On Sun, 22 Feb 2015 03:17:13 -0800 (PST) Volker Braun <vbraun.n...@gmail.com> wrote:
> Just to tell you what you already know, the symbolic ring is the > parent of last resort if there is nothing more specific. So its to be > expected that you don't have any canonical maps elsewhere. > > Pynac should probably unwind the comparison of two wrapped > (non-symbolic) python objects to the comparison of the underlying > python objects. Haven't tried that, though. You have to be careful > about infinite recursions, the comparison might again coerce into the > symbolic ring. Pynac already calls the Python comparison function if both are pyobjects. In this case, infinity and constants are not pyobjects. They are a basic class as in mul, add, symbol, etc. Cheers, Burcin P.S. The infinity class was added to pynac by Volker. :) > On Sunday, February 22, 2015 at 11:02:44 AM UTC+1, Ralf Stephan wrote: > > > > Hello, > > a long standing issue is > > > > sage: bool(pi<Infinity) > > False > > sage: bool(SR(3)<Infinity) > > False > > > > http://trac.sagemath.org/ticket/12967 > > at which I'm having a naive stab (because it interferes with > > #14801). Maybe I can learn something? > > > > In the ticket the problem has been said having to do with Pynac, > > but I don't think so. It would all work nicely if, instead of the > > expression > > object, its underlying `pyobject` would be compared. But this does > > not happen because there is no coerce map from `SR` to > > `InfinityRing`. > > > > So, can we somehow have an indirect coercion map that uses not > > the parent but the parent of something a member function (like > > `pyobject`) returns? The problem of SR having no canonical map to > > anything in spite of some expressions being well behaved is the > > source of much frustration. > > > > Regards, > > -- 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 http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
