Module regression 

Regression functions for functional data.

This module provides functional PCA, PLS, and ridge regression.

Canonical result-field vocabulary (API-01)

FpcaResult defines the canonical vocabulary reused across the crate’s FPCA-based result structs:

Field	Meaning
scores	FPC scores, n × ncomp (observations projected onto the component basis)
rotation	Loadings / eigenfunctions, m × ncomp (the component basis)
mean	Estimated mean function, length m
weights	Integration weights for the functional inner product, length m
singular_values	Singular values of the centered data (component scale)
centered	The mean-centered data, n × m

Response-carrying result structs (e.g. crate::fts::FtsmResult, crate::boosting_regression::BoostFosrResult, and the FOSR result types) expose the fitted response under the field name fitted; this is the accepted canonical name for a fitted-response field across the crate (the historical fitted_values spelling is not introduced). No field is renamed here — the cross-model unification layer is provided by the crate::explain_generic::FpcPredictor trait, which abstracts over the concrete result structs so callers need not depend on any single struct’s field names. Any future field rename would be a breaking change and is deferred to the 1.0-readiness milestone (APIB-01).

Structs

FpcaResult

Result of functional PCA.

PlsResult

Result of PLS regression.

Functions

fdata_to_pc_1d

Perform functional PCA via SVD on centered data with integration weights.

fdata_to_pls_1d

Perform PLS via NIPALS algorithm with integration weights.