2009/6/11 Jeff Gilchrist <jeff.gilchr...@gmail.com> > > On Thu, Jun 11, 2009 at 1:00 PM, gerrob<robert.gerb...@gmail.com> wrote: > > > I've uploaded a new code (wagstaff2.c) in google groups to test > > Wagstaff numbers by Anton Vrba's conjecture. It's faster than > > wagstaff.c from Jeff Gilchrist because I'm using bitshift+bitmask > > instead of the expensive divisions. For example for q=83339 it took me > > 127 sec. while the old code took 516 sec. on my machine, so about 4 > > times speed up. > > Thanks Robert, do you mind if I use your modified code? I just threw > that together without optimization in mind so I appreciate you > speeding it up. > > Jeff. > > > > Yes, you (and also gmp/mpir project) can use/modify my code.
Another improvement would be to use a sieve to eliminate quickly composite numbers: if q>3 prime then it is not hard to prove that all p (prime)divisors of n=(2^q+1)/3 has the p=2*k*q+1 form, where k is an integer. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "mpir-devel" group. To post to this group, send email to mpir-devel@googlegroups.com To unsubscribe from this group, send email to mpir-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/mpir-devel?hl=en -~----------~----~----~----~------~----~------~--~---
