Struct SmoothStructureAnalysis 

pub struct SmoothStructureAnalysis {
    pub ownership_order: Vec<usize>,
    pub term_feature_cols: Vec<Vec<usize>>,
    pub term_owners: Vec<Vec<usize>>,
}

Static (spec-only) description of the hierarchical smooth-ownership decomposition.

This is the single source of truth for the deterministic ownership policy that apply_global_smooth_identifiability uses during the fit: the processing order of smooth terms, the feature columns each term spans, the candidate lower-order owners of each term (nested/duplicate feature sets), and the basis-family rank used as a tie-breaker. The fit engine consumes this structure and additionally applies a numerical cross-residual overlap test on the realized design columns; the CLI structure-warning path consumes the same structure for diagnostic messages, so both paths agree on which smooths own which subspaces.

Fields

ownership_order: Vec<usize>

Smooth-term indices sorted into ownership-processing order (lowest priority first): lower-order / narrower smooths come first and own their subspaces.

term_feature_cols: Vec<Vec<usize>>

term_feature_cols[idx] are the sorted, deduplicated feature columns that smooth term idx spans (indexed by the original smooth-term index, not by ownership_order).

term_owners: Vec<Vec<usize>>

term_owners[idx] are the indices of prior (in ownership_order) smooth terms whose feature set is a subset of term idx’s feature set, i.e. candidate owners of idx. The list is given in ownership-processing order.