Re: ell from j

[Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>]

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 ?

Cheers,
Bill.