Re: Possible bug in znprimroot

[John Cremona <john.cremona@gmail.com>]

On 12 January 2011 13:05, Bill Allombert
<Bill.Allombert@math.u-bordeaux1.fr> wrote:
> On Wed, Jan 12, 2011 at 03:00:14AM -0500, Max Alekseyev wrote:
>> 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.
>
> Agreed, but this only onccurs with PARI 2.4.2. With PARI 2.4.3, this results in an
> infinite loop instead. This is in line with the documentation that state that:
>
>  If the group is not cyclic,  the result  is undefined.
>

"undefined" and causing an infinite loop are rather different!  Surely
no reasonable (even wrong) input should cause an infinite loop?

John

> Cheers,
> Bill.
>