[PARI-2.0.x.beta, x>14] Strange behavior of matdet

[Philippe Elbaz-Vincent <pev@pev.math.univ-montp2.fr>]

Dear all,

I have noticed the following (cumbersome) problem with matdet, as the
title
suggests it occurs with all the available versions of PARI-2.0.x, with
x>14.
(see below for the config).

Set 

P=[-290,107,0,0,0,0,0;-2713,1001,0,0,0,0,0;0,0,-3, 2, -5, 1, -1;0,0,-1,
-1, -2, -2, -1;0,0,1 , 1,  3,  10,  2;0,0,33,  0,  1,  32, 5;0,0, 1, 
1,  3,  -1,  1];

then 

(23:41) gp > matdet(P)
%2 = -2051114900000   <--- Wrong answer ....

But

(23:42) gp > matdet(P,1)
%3 = 1

which is the correct answer.

Is it a normal behavior for the Gauss-Bareiss method ??

NB: H. Gangl has pointed out to me that the behavior also occurs for
the Ultrasparc version.

best,Ph.

Config: Linux-2.2.13 on a PII, mainly based on SuSE 6.2, with
glibc-2.1.1.
tests done with different compilers: gcc-2.95.1, egcs-1.1.2 and another 
dev. version of egcs, and with different kind of flags. All versions are
with readline enabled.

-- 
Laboratoire Geometrie-Topologie, Algebre, UPRESA CNRS 5030
http://www.math.univ-montp2.fr/GTA/