Max Alekseyev on Sat, 25 Mar 2023 19:58:53 +0100


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Re: polrootsmod(f,p) with f%p==0


Well, there will be a memory allocation error in this case, but it'll work fine in many other cases with small p. 
I'd prefer to see a memory error in the case of large p rather than the "zero polynomial in FpX_roots" error unconditionally.
Regards,
Max

On Sat, Mar 25, 2023 at 2:36 PM Bill Allombert <Bill.Allombert@math.u-bordeaux.fr> wrote:
On Sat, Mar 25, 2023 at 12:46:49PM -0400, Max Alekseyev wrote:
> Shouldn't polrootsmod(f,p) for a prime p and f%p==0 simply return
> vector(p,i,Mod(i-1,p)) instead of the error?

Given that p can be arbitrarily large, this is not practical...
Just consider polrootsmod(0*x,2^127-1)

Cheers,
Bill