I have opened https://trac.sagemath.org/ticket/28042 This looks pretty bad...
On Fri, Jun 21, 2019 at 4:20 PM Clement Pernet <clement.per...@gmail.com> wrote: > > Hi, > > The following simple session triggers what I think is at least one bug, if > not two: > > sage: p=193379 > sage: K=GF(p) > sage: a=K(1) > sage: b=K(191495) > sage: c=K(109320) > sage: d=K(167667) > sage: e=103937 > sage: a*c+b*d-e > 102041 > sage: vector([a,b])*vector([c,d])-e > -91339 > sage: -91339+e > 12598 > sage: vector([a,b])*vector([c,d]) > 12599 > > > Namely, the scalar product of GF(p) elements followed by a subtraction is > negative (first bug). > > Then the negative value is off by one (second bug). > > Some weird coercion seem to happen between IntegerMod_int64 IntegerMod_int > and ZZ: > > sage: type(vector([a,b])[0]) > <type 'sage.rings.finite_rings.integer_mod.IntegerMod_int64'> > sage: type(vector([a,b])*vector([c,d])) > <type 'sage.rings.finite_rings.integer_mod.IntegerMod_int'> > > Are these known bugs? > > Best. > > Clément > > -- > You received this message because you are subscribed to the Google Groups > "sage-devel" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sage-devel+unsubscr...@googlegroups.com. > To post to this group, send email to sage-devel@googlegroups.com. > Visit this group at https://groups.google.com/group/sage-devel. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sage-devel/efa76bd3-53ba-e1af-5e84-b3ea428836de%40gmail.com. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/CAAWYfq1VLLizWoHb2dafuO_T4OK1kjDkGgyFELdP_0%2BP0TUhKA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
