Re: ell from j

[John Cremona <john.cremona@gmail.com>]

On 8 June 2012 21:44, Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr> wrote:
> On Fri, Jun 08, 2012 at 09:04:57PM +0100, John Cremona wrote:
>> I wrote a similar function for Sage,  called EllipticCurve_from_j, but
>> it is not normally called directly, rather one does EllipticCurve
>> (j=...).  Can gp use named parameters, so you could do ellinit(j=...)?
>
> No, that would just set j to the value and call ellinit(j).
>
>> The Sage function has special cases for characteristics 2 and 3, and
>> also over Q it gives a minimal quadratic twist.  You are welcome to
>> reuse that code :)
>
> Where is it ?


http://hg.sagemath.org/sage-main/file/9ab4ab6e12d0/sage/schemes/elliptic_curves/constructor.py

from line 374.

John

>
> Cheers,
> Bill.
>