Re: slow factor

[Bill Allombert <Bill.Allombert@math.u-bordeaux.fr>]

On Wed, May 04, 2022 at 08:20:53PM +0800, Zhao Li wrote:
> Thank you.
> 
> It looks that the priority really matters. However, how should we
> determine which one has higher priority, since we have seen another
> example which can be only be solved when ieta has higher priority. 

Yet another bug to fix. Try this function:

fact(P) =
{
  my(x=variable(P),y=variable(Vec(P)));
  my(d=poldegree(P,y)+1);
  my(C=content(P),FC=factor(C));
  for(i=1,oo,
    my(R=substpol(factor(subst(P/C,y,(x+i)^d)),(x+i)^d,y));
    R= matconcat([FC,R]~);
    my(F=factorback(R));
    if(pollead(P)*F==pollead(F)*P,
      return(R));
  );
}

Cheers,
Bill