In 3.3 and 3.4.rc0, I get a segmentation fault when I try and compare certain elements of congruence subgroups.
sage: r,s,t,u = Gamma0(2).gens() sage: r**(-1)*u**(-1) [-1 -1] [ 2 1] sage: t [-1 -1] [ 2 1] These look pretty equal, don't they? That's not a problem in itself, as gens() isn't supposed to return a minimal set of generators. The problem is that sage: t == r**(-1)*u**(-1) False and worse still sage: r**(-1)*u**(-1) == t Unhandled SIGSEGV: A segmentation fault occured in SAGE. Any suggestions on why this is happening? I can't replicate the failure on earlier versions as the output of Gamma0(2).gens() isn't the same. If I manually create CongruenceSubgroupElement objects with the same entries and parent as r,s,t,u, then it all works fine, so somehow the gens method -- which is a wrapper around the Cython code in congroup_pyx.generators_helper -- must be returning objects that are "broken" in some way. David --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
