| John Cremona on Wed, 30 May 2012 14:13:57 +0200 |
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| Re: ellgenerators |
On 30 May 2012 13:11, Max Alekseyev <maxale@gmail.com> wrote: > Kevin, thanks for the idea. > I'm currently making system calls to sage in order to get generators > when pari fails. > Is there any advantage in calling ratpoints instead? ratpoints is Stoll's C/C++ program for point searching, ans is also available from Sage if that helps. It tells you nothing about the rank, or relations between the points found. John (sent to the right address this time I think) > Regards, > Max > > On Wed, May 30, 2012 at 3:32 PM, Kevin Acres > <research@research-systems.com> wrote: >> Hi Max, >> >> I've recently extracted many 10's of millions of MW curves with conductors >> in the region of 10^32. It's fairly easy to issue a system call to >> ratpoints from gp in order to get an list of rational points. From there, >> it's just a few more lines of gp script to extract the generators and >> determine a lower bound for rank. The whole process usually takes just a >> few milliseconds per curve. >> >> Currently I'm processing about 300,000 curves per day in this fashion but >> discarding anything less than rank 8. >> >> If you want some code samples please let me know. >> >> >> Best Regards, >> >> Kevin. >> >> >> >> At 08:35 PM 30/05/2012, Max Alekseyev wrote: >>> >>> Why pari cannot compute generators of an elliptic curve, while sage can? >>> I thought they have roughly the same "power" w.r.t. elliptic curves. >>> >>> ? ellgenerators(ellinit([-35750837071872,63237970697887678464])) >>> *** at top-level: ellgenerators(ellini >>> *** ^-------------------- >>> *** ellgenerators: error opening elldata file: >>> `/usr/local/share/pari/elldata/ell1816'. >>> *** Break loop: type 'break' to go back to GP >>> >>> sage: EllipticCurve([-35750837071872,63237970697887678464]).gens() >>> [(-2365632 : 11600547840 : 1)] >>> >>> Thanks, >>> Max >> >> >