On Wed, 9 Aug 1995, Ray Cromwell wrote:
Nathan Zook wrote:
don't have a GNU ftp site to hand.
There's a function
int mpz_probab_prime_p(mpnum, SURETY)
which returns true if the prime passes SURETY probablistic prime tests.
I think if it passes say 25 tests, then there will be less than a 1/2^25 chance that it is not prime.
Also, on:
The proper thing to do is to then search for a number which demonstrates p is prime....
And how do you do this? I'm not aware of any deterministic primality test which isn't atleast as hard as factoring. P-1 factorial is such a number which could demonstrate P is prime (compute the gcd, check if they are relatively prime). Good luck computing it.
-Ray
Common, Ray! floor(sqrt(p))! would work fine.... ;-) Seriously, at least 1/4 of the numbers between can p and 0 prove that p is prime. So you try for a while. If you don't get it, you can flip back. I apologize for being so vague. I don't have the paper I read a couple years ago in front of me. You might contact your local math department & ask... Nathan