Re: yet another rnfkummer() posting

[Igor Schein <igor@txc.com>]

On Sun, Sep 08, 2002 at 10:32:18PM +0200, Karim BELABAS wrote:
> On Wed, 4 Sep 2002, Igor Schein wrote:
> > ? setrand(2);rnfkummer(bnrinit(bnfinit(quadpoly(-6580,y)),9,1),matdiagonal([3,1,1,1]));
> >   ***   not an Abelian extension in rnfnormgroup.
> 
> On Fri, 6 Sep 2002, Igor Schein wrote:
> > ? \p400
> >    realprecision = 404 significant digits (400 digits displayed)
> > ? setrand(3);rnfkummer(bnrinit(bnfinit(quadpoly(2540,y),1),9,1),[3,1;0,1]);
> >   ***   precision too low in isunit.
> >
> > Before it was working fine at default precision.
> 
> Just to recap. These two are the only surviving bugs in the "bnfinit & friends"

I believe I found 1 more, extremely complicated and extremely fatal (
it took me the whole day just to narrow it down): 

? setrand(1);bnf=bnfinit(quadpoly(-7287,y));
? v=subgrouplist(bnrinit(bnf,25,1),5,1);
? rnfkummer(bnrinit(bnf,25,1),v[19]);
? rnfkummer(bnrinit(bnf,25,1),v[20]);
Segmentation fault

And the session crashes ( after less than 2min on a 1.7GHz machine ).

Note that I have to call bnrinit() 3 times, otherwise, I guess, the
random seed changes and the problem is not reproducible anymore.

Also, this appears to be a Linux/i386-specific bug, FreeBSD and
Solaris are not vulnerable ( I haven't tried 64bit ).

Thanks

Igor