* Igor Schein [2014-02-06 19:03]:

> On Wed, Feb 5, 2014 at 5:54 AM, Bill Allombert <
> Bill.Allombert@math.u-bordeaux1.fr> wrote:
>
> > On Tue, Jan 28, 2014 at 01:47:20PM -0500, Igor Schein wrote:
> > > Package: pari
> > > Version: 2.6.2 (development 16105-120d04c)
> > >
> > > The following command never finishes:
> > >
> > >
> > nfsubfields(x^32-152*x^30+9592*x^28-329344*x^26+6791636*x^24-87823728*x^22+723817584*x^20-3802250784*x^18+12604302140*x^16-26054878368*x^14+33346127520*x^12-26066364480*x^10+12062323568*x^8-3111766784*x^6+403544704*x^4-21688960*x^2+364816);
> >
> > Hello Igor,
> > As far as I see, the command will finish eventually.
> > However it will be very slow, because we are unlucky: the d-1 test is
> > failing for
> > all tests, and nfsubfields does not have a fast fallback code like
> > nfgaloisconj
> > does.
> >
> > Cheers,
> > Bill.
> >
>
> Thanks.  Can nfsubfields() be improved in cases like this?

Yes, the Klueners / van Hoeij algorithm is easy to implement. Will work
on this once 2.7 is out.

> It'd be nice to have a mechanism (similar to ulimit in bash) to impose
> runtime limit on individual function calls - it would also be an adequate
> solution for me.  I've had this on my mind for at least 15 years, but I
> don't recall if I ever brought it up.

?? alarm

:-)

Cheers,

    K.B.

`