-#include <time.h>
#include <stdio.h>
#include <string.h>
-#include <stdint.h>
#include <stdbool.h>
+#include <pthread.h>
+#include <time.h>
+
#include <gmp.h>
+/* the real test (max complete n=36576908*/
+//#define K_CONST 21181
+//#define N_CONST 44200000
+//#define N_CONST 36576908
-bool is_prime(mpz_t p);
-bool is_prime2(mpz_t p);
+/* recent find (k=46157, n=698207)*/
+//#define K_CONST 46157
+//#define N_CONST 698203
-clock_t start;
+/* searching for k=301, n=7360 */
+#define K_CONST 301
+#define N_CONST 6500
+#define NUM_CORES 6
-//ints for is_prime test
-mpz_t t_exp;
-mpz_t t_p1;
-mpz_t t_p2;
-mpz_t t_p3;
-mpz_t t;
+static void * proth_thread(void *arg);
+//mutex protected, thread safe n
+unsigned long int n_val = N_CONST;
+pthread_mutex_t n_lock;
+pthread_mutex_t found_lock;
int main(void)
{
- mpz_t exp;
- mpz_t p;
- mpz_t k;
- mpz_t base;
+ time_t start;
+ time_t end;
+ time(&start);
- mpz_init(p);
+ //array to keep track of the thread id's
+ pthread_t thread_ids[NUM_CORES];
- mpz_init(k);
- mpz_init(exp);
- mpz_init(base);
+ //create the mutexes
+ pthread_mutex_init(&n_lock, NULL);
+ pthread_mutex_init(&found_lock, NULL);
- mpz_init(t_exp);
- mpz_init(t_p1);
- mpz_init(t_p2);
- mpz_init(t_p3);
- mpz_init(t);
+ //create the threads
+ for(int i = 0; i < NUM_CORES; i++)
+ {
+ pthread_create(&thread_ids[i], NULL, &proth_thread, NULL);
+ }
- //first 3 primes
- mpz_set_ui(t_p1, 2);
- mpz_set_ui(t_p2, 3);
- mpz_set_ui(t_p3, 5);
+ //lock main thread until prime is found
+ pthread_mutex_lock(&found_lock);
+ pthread_mutex_lock(&found_lock);
- //start = clock();
+ //destroy the threads
+ for(int i = 0; i < NUM_CORES; i++)
+ {
+ pthread_cancel(thread_ids[i]);
+ }
+ //destroy the mutexes
+ pthread_mutex_destroy(&n_lock);
+ pthread_mutex_destroy(&found_lock);
- //proth number is k*2^n+1
- //check where k is 19
- mpz_set_ui(k, 46157);
+ time(&end);
+ printf("total time: %f seconds\n", difftime(end, start));
+}
- //calc 2^n
- mpz_set_ui(base, 2);
+unsigned long get_n()
+{
+ pthread_mutex_lock(&n_lock);
+ unsigned long n = n_val;
+ n_val++;
+ pthread_mutex_unlock(&n_lock);
+ return n;
+}
- for(unsigned long int n = 698200; ; n++)
- {
- mpz_pow_ui(exp, base, n);
+static void * proth_thread(void *arg)
+{
+ //proth number is p=k*2^n+1
+ unsigned long int n;
+
+ // variables to calculate the proth number: p=k*2^n+1
+ mpz_t proth; // the proth number
+ mpz_t p_minus1; // the proth number minus 1
+ mpz_t k; // k
+ mpz_t two; // 2
+ mpz_t two_n; // 2^n
+
+ // variables to test the primality: t = a^((p-1)/2) % p
+ mpz_t t;
+ mpz_t a1;
+ mpz_t a2;
+ mpz_t a_exp;
+
+ //initialize the variables
+ mpz_init(proth);
+ mpz_init(p_minus1);
+ mpz_init(k);
+ mpz_init(two);
+ mpz_init(two_n);
+ mpz_init(t);
+ mpz_init(a1);
+ mpz_init(a2);
