pub fn select_pivot(ws: &mut Workspace) -> Option<usize>Expand description
Scan head from ws.mindeg upward and return the first
non-empty degree-list head. Unlink the chosen variable. Returns
None if no bucket in [ws.mindeg, ws.n) is non-empty (i.e.
all remaining supervariables have been dense-deferred and the
main loop should stop).
Side effects: ws.mindeg advances to the degree of the chosen
pivot. head[deg] is advanced to the next element. last[next]
is cleared if a successor exists.
Reference: faer amd.rs:220-235.