//! Matrix decompositions, one per file — general-purpose kernels for
//! future use across the library (regression, calibration, PCA, factor
//! models), independent of any finance semantics.
//!
//! - [`cholesky`]: `A = L L^T` for symmetric PSD matrices, plus the SPD
//! linear solve through the factor — the fast path for normal
//! equations and covariance sampling;
//! - [`qr`]: Householder QR (`A = Q R`, thin form), plus numerically
//! stable linear least squares — the right tool for regression
//! (e.g. Longstaff-Schwartz bases) without forming `A^T A`;
//! - [`svd`]: one-sided Jacobi singular value decomposition
//! (`A = U S V^T`), plus the minimum-norm pseudo-inverse solve for
//! rank-deficient problems;
//! - [`eigen`]: cyclic Jacobi eigendecomposition of symmetric matrices —
//! the engine behind the PSD projection in
//! [`nearest_correlation`](super::nearest_correlation).
//!
//! All matrices are `Vec<Vec<f64>>` row-major, matching the rest of the
//! crate; the implementations favor clarity and robustness on the
//! small-to-moderate sizes quant workflows use.
pub use ;
pub use symmetric_eigen;
pub use ;
pub use ;