quote:Original post by CodeJunkie
(3-1)! = 2!
2+1 = 3
3/3 = 0
What math universe do you live in?
did i just break RSA?
quote:Original post by rypyr
What math universe do you live in?
lol
/ == -
- == +
+ == *
* == /
maybe thats why i fail all my math classes
So assuming that mod change fixes it, we''re back to the original problem: This algorithm can only test numbers up to about 12 on a 32-bit machine...maybe you''ll get as far as 25 on a 64-bit machine.
It''s the little things that kill...
Besides I think you can test to up to prime 13 before the data type overflows.(my bad)
Besides I think you can test to up to prime 13 before the data type overflows.(my bad)
Improved:
bool Primality(ulong n){ ulong modfact = 1; for (ulong i = 2; i < n; ++i) modfact = (modfact * i) % n; return modfact == n - 1;}
Do you mean return False?
n=6 (not a prime)
modfact = 1
i=2; modfact = 2;(1*2)%6
i=3; modfact = 0;(2*3)%6
Yes this method is much improved. Now it can handle N somewhere up to ((2^32)^1/2)-1. (I think)
n=6 (not a prime)
modfact = 1
i=2; modfact = 2;(1*2)%6
i=3; modfact = 0;(2*3)%6
Yes this method is much improved. Now it can handle N somewhere up to ((2^32)^1/2)-1. (I think)
Author
the algorithm works properly becasue (n-1)! + 1 is a mutiple of n thus if it is divisble by n evenly it is a prime number thus (n-1)! +1 % n == 0 is a testing case that is correct. i was posting to access the speed of the function and where to get larger number libraries to use it with alger numbers as people have stated n = 13 is highest it works for because of overflow. please dont bash me unless you know what you are talking about thank you 
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