Struct SmoothCollectionGauge 

pub struct SmoothCollectionGauge {
    pub arm: SmoothCollectionGaugeArm,
    pub constraint_block: Array2<f64>,
    pub owner_terms: Vec<usize>,
    pub has_parametric_block: bool,
    pub local_identifiability_transform: Option<Array2<f64>>,
    pub local_columns: usize,
}

The COLLECTION’s gauge for one smooth term: the realized constraint block it was made orthogonal to, and which construction did it.

Why this is freezable, and why a term-local rebuild needs it

C = [intercept | owned linear axes | owner smooths' realized blocks] is a function of the data and of OTHER terms — never of this term’s own basis parameters. So C is invariant along an outer search over this term’s ψ (a length scale, a curvature, a measure-jet dial), while the two objects derived FROM it are not: T and R are both functions of the realized design, so both move with ψ.

That asymmetry is the whole content of gam#2747’s second half. The spatial outer search rebuilds one term LOCALLY per trial and splices the result into the collection design; a term-local build cannot see C, so before this existed the splice replaced the design and its chart while leaving the collection’s R behind, and the fit shipped X(ψ̂)·Z − C·R(ψ₀) — a block orthogonal to nothing, with ‖XᵀC‖/(‖X‖‖C‖) measured at 4.15e-1 against the 1e-8 bar the same step asserts whenever it applies a transform.

Carrying the ψ-INDEPENDENT half forward and re-deriving the ψ-dependent half is therefore not an optimization — it is the only formulation under which the criterion an outer search minimizes and the model the fit ships are the same object.

Fields

arm: SmoothCollectionGaugeArm

Which construction the collection chose.

constraint_block: Array2<f64>

C, n × q, exactly as build_constraint_block stacked it.

owner_terms: Vec<usize>

Indices into the collection’s smooth terms of the owner smooths whose realized designs joined C, in stack order. Recorded for the same reason ParametricResidualizationChart::owner_terms is.

has_parametric_block: bool

Whether the parametric block led C.

local_identifiability_transform: Option<Array2<f64>>

The TERM-LOCAL identifiability chart the gauged block was derived ON — z_local, before this gauge composed its own T on top of it (gam#2760).

The term’s BasisMetadata records the COMPOSITION z_local · T, which is what a predict-time replay wants: predict does not move ψ, so replaying the composed chart reproduces the fitted block exactly. A caller that DOES move ψ re-derives T here and must therefore rebuild in z_local, not in the composition — otherwise the collection’s orthogonalization is applied twice, once in the stale ψ₀ chart carried by the spec and once freshly by this gauge.

Measured before this existed, on a one-Duchon-term collection with C = [1] and the Delete arm: the replay spec carried FrozenTransform(12, 11), the doubly-charted rebuild had orthogonality residual 1.5e-12 at the fit’s own ℓ and 9.0e-1 one octave away, so the gauge resolved a direction and deleted a column at every ψ. The term reached the splice one column short and every κ fixture on a Duchon term refused in 0.2 s. On the Residualize arm the second application is idempotent, which is why the same defect was invisible on Matérn.

None means the term-local build applied no chart of its own — the usual case for the radial families, whose OrthogonalToParametric policy defers entirely to this gauge.

Like C and the arm, this is ψ-INDEPENDENT: it is a center-space constraint (1ᵀα = 0, a linear-orthogonality frame) or a frozen replay chart, never a function of the realized design.

local_columns: usize

The width of the TERM-LOCAL block this gauge was derived on, before the arm ran (gam#2760).

The collection’s realized width is this minus whatever the arm removed, and both halves are needed to read a rebuild that comes out narrow. A rebuild whose LOCAL width differs from this is not the same basis and is a defect; a rebuild that matches here and still comes out narrow after the arm has hit a ψ at which the realized design loses rank in this gauge’s chart — a statement about the trial point, not about the rebuild.

Trait Implementations

impl Clone for SmoothCollectionGauge

fn clone(&self) -> SmoothCollectionGauge

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SmoothCollectionGauge

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

Formats the value using the given formatter.