On 26/08/2008, at 2:50 AM, William Stein wrote: > Burcin -- I did actually mostly implement pattern matching in Pynac.
Is there documentation? A bit of google turned up nothing. > sage: sin(1+sin(x)).subs(sin(w0)==cos(w0)) > cos(cos(x) + 1) In Mathematica, the result would be cos(sin(x) + 1), since having matched the outer expression, the replacement algorithm moves on rather than in. One would obtain cos(cos(x) + 1) by making the substitution rule sin==cos. Can you do that? Can you evaluate code during the matching of your patterns? Can you nest patterns? I think these are highly desirable, even if they are suitably carefully hidden from the casual user. On 26/08/2008, at 1:24 AM, in a different thread, Burcin Erocal wrote: > We already have a pretty good "symbolic engine" in Sage, maxima does > quite a good job of solving integrals, limits, etc. The main problem > with Maxima is that we cannot extend it. Is "not extending of Maxima" a concrete policy? I understand that maxima sucks in some circumstances, but it seems quite the beast here. I am quite confused about a lot of the pattern matching discussion. AFAICT, that is the problem for which lisp rocks, and the best way to do it is probably to write maxima code for it. And the best way to make it accessible from python is to provide pretty python methods to call lisp. Any other suitably general form of pattern mathematical matching will involve the proverbial reimplementation of lisp. D p.s. this is obviously from my fairly basic "lisp is more or less mathematica" understanding of lisp. ================================== David J Philp Postdoctoral Fellow National Centre for Epidemiology and Population Health Building 62, cnr Mills Rd & Eggleston Rd The Australian National University Canberra ACT 0200 Australia T: +61 2 6125 8260 F: +61 2 6125 0740 M: 0423 535 397 W: http://nceph.anu.edu.au/ CRICOS Provider #00120C --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@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-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
