| Karim Belabas on Sun, 07 Dec 2008 19:42:44 +0100 |
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| Re: idealstar |
* Bill Allombert [2008-12-03 04:48]:
> On Tue, Dec 02, 2008 at 06:33:17PM +0100, Karim Belabas wrote:
> > I'd have a look at "ideallog" ...
> >
> > As you mentionned, the bottleneck is the computation of discrete logs in
> > (Z_K / P) for maximal ideals P dividing I. This will be slow if Norm P - 1
> > is not smooth ( basic Pohlig-Hellman + Shanks ).
>
> Well, a basic index calculus implementation for znlog would beat
> the current znlog, use less memory and be easy to implement
> (as long as we do not implement sieving/Lanczos/etc.).
>
> Is it worth the trouble ?
I think so. It's a reasonably basic number theoretic algorithm that
would benefit a lot of PARI functions (in a range where they are
currently not usually applied, granted).
I would gratefully include a reasonable implementation.
Cheers,
K.B.
--
Karim Belabas, IMB (UMR 5251) Tel: (+33) (0)5 40 00 26 17
Universite Bordeaux 1 Fax: (+33) (0)5 40 00 69 50
351, cours de la Liberation http://www.math.u-bordeaux.fr/~belabas/
F-33405 Talence (France) http://pari.math.u-bordeaux.fr/ [PARI/GP]
`