Improve prime check algorithm

Signed-off-by: trivernis <trivernis@protonmail.com>
4 years ago · f1c9948b07
parent 7762d06987
commit f1c9948b07
1 changed files with 2 additions and 2 deletions
--- a/src/kernel_controller/kernel.cl
+++ b/src/kernel_controller/kernel.cl
@ -23,8 +23,8 @@ __kernel void check_prime(const int LOWER_PRIME_COUNT, __global const int *LOWER
            }
        }
        if (prime && LOWER_PRIMES[LOWER_PRIME_COUNT - 1] < num) {
-            for (long i = LOWER_PRIMES[LOWER_PRIME_COUNT - 1]; i <= sqrt((double) num); i += 2) {
-                if (num % i == 0) {
+            for (long i = LOWER_PRIMES[LOWER_PRIME_COUNT - 1]; i <= sqrt((double) num); i += 6) {
+                if (num % (i - 2) == 0 || num % (i - 4) == 0) {
                    prime = false;
                    break;
                }