On Mon, Sep 15, 2014 at 12:48 AM, Jeroen Demeyer <[email protected]> wrote: > Hello, > > I would like some opinions about ticket #16931. This ticket is about using > PARI for point counting on elliptic curves over F_q (it's only recently that > PARI supports this, earlier versions only did prime fields F_p). > > The main algorithm PARI uses is SEA, which breaks down if the characteristic > is too small compared to the size of the field. I posted a bug report about > this: http://pari.math.u-bordeaux.fr/cgi-bin/bugreport.cgi?bug=1606 > > This issue has been "fixed" upstream by implementing Kedlaya. However > upstream considers this a change which is "too complex" to go into a > PARI-2.7.x release. So it will be a while before this fix goes into a stable > release. > > I see three possible options (in decreasing order of preference for me): > (1) Upgrade PARI to latest master instead of a stable version. > (2) Backport the Kedlaya implementation to PARI-2.7.x and put that in Sage. > (3) Keep the current slow Sage algorithm for point counting over F_q in the > cases where PARI SEA doesn't work.
(3) clearly seems the safest assuming it is obvious what the cutoff is. (1) is very hard to evaluate -- will it cause all kinds of extra headaches or be easy? This depends immensely on the state of pari development. (2) is also very hard to evaluate -- is it a single function to copy from one c file to another, or are there changes all over? Whether 2 is the best choice depends on information you haven't provided... William > > > Any opinions? > Jeroen. > > -- > You received this message because you are subscribed to the Google Groups > "sage-nt" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send an email to [email protected]. > Visit this group at http://groups.google.com/group/sage-nt. > For more options, visit https://groups.google.com/d/optout. -- William Stein Professor of Mathematics University of Washington http://wstein.org [email protected] -- You received this message because you are subscribed to the Google Groups "sage-nt" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. Visit this group at http://groups.google.com/group/sage-nt. For more options, visit https://groups.google.com/d/optout.
