Bill Allombert on Thu, 3 Apr 2003 22:42:54 +0200


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Re: polredabs() again


On Wed, Mar 12, 2003 at 03:09:12PM -0500, Igor Schein wrote:
> Hi,
> 
> I know there're too many things going on at the same time right now,
> but I'll still gonna mention this example of polredabs() inefficiency:
> 
> polredabs(x^8-97418273277417164826810*x^4-97418273278115084139045*x^2+97418273278115084139045);
> 
> It takes extremely long time.  Basically, I'd like to see either a
> quick fix ( if possible ) or an acknowledgement of the issue in TODO
> file :).  I know we've discussed this with Karim in private emails,
> but it never made it into TODO.  

[I was expecting Karim to comment but...]

Well, the underlying algorithm has a high complexity, so it is not clear
it is a defficiency in PARI or even that it is fixable, if we insist
to have the 'absolutly smallest polynomial'.

Do you have experienced with other implementation (Kant OrderShort
function ?)

Cheers,
Bill.