> ifactor(6427752177035961102167848369947769686193797499819654815690533);
(2535301200456458802993406410901)
>
This takes a long time for Maple to factor this number.
DERIVE does it in less than a second.
I guess I need to try NTL and MPFR.
Thank you, Jim FitzSimons
_____
From: maxima-admin at math.utexas.edu [mailto:maxima-admin at math.utexas.edu] On
Behalf Of Richard Fateman
Sent: Tuesday, June 13, 2006 8:22 AM
To: Jim FitzSimons; Maxima at math.utexas.edu
Subject: Re: [Maxima] factor(2^101-1)=???
If all you want to do is factor integers, there are programs to do
this, and a bunch of other number-theoretic calculations, and usually not
so much else. Shoup's NTL and the MPFR project come to mind.
While adding better integer factoring programs to Maxima is
harmless, it is not the major thrust of Maxima. (My own approach
to this is to have Lisp just call NTL or MPFR.) I don't know what
ifactor does. I think the plausible heuristics include a quick search
for small factors followed by an attempt to prove the number is
prime. And then something else that is the subject of much
research.
See
en.wikipedia.org/wiki/Integer_factorization