I must admit that I do not know what that method call exactly does, but calling it resolve the mentionned bug. Moreover it is called in different places all over the file in a similar manner so I have the feeling that it could be an acceptable fix. I'll open a trac ticket with that fix and a doctest hoping that someone with a better understanding of ntl and gf2x will confirm that it is ok or provide a correct fix.
Cheers, On 27 mai, 15:22, Jean-Pierre Flori <jpfl...@gmail.com> wrote: > Adding > > (<FiniteField_ntl_gf2e>self._parent).F.restore() > before calling > cdef GF2X_c r = GF2X_IrredPolyMod(GF2E_rep(self.x),GF2E_modulus()) > fixes everything. > Not sure yet why it does not get called before in that situation... > > On 27 mai, 15:03, Jean-Pierre Flori <jpfl...@gmail.com> wrote: > > > > > > > > > Putting sig_on/sig_off around: > > sig_on() > > cdef GF2X_c r = GF2X_IrredPolyMod(GF2E_rep(self.x), > > GF2E_modulus()) > > sig_off() > > I get: > > /home/jp/boulot/sage/sage-4.7.rc1/local/lib/python2.6/site-packages/ > > sage/rings/finite_rings/element_ntl_gf2e.so in > > sage.rings.finite_rings.element_ntl_gf2e.FiniteField_ntl_gf2eElement.minpoly > > (sage/rings/finite_rings/element_ntl_gf2e.cpp:11156)() > > > RuntimeError: build GF2XArgument: bad args > > > What is also strange is that it only happens for the second element... > > > On 27 mai, 14:49, Simon King <simon.k...@uni-jena.de> wrote: > > > > Hi Jean-Pierre, > > > > On 27 Mai, 14:31, Jean-Pierre Flori <jpfl...@gmail.com> wrote: > > > > > I'll take care of it with a fix hopefully. > > > > It turns out that the error occurs in the list() method of a homset, > > > which starts with > > > > sage: K = GF(1<<16,'a'); L = GF(1<<32,'b') > > > sage: self = K.Hom(L) > > > sage: D = self.domain() > > > sage: C = self.codomain() > > > sage: f = D.modulus() > > > sage: g = C['x'](f) > > > sage: r = g.roots() > > > > Now, the following works: > > > sage: for a,_ in r: > > > ....: print a > > > ....: t = D.hom(a,C) > > > ....: > > > > But this segfaults!! > > > sage: for a,_ in r: > > > ....: t = D.hom(a,C) > > > ....: > > > > In other words, printing the elements `a` seems to initialise some > > > data, and without printing them data are missing, resulting in a > > > segfault. Or put differently, the initialisation of finite field > > > elements is incomplete. > > > > By the way, the elements `a` have a custom __repr__ method - shouldn't > > > it be _repr_ with a single underscore? > > > > Cheers, > > > Simon -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
