Function extendr_api::prelude::sparse::linalg::qr::column_counts_ata

pub fn column_counts_ata<'m, 'n, I>(
    col_counts: &mut [I],
    min_col: &mut [I],
    AT: SymbolicSparseColMatRef<'_, I>,
    col_perm: Option<PermRef<'_, I>>,
    etree: EliminationTreeRef<'_, I>,
    post: &[I],
    stack: PodStack<'_>,
)
where
    I: Index,

Computes the column counts of the Cholesky factor of $A\top A$.

• col_counts has length A.ncols().
• min_col has length A.nrows().
• col_perm has length A.ncols(): fill reducing permutation.
• etree has length A.ncols(): column elimination tree of $A A^H$.
• post has length A.ncols(): postordering of etree.

Warning

The function takes as input A.transpose(), not A.