Subj : Re: Faster algorithm for prim numbers..!!
To   : comp.programming
From : websnarf
Date : Wed Sep 21 2005 07:49 pm

Steve O'Hara-Smith wrote:
> "Robert Bralic" <robo_bralic@yahoo.co.uk> wrote:
> > I weated a simple program, he is compiled
> > with gcc, and generates prim numbers,
> > with fastes method that I find.He is based
> > on divide with generated prim numbers...
> > At end he gives time report on format:
> > dd:hh:mi:sec...
> > Precompile as gcc prim.c -o prim, and use
> > him as "prim upper_bound",as example:
> > "prim 1000".If anybody have some idea
> > how to make algorithm fastes write to me...!!
>
> 	http://en.wikipedia.org/wiki/Sieve_of_Eratosthenes
> and
> 	http://en.wikipedia.org/wiki/Sieve_of_Atkin

That's fine if you want that set of primes between 1 and x.  But if you
want to check a random number for primality, or you want to nth prime,
up to 32 bits, try this:

    http://www.pobox.com/~qed/primeat.zip

--
Paul Hsieh
http://www.pobox.com/~qed/ninja.html
http://bstring.sf.net/

.