Struct TrustRegionConfig 

pub struct TrustRegionConfig {
    pub ftol: f64,
    pub xtol: f64,
    pub gtol: f64,
    pub max_nfev: usize,
    pub delta0: f64,
    pub max_delta: f64,
    pub eta: f64,
}

Tuning for a single Δ-radius trust-region solve.

Fields

ftol: f64

Relative cost-decrease tolerance.

xtol: f64

Relative step-size tolerance.

gtol: f64

Gradient infinity-norm tolerance.

max_nfev: usize

Maximum residual evaluations.

delta0: f64

Initial trust radius Δ (scaled units); ≤ 0 ⇒ a problem-derived default.

max_delta: f64

Hard upper bound on Δ.

eta: f64

Acceptance threshold: accept the step when ρ > eta.

Must be < 0.25 (debug-asserted in minimize_tr). The Δ update shrinks the radius only when ρ < 0.25, so an eta ≥ 0.25 opens a band ρ ∈ [0.25, eta] in which a step is rejected while Δ is left unchanged — the accept/reject subloop then re-solves the identical subproblem at the identical radius until the evaluation budget runs out.

The debug_assert! above does not run in release builds, so this crate does not itself enforce the bound outside cfg(debug_assertions) — callers must validate eta before constructing this config. spectrafit-solver::dispatch does, rejecting eta >= 0.25 (or non-finite / negative eta) with SolverError::InvalidEta before it reaches this driver.

Trait Implementations

impl Clone for TrustRegionConfig

fn clone(&self) -> TrustRegionConfig

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for TrustRegionConfig

impl Debug for TrustRegionConfig

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

Formats the value using the given formatter.

impl Default for TrustRegionConfig

fn default() -> Self

Returns the “default value” for a type.