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?). :)
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. Ondrej --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
