Function column_counts_ata 

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

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 $A A^\top$
• post has length A.ncols(): postordering of etree

warning

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