-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi,
I've been playing with spaces of modular symbols over finite fields, and I ran into two issues that seem to be separate (they're tickets #1231 and #1232 now): 1. doing ModularSymbols(1,8,0,GF(3)).simple_factors() gives - ------------------------------------------------------------ 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). - ------------------------------------------------------------ The same phenomenon occurs over other finite fields. 2. doing ModularSymbols(1,6,0,GF(2)).simple_factors() gives - --------------------------------------------------------------------------- <type 'exceptions.AssertionError'> Traceback (most recent call last) /home/ghitza/sage/<ipython console> in <module>() /opt/sage/local/lib/python2.5/site-packages/sage/modular/modsym/space.py in simple_factors(self) 996 ASSUMPTION: self is a module over the anemic Hecke algebra. 997 """ - --> 998 return [S for S,_ in self.factorization()] 999 1000 def star_eigenvalues(self): /opt/sage/local/lib/python2.5/site-packages/sage/modular/modsym/ambient.py in factorization(self) 1064 D = sage.structure.all.Factorization(D, cr=True) 1065 assert r == s, "bug in factorization -- self has dimension %s, but sum of dimensions of factors is %s\n%s"%( - -> 1066 r, s, D) 1067 self._factorization = D 1068 return self._factorization <type 'exceptions.AssertionError'>: bug in factorization -- self has dimension 2, but sum of dimensions of factors is 3 (Modular Symbols subspace of dimension 1 of Modular Symbols space of dimension 2 for Gamma_0(1) of weight 6 with sign 0 over Finite Field of size 2) * (Modular Symbols subspace of dimension 1 of Modular Symbols space of dimension 2 for Gamma_0(1) of weight 6 with sign 0 over Finite Field of size 2) * (Modular Symbols subspace of dimension 1 of Modular Symbols space of dimension 2 for Gamma_0(1) of weight 6 with sign 0 over Finite Field of size 2) - ------------------------------------------------------------------------- I have not looked at the implementation, but as far as I know the algorithms with modular symbols work directly over the field of definition, so it seems unlikely that this is related to the problem that Ifti raised a few days ago, about reduction of coefficients modulo prime ideals. Best, Alex -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFHQ6xYdZTaNFFPILgRAgzMAJ9UhL4+sB/aX4KkTGCMuhKzbpJ1VwCfScqU sbMU91l2mRWyVMLdtYEu4vM= =7Moa -----END PGP SIGNATURE----- --~--~---------~--~----~------------~-------~--~----~ 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://sage.math.washington.edu/sage/ and http://sage.scipy.org/sage/ -~----------~----~----~----~------~----~------~--~---