ifoldl (f col_idx) (q,r) col
-- | Process the entries in a column, doing basically the same
- -- thing as col_dunction does. It updates the QR factorization,
+ -- thing as col_function does. It updates the QR factorization,
-- maybe, and returns the current one.
f col_idx (q,r) idx _ -- ignore the current element
| idx <= col_idx = (q,r) -- leave it alone