Re: bnrisprincipal to slow

[Karim BELABAS <Karim.Belabas@math.u-psud.fr>]

On 8 Dec 2003, Markus Endres wrote:
> I want to compute the exponents on the class group generators of a given
> bnr (in bnrinit) with bnrisprincipal.
>
> I know, if I use the flag 0, than I only get the exponents. But for my
> examples this is too slow. One computation with bnrisprincipal is about
> 4 minutes, and I have a lot of these computations (on a fast computer!).
>
> Is there a faster method to compute the exponents on the class group
> generators?

First make absolutely sure you are using the CVS version of PARI [ headers
should read something like

        GP/PARI CALCULATOR Version 2.2.7 (development CHANGES-1.873)

with possibly a slightly lower patchlevel. ]

The development version is orders of magnitude faster than the stable ones
(2.1.*) for algebraic number theory (and a few other things). If you do not
have CVS, you can get a snapshot from

  http://pari.math.u-bordeaux.fr/

( Download section )

If you are already using the development version, can you send me your
example ?

    Karim.
-- 
Karim Belabas                     Tel: (+33) (0)1 69 15 57 48
Dép. de Mathématiques, Bât. 425   Fax: (+33) (0)1 69 15 60 19
Université Paris-Sud              http://www.math.u-psud.fr/~belabas/
F-91405 Orsay (France)            http://pari.math.u-bordeaux.fr/  [PARI/GP]