hey, factoring-testing guys.. If you make up factoring problems this way, you are probably not doing much testing of the real factoring algorithms. Repeated factors like this of different degree are detected by so-called square-free factorization. The time to factor F in Maxima is, to the resolution of the clock, 0.0000 seconds on a 3GHz Intel machine.
F can also be entirely factored by the sqfr program, which uses a 5 line program involving differentiation, GCD, and division. So the problem is essentially no harder than factoring f and g separately. There are papers that show how to construct polynomials that are difficult to factor. I dunno about the Sage wrapper problem. If that's the difficulty, maybe the subject line is wrong. RJF On Oct 1, 1:21 am, Andy Novocin <a...@novocin.com> wrote: > By the way, last October I made a patch for NTL which makes NTL's > factoring significantly faster than even MAGMA's in some cases. I > think that the degree flags < 30 and > 300 for NTL's factoring > (provided my patch went in) needs to be revisited anyway. > > On Oct 1, 8:37 am, Robert Bradshaw <rober...@math.washington.edu> > wrote: > > > On Sep 30, 2009, at 8:25 PM, William Stein wrote: > > > > On Wed, Sep 30, 2009 at 7:13 PM, Marshall Hampton > > > <hampto...@gmail.com> wrote: > > > >> Wow, that's quite disturbing. Did you make a trac ticket for this? > > > > I've made this: > > > >http://trac.sagemath.org/sage_trac/ticket/7088 > > > > and made it a 4.1.2 blocker, since it a serious bug. The problem is > > > in the _factor_pari method in Sage. It's almost certainly a bug in > > > Sage's wrapper of Pari for factoring in the non-monic case. The > > > solution will be either to fix that (good) or use the ntl wrapper > > > (wimpy). > > > Wow, it looks like this bug has been around since the very first > > checkin. I posted a patch. > > > - Robert > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
