Re: New GP functions for modular polynomials

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

On Fri, Nov 28, 2014 at 03:09:07PM +0100, Andreas Enge wrote:
> On Mon, Nov 17, 2014 at 05:24:03PM +0100, Bill Allombert wrote:
> > We have recently added three new GP functions in PARI GIT 2.8, implemented
> > by Hamish Ivey-Law, using Sutherland algorithm:
> 
> These are very good news indeed!
> 
> > polmodular(l): return the canonical modular polynomial of level l prime.
> > (unfortunately limited to l<=31 in 32bit)
> 
> Actually, in Magma terms, these are the "classical" ones, the canonical
> ones are for the simple eta quotients (I also mix them up all the time...).

Ah sorry, I meant the classical one, yes.

> Following Karim's latest git commit, I noticed that the library function
> is called polmodular, with additional specially typed functions
> modpoly_ZXX etc.; should these not also be renamed polmodular_ZXX etc.?

Maybe, we will do it later.

> > polclass(D): return the Hilbert class polynomial for the imaginary order.
> 
> How about allowing here as an optional parameter a prime p modulo which
> the polynomial is reduced? Then internally a special kind of CRT could be
> used.

This is not implemented yet.

Cheers,
Bill.