Re: matsnf segfaults

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

On Thu, 29 May 2003, Alexander Shumakovitch wrote:
> I've just got bitten by a nasty bug in matsnf. If one tries to apply it
> to the matrix attached, one gets:
>   (15:02) gp > m = read("crash_snf");
>   time = 10 ms.
>   (15:02) gp > matsnf(m)
>     ***   bug in GP (Segmentation Fault), please report
>   (15:03) gp >
>
> This happens on 2.4.1, 2.2.5 and CVS versions.

Silly garbage collecting problem [ variable 'mun' was destroyed, then
reused ]

Fixed in CVS (bundled with extensive cleanup), and backported (minimal
patch) to the stable branch.

Thanks !

    Karim.

P.S: Note that the algorithm used is spectacularly inefficient in medium to
large dimensions (it was written to be used for 10 x 10 matrices...), so I
doubt the computation will ever finish.

Done by hand as a sequence of mathnfmod() and transpositions, it requires
less than one minute.
-- 
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://www.parigp-home.de/  [PARI/GP]