Bill Allombert on Tue, 08 Sep 2015 19:06:58 +0200

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Re: SEA without seadata

On Mon, Sep 07, 2015 at 03:28:50PM +0200, Bill Allombert wrote:
> Dear PARI developers,
> I have pushed a patch to master which allow ellap/ellcard to use the
> function polmodular written by Hamish instead of (or in addition to) 
> the seadata database for the SEA algorithm.
> This means that you can now:
> 1) use SEA without installing seadata (but this is will be at least three time
> slower)
> 2) use SEA for fields that are so large they exhaust seadata. 

An example:

? p=nextprime(2^1200);E=ellinit([1,5],p);ellap(E)
%5 = -6406302751743670778436449985059273221847339658151681884226689558480131779196962880021436806438460746120382135677025301722355718942715320150690927385821748846184438904805661975226027

(this involves the computation of modular polynomials in gamma_2 up to degree 719,
which using the parallel version is done relatively quickly on multiple cores)