On Tue, Aug 26, 2008 at 1:19 AM, Ondrej Certik <[EMAIL PROTECTED]> wrote: > > On Tue, Aug 26, 2008 at 10:16 AM, Burcin Erocal <[EMAIL PROTECTED]> wrote: >> >> On Tue, 26 Aug 2008 00:40:22 -0700 (PDT) >> Michel <[EMAIL PROTECTED]> wrote: >> >>> >>> An assumption framework is non-trivial as it is basically >>> computational >>> real algebraic geometry. >>> >>> Recenty there was a post about QEPCAD (http://www.cs.usna.edu/~qepcad/ >>> B/QEPCAD.html). >>> Perhaps this might fit the bill? >> >> AFAIK, MMA indeed uses cylindrical algebraic decomposition (CAD) for >> this, and it would be great to have an efficient CAD implementation in >> Sage. I am not an expert on this issue, but from what I have heard, >> qepcad has its advantages (more flexible?) and disadvantages (slow?) >> compared to the CAD implementation in MMA. >> >> qepcad relies on an aging library saclib for the algebraic data >> structures. It would be a worthwhile project to implement CAD/port >> qepcad so that it is modular, and can work with more recent/better >> libraries. Maybe someone (Carl Witty?) will take this on (or already >> has?). :)
I think Carl Witty has done a bunch. He gave a talk about this at Sage Days 8.5. Maybe he'll comment on this thread. > Yes, but this is not necessary to get the infrustructure in and get > the easy cases working and working fast. > > qepcad or other things will come handy when doing the general cases, > where simple heuristics will fail. E.g. it's like with limits, the > gruntz algorithm is nice and working, but all easy cases can be done > (and are done) with heuristics, because it is simpler and way faster. Interesting. -- William --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
