Re: Possible bug in znprimroot

[Max Alekseyev <maxale@gmail.com>]

myroots(p) expects p to be prime, while 1729 is not prime.
That's probably the reason that triggers the bug.
Anyway, Floating Point Exception should not happen under any circumstances.

Regards,
Max


On Wed, Jan 12, 2011 at 1:54 AM, Kevin Acres
<research@research-systems.com> wrote:
> Hi,
>
> Running the following code:
>
> myroots(p) ={
> Â Âlocal(g);
> Â Âg=znprimroot(p^2)^p;
> Â Â/*vecsort*/(vector(p-1,i,lift(g^i)));
> }
> {
>
> Â Âv=myroots(1729);
> Â Âprint([#v,v]);
> }
>
> Gives the following message:
>
>
> Â Â Â Â GP/PARI CALCULATOR Version 2.4.2 (development CHANGES-1.1971)
> Â Â Â Â Â i686 running cygwin (ix86/GMP-4.2.1 kernel) 32-bit version
> Âcompiled: Dec 23 2007, gcc-3.4.4 (cygming special, gdc 0.12, using dmd
> 0.125)
> Â Â Â Â Â Â Â Â (readline v5.2 enabled, extended help enabled)
>
> Â Â Â Â Â Â Â Â Â Â Copyright (C) 2000-2006 The PARI Group
>
> PARI/GP is free software, covered by the GNU General Public License, and
> comes WITHOUT ANY WARRANTY WHATSOEVER.
>
> Type ? for help, \q to quit.
> Type ?12 for how to get moral (and possibly technical) support.
>
> parisize = 4000000, primelimit = 2000000
> Â realprecision = 19 significant digits (10 digits displayed)
> Â*** znprimroot: bug in PARI/GP (Floating Point Exception), please report
> Goodbye!
>
>
> As requested by the message I am reporting it.
>
> Best Regards,
>
> Kevin.
>
>