&alphabet, &genome);
assert!(tree.node_count() >= 1);

Trait Implementations

impl Clone for GepDecoder

fn clone(&self) -> GepDecoder

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for GepDecoder

impl Debug for GepDecoder

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for GepDecoder

fn default() -> GepDecoder

Returns the “default value” for a type.

impl<F: FunctionSet> GenotypePhenotypeMap<F> for GepDecoder

fn decode(&self, alphabet: &Alphabet<F>, genome: &[Symbol]) -> ExpressionTree

Decodes a chromosome into its phenotype.