Re: ellgenerators

[Max Alekseyev <maxale@gmail.com>]

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?
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. ÂIt's fairly easy to issue a system call to
> ratpoints from gp in order to get an list of rational points. ÂFrom there,
> it's just a few more lines of gp script to extract the generators and
> determine a lower bound for rank. ÂThe 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]))
>> Â*** Â at top-level: ellgenerators(ellini
>> Â*** Â Â Â Â Â Â Â Â ^--------------------
>> Â*** ellgenerators: error opening elldata file:
>> `/usr/local/share/pari/elldata/ell1816'.
>> Â*** Â Break loop: type 'break' to go back to GP
>>
>> sage: EllipticCurve([-35750837071872,63237970697887678464]).gens()
>> [(-2365632 : 11600547840 : 1)]
>>
>> Thanks,
>> Max
>
>