Karim Belabas on Thu, 08 May 2014 23:00:36 +0200 |
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Re: Factoring small numbers |
* Bill Allombert [2014-05-08 22:17]: > On Thu, May 08, 2014 at 08:49:58PM +0200, Karim Belabas wrote: > > * Jeroen Demeyer [2014-05-08 18:40]: > > Benchmarking the factorization of a single small integer is not very > > useful. Can you try a set of about 1000 "random" integers of the same > > size ? (and share your benchmark code :-) > > > > You can play with > > > > factor(a, n) \\ that's for trial division > > factorint(a, combinations of flags 1/2/4/8) > > > > to see if disabling particular factorization engines helps. > > It does not. (As I reported. Was just suggesting ways to investigate in case something interesting turned up in Jeroen's bench.) > Also > \g3 > factorint(2131130266423999109,1) > still call MPQS. That's why I asked for 65-bit integers, since smaller integers are delegated to factoru() which has not 'hint' argument and ignores factorint flags. Should be documented, but I've been of two minds with this; fixing the discrepancy is not hard and might be better than documenting it. You requested it a few times for bounded factorization ( factor(a,n) ) as well. Cheers, K.B. -- Karim Belabas, IMB (UMR 5251) Tel: (+33) (0)5 40 00 26 17 Universite Bordeaux 1 Fax: (+33) (0)5 40 00 69 50 351, cours de la Liberation http://www.math.u-bordeaux1.fr/~kbelabas/ F-33405 Talence (France) http://pari.math.u-bordeaux1.fr/ [PARI/GP] `