On Monday 15 September 2008, phil wrote: > I've been pushing the limits of determinant calculation over > multivariate polynomial rings. I can calculate determinants of > matrices up to 9x9 of the form [[x_0_0, x_0_1],[x_1_0, x_1_1]] (each > element is a single unique variable). When I get to 10x10 is runs for > a while the crashes with: > Unhandled SIGSEGV: A segmentation fault occured in SAGE. > This probably occured because a *compiled* component > of SAGE has a bug in it (typically accessing invalid memory) > or is not properly wrapped with _sig_on, _sig_off. > You might want to run SAGE under gdb with 'sage -gdb' to debug this. > SAGE will now terminate (sorry).
I'll try to reproduce the crash and see what I can do about it. You could help by running sage -gdb (if you have gdb installed) and send me the backtrace off list. Thanks. > 9x9 matrices only take about 40 seconds. The 10x10 calculation runs > for a long time (>1 hr) before crashing. This is on 64 bit Ubuntu > with the patch in Trac #4068 (http://trac.sagemath.org/sage_trac/ > ticket/4068) applied. > BTW, what is the underlying algorithm used for the determinants? As > I understand it, the naive way is O(N!) while the recursive way is > O(N^3) for a NxN matrix. See: http://groups.google.com/group/sage-devel/browse_thread/thread/7aa1bd1e945ff372/ Cheers, Martin -- name: Martin Albrecht _pgp: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x8EF0DC99 _www: http://www.informatik.uni-bremen.de/~malb _jab: [EMAIL PROTECTED] --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
