On Tue, Nov 25, 2008 at 3:13 PM, William Stein <[EMAIL PROTECTED]> wrote: > > On Tue, Nov 25, 2008 at 3:15 AM, Ondrej Certik <[EMAIL PROTECTED]> wrote: >> >>> One of the issues right now is that sage's piecewise is a completely >>> separate class then the rest of the calculus library. I think it > > Just for the record, this is because Piecewise was implemented long > long ago by David Joyner, probably a year before any of the rest of > the calculus library was implemented. It definitely needs to be > somehow integrated better with the > calculus code as explained here.
I'll try working on this some over the winter break, ie, in 2-3 weeks. > >>> should descend from symbolic expression and be on the same level as, >>> e.g. sin and addition (and probably even have a pynac counterpart). >>> Letting the operands be the conditions (as symbolic equations, giving >>> much more flexibility then we now have) and the corresponding >>> expressions (as symbolic equations) would allow it to fit into the >>> symbolic ring nicely. This would have the advantage that one could >>> leverage all the generic SR functionality like subs, pow, >>> composition, etc. without having to re-implement it for every method >>> that's missing. >> >> Exactly. In fact, that is how Piecewise works in sympy. So I think >> pynac has to know how to properly dispatch stuff like .subs(), >> .series() and other things into the Piecewise class (after it is >> integrated into the calculus). And I know it is possible to do that >> with Cython. Btw, how about pattern matching? Will you extend the C++ >> code in ginac to handle Piecewise functions? >> >> The other option is to reimplement the .subs(), .series() and pattern >> matching in Python. Burcin, please don't take my comments as sarcastic >> --- I am really interested how to handle this and how to cooperate as >> much as possible. Also, how will you approach to fix the bug in pynac >> series I reported here: >> >> http://groups.google.com/group/sage-devel/msg/a59f3c5d0586766b >> >> E.g. will you fix ginac, or rather reimplement it in Cython/Python? >> You can actually still use Maxima for that, so that's not a problem in >> fact. And later just reimplement it in Python/Cython. >> >> Ondrej >> >> > >> > > > > -- > William Stein > Associate Professor of Mathematics > University of Washington > http://wstein.org > > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@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-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
