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. >> 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 -~----------~----~----~----~------~----~------~--~---
