Enum CoveragePolicy 

pub enum CoveragePolicy {
    Full,
    TopK {
        k: usize,
    },
}

Determines which population members are refined each generation.

Cost and tuning

Coverage is the dominant cost knob: each refined row spends up to Params::max_iters fitness evaluations, so Full costs pop_size× a TopK { k: 1 } generation. When the budget that matters is evaluations to reach a target (not wall-clock or final-gen fitness), wide coverage with a heavy searcher can lose to bare evolution: it spends its eval budget polishing individuals that selection would have discarded anyway. Tune against evals-to-target, not against a fixed generation count — a fixed-gens comparison hides the refinement evals and flatters wide coverage. The default, TopK { k: 1 }, refines only the single best individual and is the cheapest sane starting point.

One caveat cuts the other way: on a separable landscape with basin-width search steps, axis-aligned hill climbing is nearly a direct solver, so wide coverage with an untuned high-max_iters searcher can dominate. That is a landscape artifact, not a config to copy — re-tune per problem.

The wrapper avoids the seeding-eval waste that an unaware caller would pay: it hands each searcher the fitness the harness already computed via LocalSearch::refine_with_known_fitness, so a refined row spends its evals on probes rather than re-scoring its own input (ADR 0016 reversal criteria).

Variants

Full

Refine every individual.

TopK

Refine only the k fittest (largest-fitness, canonical maximise) individuals, ties broken by lower index. k is clamped to the population size.

Fields

k: usize

Number of fittest individuals to refine.

Trait Implementations

impl Clone for CoveragePolicy

fn clone(&self) -> CoveragePolicy

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for CoveragePolicy

impl Debug for CoveragePolicy

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

Formats the value using the given formatter.

impl Default for CoveragePolicy

fn default() -> Self

Returns the “default value” for a type.

impl Eq for CoveragePolicy

impl PartialEq for CoveragePolicy

fn eq(&self, other: &CoveragePolicy) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for CoveragePolicy