I have posted a patch for this on trac #2849. The bug would strike for any curve with j=0 (=1728) defined over GF(3^d) for odd d.
Assuming someone reviews this positively it will get into sage-3.0. It is also likely that by then there will be much better support for the cases j=0 and j=1728 anyway. John Cremona On 07/04/2008, William Stein <[EMAIL PROTECTED]> wrote: > > An elliptic curve bug report from a student of Koblitz... > > > ---------- Forwarded message ---------- > From: <[EMAIL PROTECTED]> > Date: Mon, Apr 7, 2008 at 12:39 PM > Subject: elliptic curve trace problem in SAGE > To: [EMAIL PROTECTED] > > > William, > While working on some things, I found a bug in SAGE: > > sage:k.<a>=GF(3^5) > > sage:E=EllipticCurve(k,[-1,-1]) > > sage:E.trace_of_frobenius() > 0 > > This isn't correct. It should be -27. I also discovered you can get > around it. > > sage:E.cardinality_exhaustive() > 271 > > sage:E.trace_of_frobenius() > -27 > > Somehow, doing .cardinality_exhaustive() fixes the bug. > > > > Dustin Moody > > > > > > > > -- > 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 -~----------~----~----~----~------~----~------~--~---
