Module preprocessing 

Preprocessing for statistical learning — feature scaling and design-matrix prep. Reuses statistics::descriptive. Train/test partitioning lives with the resampling module (it shares the fold/shuffle machinery).

Re-exports

pub use scaling::StandardScaler;

Modules

scaling

Feature scaling — z-score standardization of a row-major feature matrix. Reuses statistics::descriptive for the column mean / std-dev.