Struct PolynomialMutation 

pub struct PolynomialMutation {
    pub eta_m: f64,
    pub mutation_probability: Option<f64>,
    pub unbounded_sigma: Option<f64>,
}

Polynomial mutation (bounded)

Uses the polynomial probability distribution to perturb genes. Respects bounds and is commonly used with NSGA-II.

Reference: Deb, K. (2001). Multi-Objective Optimization using Evolutionary Algorithms.

Fields

eta_m: f64

Distribution index (typically 20-100) Higher values = smaller mutations

mutation_probability: Option<f64>

Per-gene mutation probability (default: 1/n)

unbounded_sigma: Option<f64>

Standard deviation used by the unbounded fallback (see MutationOperator::mutate). None selects the adaptive default 0.1 * (1 + |x|) per gene; Some(s) uses a fixed s.

Implementations

impl PolynomialMutation

pub fn new(eta_m: f64) -> Self

Create a new polynomial mutation with the given distribution index

pub fn with_probability(self, probability: f64) -> Self

Set a fixed mutation probability per gene

pub fn with_unbounded_sigma(self, sigma: f64) -> Self

Set the standard deviation of the unbounded Gaussian fallback.

Polynomial mutation is only defined relative to finite bounds; when the operator is invoked without bounds it perturbs each gene with Gaussian noise instead (audit EV-102). By default the per-gene sigma is 0.1 * (1 + |x|); this method pins it to a fixed value.

Trait Implementations

impl BoundedMutationOperator<RealVector> for PolynomialMutation

fn mutate_bounded<R: Rng>( &self, genome: &mut RealVector, bounds: &MultiBounds, rng: &mut R, )

Apply bounded mutation to a genome

impl Clone for PolynomialMutation

fn clone(&self) -> PolynomialMutation

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for PolynomialMutation

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

Formats the value using the given formatter.

impl MutationOperator<RealVector> for PolynomialMutation

fn mutate<R: Rng>(&self, genome: &mut RealVector, rng: &mut R)

Apply mutation to a genome in place

fn mutation_probability(&self) -> Option<f64>

Report the per-gene mutation probability actually applied by this operator.

impl TunableMutation for PolynomialMutation

fn set_mutation_probability(&mut self, probability: f64)

Set the per-gene mutation probability applied by subsequent mutate calls.