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,
Expand description
Computes the column counts of the Cholesky factor of $A\top A$.
col_counts
has lengthA.ncols()
.min_col
has lengthA.nrows()
.col_perm
has lengthA.ncols()
: fill reducing permutation.etree
has lengthA.ncols()
: column elimination tree of $A A^H$.post
has lengthA.ncols()
: postordering ofetree
.
ยงWarning
The function takes as input A.transpose()
, not A
.