Struct DenseMatrix 

#[non_exhaustive]
pub struct DenseMatrix { /* private fields */ }

A contiguous, column-major dense matrix.

Layout: data[col * n_rows + row].

This replaces Vec<Vec<f64>> for feature storage, providing:

• Zero-cost column slicing via col
• Single contiguous allocation instead of N+1 heap blocks
• Cache-friendly access patterns for column-oriented ML algorithms

Implementations

impl DenseMatrix

pub fn new(data: Vec<f64>, n_rows: usize, n_cols: usize) -> Result<Self>

Create a matrix from a flat column-major buffer.

Returns an error if data.len() != n_rows * n_cols.

pub fn zeros(n_rows: usize, n_cols: usize) -> Self

Create a matrix of all zeros.

pub fn from_col_major(cols: Vec<Vec<f64>>) -> Result<Self>

Build from column-major Vec<Vec<f64>> (each inner vec is one column).

Returns an error if columns have different lengths.

pub fn from_row_major(rows: &[&[f64]], n_rows: usize, n_cols: usize) -> Self

Build from row-major data, transposing into column-major storage.

pub fn col(&self, j: usize) -> &[f64]

Zero-cost slice of column j.

pub fn col_mut(&mut self, j: usize) -> &mut [f64]

Mutable slice of column j.

pub fn get(&self, row: usize, col: usize) -> f64

Get a single element.

pub fn set(&mut self, row: usize, col: usize, val: f64)

Set a single element.

pub fn n_rows(&self) -> usize

Number of rows.

pub fn n_cols(&self) -> usize

Number of columns.

pub fn as_slice(&self) -> &[f64]

The raw flat buffer in column-major order.

pub fn row_iter(&self, i: usize) -> impl Iterator<Item = f64> + '_

Iterate over values in row i (strided access across columns).

pub fn row_to_vec(&self, i: usize) -> Vec<f64>

Collect row i into a Vec<f64>.

pub fn from_col_major_ref(cols: &[Vec<f64>]) -> Result<Self>

Build from a reference to column-major &[Vec<f64>] (no ownership transfer).

Same as from_col_major but borrows the columns instead of consuming them, avoiding a clone of the outer Vec.

pub fn to_col_vecs(&self) -> Vec<Vec<f64>>

Convert back to Vec<Vec<f64>> column-major (backward compat).

Trait Implementations

impl Clone for DenseMatrix

fn clone(&self) -> DenseMatrix

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DenseMatrix

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

Formats the value using the given formatter.

impl From<&[Vec<f64>]> for DenseMatrix

fn from(cols: &[Vec<f64>]) -> Self

Converts to this type from the input type.

impl From<Vec<Vec<f64>>> for DenseMatrix

fn from(cols: Vec<Vec<f64>>) -> Self

Convert from column-major Vec<Vec<f64>>. Panics on ragged input.