Hi Greg, On Mon, 22 Mar 2010 15:47:54 -0700 (PDT) G B <g.c.b.at.w...@gmail.com> wrote:
> Burcin-- > > Now that I've managed to divide the discussion between two groups, I > should try to help organize the mess I made. > > Ondrej mentioned in the sage-support discussion that he's opened > ticket 8564. Unfortunately I don't understand the plumbing well > enough to know if 8564 and 8565 are addressing the same or different > problems. As you mention, Sage seems to import atan2 from GiNaC. > 8564 looks to be improving the import of the functionality from Sympy. They are unrelated issues. > From a user perspective, it would be best if the default flavor worked > without needing to learn the unique syntax of a sub-package, but > beggars can't be choosers. =) Yep, we really need to fix the atan2 in Sage. > I'm happy to try and help if given some guidance. I'm a reasonably > capable programmer, but I'm completely unfamiliar with Sage and a > touch intimidated by the complexity of it. I can help with the first steps. Although the fix doesn't seem so obvious to me (I don't have time to start debugging properly), it should still be a good project to start with. The code for evaluating atan2 lives in the c++ library pynac [1], which is based on GiNaC. [1] http://pynac.sagemath.org/ There are two approaches to fix this problem, - one can either look into the "automatic evaluation" [2, 3] function of atan2 in GiNaC [4], [2] http://www.ginac.de/tutorial/Symbolic-functions.html [3] http://www.ginac.de/tutorial/Automatic-evaluation.html [4] http://pynac.sagemath.org/hg/file/9ff767fb0c18/ginac/inifcns_trans.cpp#l971 You can also just report the problem to the GiNaC developers by writing to the ginac-list mailing list: http://www.ginac.de/Lists.html - or override the automatic evaluation function with a python function (I implemented this recently in pynac.) by defining an _eval_() method in the class sage.functions.trig.Function_arctan2. If you choose to fix the c++ code here is a short guide to get started with pynac development: http://wiki.sagemath.org/pynac/start Feel free to ask more questions. Especially the symbolics subsystem and the pynac interface really needs documentation. I find that answering questions is way easier than writing manuals. Thank you. Burcin -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org To unsubscribe from this group, send email to sage-devel+unsubscribegooglegroups.com or reply to this email with the words "REMOVE ME" as the subject.
