Enum SmoothLrReferenceSource 

pub enum SmoothLrReferenceSource {
    NullSpectrum,
    SpectralMomentMatch,
    UnitWeightFallback,
}

Which lane supplied a SmoothLrReferenceDf.

Variants

NullSpectrum

The statistic’s own null spectrum w, in full, scored by Imhof inversion of its characteristic function. This is the exact lane: the reference IS the null law, not a distribution fitted to some of its moments.

The spectrum is assembled from [H⁻¹]_jj and the term’s own λ-weighted penalty block through the symmetric similarity w_j = 1 − eig(B^{1/2} S_jj B^{1/2})² — see lr_tested_block for why that is the same spectrum as eig(2·F_jj − F_jj²) and why it is the better-conditioned way to reach it.

SpectralMomentMatch

[H⁻¹]_jj or the penalty block was unavailable, but the coefficient-influence matrix was, so only the first two moments of the spectrum are recoverable (tr A and tr A² for A = 2F_jj − F_jj², both traces of powers of one block). The reference is then the two-moment match g·χ²_ν.

It is EXACT at both ends of the shrinkage range and wrong in between, which is worth stating precisely because the ends are where the intuition goes. An unpenalized term has w ≡ 1 and the match is the textbook χ²_q; a term REML has shrunk to its null space has one weight of order one over a tail of dust — measured on a null-true k = 12 fit, w = (0.322, 5.9e-7, 7.1e-8, …) — and a single distinct weight is a scaled chi-square exactly. The gap opens at moderate shrinkage, where several weights are comparable and unequal: on f_j = 1/(1 + λγ_j) for a second-difference penalty at λ = 0.01, k = 20, the size delivered at a nominal α is 1.02× at 0.05, 1.11× at 0.01, 1.31× at 10⁻³ and 1.61× at 10⁻⁴ — one-signed, anti-conservative, and worse the deeper the tail.

It is a surrogate for the lane above, not a different claim about the statistic.

UnitWeightFallback

Neither the spectrum nor its moments were recoverable, so the reference falls back to the classical unit-weight shape χ²_{max(edf, null_dim, 1)} — every retained direction counted as if it were unpenalized. It is the only reference recoverable from a scalar EDF, and it is conservative for the same reason the whole pre-#2672 assembly was: unit weights over-state the statistic’s spread.

Trait Implementations

impl Clone for SmoothLrReferenceSource

fn clone(&self) -> SmoothLrReferenceSource

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for SmoothLrReferenceSource

impl Debug for SmoothLrReferenceSource

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

Formats the value using the given formatter.

impl Eq for SmoothLrReferenceSource

impl PartialEq for SmoothLrReferenceSource

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for SmoothLrReferenceSource