Struct EfsEval 

pub struct EfsEval {
    pub cost: f64,
    pub steps: Vec<f64>,
    pub beta: Option<Array1<f64>>,
    pub psi_gradient: Option<Array1<f64>>,
    pub psi_indices: Option<Vec<usize>>,
    pub inner_hessian_scale: Option<f64>,
    pub logdet_enclosure_gap: Option<f64>,
}

Result bundle returned by the EFS (extended Fellner–Schall) evaluation path. Pure data: families compute the additive step and the optional curvature/gradient diagnostics; the solver consumes them.

Fields

cost: f64

REML/LAML cost at the current rho (for convergence monitoring and comparing candidates).

steps: Vec<f64>

Additive steps. Length = n_rho + n_ext_coords.

For pure EFS: steps for non-penalty-like coordinates are 0.0. For hybrid EFS: ρ-coords get standard EFS multiplicative steps, ψ-coords get preconditioned gradient steps Δψ = -α G⁺ g_ψ.

beta: Option<Array1<f64>>

Current coefficient vector β̂ from the inner P-IRLS solve. Used by the EFS loop for the runtime barrier-curvature significance check when monotonicity constraints are present.

psi_gradient: Option<Array1<f64>>

Raw REML/LAML gradient restricted to the ψ block (design-moving coords).

Present only when the hybrid EFS strategy is active. Used by the outer iteration for backtracking on the ψ step: if the combined (ρ-EFS, ψ-gradient) step does not decrease V(θ), the ψ step size α is halved while keeping the ρ-EFS step fixed.

This avoids re-evaluating the gradient during backtracking since the gradient was already computed as part of the hybrid EFS eval.

psi_indices: Option<Vec<usize>>

Indices into the full θ vector that correspond to ψ (design-moving) coordinates. Used by the backtracking logic to selectively scale only the ψ portion of the step.

inner_hessian_scale: Option<f64>

Inner-Hessian curvature scale captured during the EFS eval, used to condition the ψ preconditioner across outer iterations.

logdet_enclosure_gap: Option<f64>

Logdet enclosure gap diagnostic (lower/upper bound spread) captured at this EFS evaluation when the bounded-logdet path is active.

Implementations

impl EfsEval

pub fn with_logdet_enclosure_gap(self, gap: Option<f64>) -> Self

Trait Implementations

impl Clone for EfsEval

fn clone(&self) -> EfsEval

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for EfsEval

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

Formats the value using the given formatter.