I haven't tried QPA but it seems to be a pure GAP script, so I would expect that performance will be comparable to a pure Python implementation. But it looks like a very nice project and its likely that it would be of some use even if the core computations of a Sage quiver module were implemented differently.
A C++/Cython implementation of the basic path algebra arithmetic with bit-packed exponents and arbitrary coefficient rings would be a nice thing to have though ;-) On Wednesday, November 21, 2012 11:45:39 AM UTC, Simon King wrote: > > Hi Combinat folks! > > I see on the Sage Combinat Road Map on trac that there are some tickets > dedicated to path algebras: #9889, #12630 and something which appears to > have no ticket yet, namely an interface to QPA in Gap. > > What I'd need is: Path algebras over an arbitrary finite quiver > (loops will occur) with coefficients in a finite field (non-prime fields > will occur). The path algebras will be equipped with a monomial ordering > ("monomials" corresponding to paths). And of course the implementation > should be very efficient in basic arithmetics, in comparison of monomials, > and in using monomials as cache keys. > > - Am I right that those things are currently unavailable in Sage? > - Am I right that #12630 would not help me, since it is restricted to > the loop-less case? > - Am I right that #9889 would not help me, since it is pure Python and > thus not very efficient, and does not provide monomial orderings? > - I had a look at the QPA package - it looks like it would do the right > things for me (there is even talk about Gröbner bases and Ext > algebras, which is totally in my scope), but the package is not in the > list of "accepted packages" and not even in the list of "deposited > packages" of GAP. Do you know whether the implementation is > competitive? Is there a ticket to make it available in Sage? > > So, what do you recommend to do? Try to use QPA in Sage via the new > libGAP (I guess the GAP pexpect interface would be too slow)? Or try and > write my own implementation? > > Cheers, > Simon > > > -- You received this message because you are subscribed to the Google Groups "sage-combinat-devel" group. To view this discussion on the web visit https://groups.google.com/d/msg/sage-combinat-devel/-/ltC_jTAPSuwJ. To post to this group, send email to sage-combinat-devel@googlegroups.com. To unsubscribe from this group, send email to sage-combinat-devel+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sage-combinat-devel?hl=en.