On 2013-01-24, Jeroen Demeyer <[email protected]> wrote: > While testing for speed regressions due to #12313, I actually > encountered a serious slowdown from sage-5.5 to sage-5.6: > > def test(): > for count in range(12): > for n in [2..20]: > for g in Gamma0(n).gamma_h_subgroups(): > G = g.image_mod_n() > assert G.order() == Gamma(n).index() / g.index() > > time test() >
If I read what Volker noticed right, in this code the bulk of time is spent computing the order of a group of 2x2 matrices by converting it into a permutation group, via GAP. And the order of the group is never more than 342 here. A naive algorithm, enumerating the elements of the matrix group directly, would speed this up hugely, IMHO. Dima -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sage-devel?hl=en.
