Struct CscMatrix 

pub struct CscMatrix<T: Scalar> { /* private fields */ }

Compressed Sparse Column matrix.

Efficient for:

• Column slicing
• Matrix-vector products with transpose (y = A^T * x)
• Column-wise traversal
• Direct solvers (LU, Cholesky)

Implementations

impl<T: Scalar + Clone> CscMatrix<T>

pub fn new( nrows: usize, ncols: usize, col_ptrs: Vec<usize>, row_indices: Vec<usize>, values: Vec<T>, ) -> Result<Self, CscError>

Creates a new CSC matrix from raw components.

Arguments

• nrows - Number of rows
• ncols - Number of columns
• col_ptrs - Column pointers (length ncols + 1)
• row_indices - Row indices for each non-zero
• values - Non-zero values

Errors

Returns an error if the input is invalid.

pub unsafe fn new_unchecked( nrows: usize, ncols: usize, col_ptrs: Vec<usize>, row_indices: Vec<usize>, values: Vec<T>, ) -> Self

Creates a CSC matrix without validation (unsafe but faster).

Safety

The caller must ensure:

• col_ptrs.len() == ncols + 1
• values.len() == row_indices.len()
• col_ptrs is monotonically increasing
• All row indices are < nrows

pub fn zeros(nrows: usize, ncols: usize) -> Self

Creates an empty CSC matrix with given dimensions.

pub fn eye(n: usize) -> Self

where T: Field,

Creates an identity matrix in CSC format.

pub fn nrows(&self) -> usize

Returns the number of rows.

pub fn ncols(&self) -> usize

Returns the number of columns.

pub fn shape(&self) -> (usize, usize)

Returns the shape (nrows, ncols).

pub fn nnz(&self) -> usize

Returns the number of non-zero elements.

pub fn density(&self) -> f64

Returns the density (nnz / total_elements).

pub fn col_ptrs(&self) -> &[usize]

Returns a reference to the column pointers.

pub fn row_indices(&self) -> &[usize]

Returns a reference to the row indices.

pub fn values(&self) -> &[T]

Returns a reference to the values.

pub fn values_mut(&mut self) -> &mut [T]

Returns a mutable reference to the values.

pub fn get(&self, row: usize, col: usize) -> Option<&T>

Gets the value at (row, col), returning None if not present.

pub fn get_or_zero(&self, row: usize, col: usize) -> T

where T: Field,

Gets the value at (row, col), returning zero if not present.

pub fn col_iter(&self, col: usize) -> impl Iterator<Item = (usize, &T)>

Returns an iterator over the non-zeros in a column.

pub fn iter(&self) -> impl Iterator<Item = (usize, usize, &T)>

Returns an iterator over all non-zeros as (row, col, value).

pub fn to_csr(&self) -> CsrMatrix<T>

Converts to CSR format.

pub fn to_dense(&self) -> Mat<T>

where T: Field + Zeroable,

Converts to dense matrix.

pub fn from_dense(dense: &MatRef<'_, T>) -> Self

where T: Field,

Creates a CSC matrix from a dense matrix.

pub fn transpose(&self) -> Self

Returns the transpose of this matrix.

pub fn scale(&mut self, alpha: T)

Scales all values by a scalar.

pub fn scaled(&self, alpha: T) -> Self

Returns a scaled copy of this matrix.

pub fn col_nnz(&self, col: usize) -> usize

Returns the number of non-zeros in a column.

pub fn is_structurally_symmetric(&self) -> bool

Checks if the matrix is structurally symmetric.

Returns true if A[i,j] != 0 implies A[j,i] != 0.

Trait Implementations

impl<T: Clone + Scalar> Clone for CscMatrix<T>

fn clone(&self) -> CscMatrix<T>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Debug + Scalar> Debug for CscMatrix<T>

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

Formats the value using the given formatter.

impl<T> Index<(usize, usize)> for CscMatrix<T>

where T: Field + Scalar + Clone,

type Output = T

The returned type after indexing.

fn index(&self, (row, col): (usize, usize)) -> &Self::Output

Performs the indexing (container[index]) operation.