Struct KroneckerInvariantStructure 

pub struct KroneckerInvariantStructure {
    pub marginal_eigenvalues: Arc<Vec<Array1<f64>>>,
    pub marginal_qs: Arc<Vec<Array2<f64>>>,
    pub reparameterized_marginals: Arc<Vec<Array2<f64>>>,
    pub max_balanced_eigenvalue: f64,
}

λ-invariant Kronecker tensor structure: everything in a tensor-product fit that depends ONLY on the marginal designs/penalties (which are fixed for the whole fit) and NOT on the smoothing parameters λ = exp(ρ).

The marginal eigendecomposition (O(Σ q_k³)), the reparameterized marginals B_k · U_k, and the balanced-penalty shrinkage scale max_bal are all functions of the fixed marginal data alone. Caching them once per fit lets every outer REML iterate (50+ per fit on the #1082 tensor cases) skip the repeated eigh() calls and B_k U_k GEMMs; only the cheap kronecker_logdet_and_derivatives λ-grid sweep is redone per iterate.

Fields

marginal_eigenvalues: Arc<Vec<Array1<f64>>>

Marginal eigenvalues from each marginal penalty eigendecomposition.

Arc-shared so handing this structure to the per-iterate memoized engine is an O(1) refcount bump, not a deep array copy.

marginal_qs: Arc<Vec<Array2<f64>>>

Marginal eigenvector matrices U_k.

reparameterized_marginals: Arc<Vec<Array2<f64>>>

Reparameterized marginal designs: B_k · U_k for each marginal k.

max_balanced_eigenvalue: f64

Max balanced-penalty eigenvalue scale max_k-grid Σ_k μ_{k,j_k}/||S_k||_F, used to form the shrinkage ridge floor * max_bal. λ-independent.

Implementations

impl KroneckerInvariantStructure

pub fn compute( marginal_designs: &[Array2<f64>], marginal_penalties: &[Array2<f64>], marginal_dims: &[usize], ) -> Result<Self, BasisError>

Compute the λ-invariant tensor structure once from the fixed marginal data.

Trait Implementations

impl Clone for KroneckerInvariantStructure

fn clone(&self) -> KroneckerInvariantStructure

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for KroneckerInvariantStructure

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

Formats the value using the given formatter.