+ mpz_init(a_exp);
+
+ mpz_set_ui(a1, 3);
+ mpz_set_ui(a2, 5);
+
+ //proth number is p=k*2^n+1
+ //set the k constant
+ mpz_set_ui(k, K_CONST);
+ //set two=2
+ mpz_set_ui(two, 2);
- //p=k*2^n
- mpz_mul(p, k, exp);
- //p+=1
- mpz_add_ui(p, p, 1);
+ while (1)
+ {
+ //get the thread-safe n
+ n = get_n();
+ printf("(n=%lu)\n", n);
+
+ //Step 1: Caluclate the Proth Number
+ //calc exp=2^n
+ mpz_pow_ui(two_n, two, n);
+ //calc p=k*2^n
+ mpz_mul(p_minus1, k, two_n);
+ //calc p=k*2^n+1 (this is our proth number)
+ mpz_add_ui(proth, p_minus1, 1);
+
+ //Step 2: Check if the Proth Number is Prime
+ //the prime check exponent is (p-1)/2
+ mpz_divexact_ui(a_exp, p_minus1, 2);
+
+ //printf("prime check a=3\n");
+ mpz_powm(t, a1, a_exp, proth);
+ mpz_add_ui(t, t, 1);
+ if(mpz_cmp(t, proth) == 0)
+ {
+ printf("prime with a=3!\n");
+ break;
+ }
- gmp_printf("(n=%d)\n%Zd\n\n", n, p);
- if(is_prime2(p) == true)
+ //printf("prime check a=5\n");
+ mpz_powm(t, a2, a_exp, proth);
+ mpz_add_ui(t, t, 1);
+ if(mpz_cmp(t, proth) == 0)
{
- printf(" <--- prime\n");
- return 1;
+ printf("prime with a=5!\n");
+ break;
}
- printf("\n");
}
- //free p
- mpz_clear(p);
-}
-
-bool is_prime(mpz_t p)
-{
- //exponent is (p-1)/2
- //printf("exp\n");
- mpz_sub_ui(t_exp, p, 1);
- mpz_divexact_ui(t_exp, t_exp, 2);
- unsigned long int ui_exp = mpz_get_ui(t_exp);
-
- //printf("pow1\n");
- mpz_pow_ui(t, t_p1, ui_exp);
- mpz_add_ui(t, t, 1);
- //printf("div1\n");
- if(mpz_divisible_p(t, p) != 0)
- return true;
-
- //printf("pow2\n");
- mpz_pow_ui(t, t_p2, ui_exp);
- mpz_add_ui(t, t, 1);
- //printf("div2\n");
- if(mpz_divisible_p(t, p) != 0)
- return true;
-
- //printf("pow3\n");
- mpz_pow_ui(t, t_p3, ui_exp);
- mpz_add_ui(t, t, 1);
- //printf("div3\n");
- if(mpz_divisible_p(t, p) != 0)
- return true;
-
- return false;
-}
-
-bool is_prime2(mpz_t p)
-{
- //exponent is (p-1)/2
- printf("exp\n");
- mpz_sub_ui(t_exp, p, 1);
- mpz_divexact_ui(t_exp, t_exp, 2);
-
- printf("pow1\n");
- mpz_powm(t, t_p1, t_exp, p);
- mpz_add_ui(t, t, 1);
- printf("cmp1\n");
- if(mpz_cmp(t, p) == 0)
- return true;
-
- printf("pow2\n");
- mpz_powm(t, t_p2, t_exp, p);
- mpz_add_ui(t, t, 1);
- printf("cmp2\n");
- if(mpz_cmp(t, p) == 0)
- return true;
-
- printf("pow3\n");
- mpz_powm(t, t_p3, t_exp, p);
- mpz_add_ui(t, t, 1);
- printf("cmp3\n");
- if(mpz_cmp(t, p) == 0)
- return true;
-
- return false;
+ //proth number is k*2^n+1
+ gmp_printf("%Zd*2^%llu+1 is prime!\n", k, n);
+
+ //free
+ mpz_clear(proth);
+ mpz_init(p_minus1);
+ mpz_clear(k);
+ mpz_clear(two);
+ mpz_clear(two_n);
+ mpz_clear(t);
+ mpz_clear(a1);
+ mpz_clear(a2);
+ mpz_clear(a_exp);
+
+ FILE *fp = fopen("proth_file", "w");
+ fprintf(fp, "%lu\n", n);
+ fclose(fp);
+
+ pthread_mutex_unlock(&found_lock);
+
+ return NULL;
}