A-M baby

Task/Miller-Rabin-primality-test/C/miller-rabin-primality-test-1.c

@@ -0,0 +1,5 @@
+#ifndef _MILLER_RABIN_H_
+#define _MILLER_RABIN_H
+#include <gmp.h>
+bool miller_rabin_test(mpz_t n, int j);
+#endif

Task/Miller-Rabin-primality-test/C/miller-rabin-primality-test-2.c

@@ -0,0 +1,63 @@
+#include <stdbool.h>
+#include <gmp.h>
+#include "primedecompose.h"
+
+#define MAX_DECOMPOSE 100
+
+bool miller_rabin_test(mpz_t n, int j)
+{
+  bool res;
+  mpz_t f[MAX_DECOMPOSE];
+  mpz_t s, d, a, x, r;
+  mpz_t n_1, n_3;
+  gmp_randstate_t rs;
+  int l=0, k;
+
+  res = false;
+  gmp_randinit_default(rs);
+
+  mpz_init(s); mpz_init(d);
+  mpz_init(a); mpz_init(x); mpz_init(r);
+  mpz_init(n_1); mpz_init(n_3);
+
+  if ( mpz_cmp_si(n, 3) <= 0 ) { // let us consider 1, 2, 3 as prime
+    gmp_randclear(rs);
+    return true;
+  }
+  if ( mpz_odd_p(n) != 0 ) {
+    mpz_sub_ui(n_1, n, 1);         //  n-1
+    mpz_sub_ui(n_3, n, 3);         //  n-3
+    l = decompose(n_1, f);
+    mpz_set_ui(s, 0);
+    mpz_set_ui(d, 1);
+    for(k=0; k < l; k++) {
+      if ( mpz_cmp_ui(f[k], 2) == 0 )
+	mpz_add_ui(s, s, 1);
+      else
+	mpz_mul(d, d, f[k]);
+    }                             // 2^s * d = n-1
+    while(j-- > 0) {
+      mpz_urandomm(a, rs, n_3);     // random from 0 to n-4
+      mpz_add_ui(a, a, 2);          // random from 2 to n-2
+      mpz_powm(x, a, d, n);
+      if ( mpz_cmp_ui(x, 1) == 0 ) continue;
+      mpz_set_ui(r, 0);
+      while( mpz_cmp(r, s) < 0 ) {
+	if ( mpz_cmp(x, n_1) == 0 ) break;
+	mpz_powm_ui(x, x, 2, n);
+	mpz_add_ui(r, r, 1);
+      }
+      if ( mpz_cmp(x, n_1) == 0 ) continue;
+      goto flush; // woops
+    }
+    res = true;
+  }
+
+flush:
+  for(k=0; k < l; k++) mpz_clear(f[k]);
+  mpz_clear(s); mpz_clear(d);
+  mpz_clear(a); mpz_clear(x); mpz_clear(r);
+  mpz_clear(n_1); mpz_clear(n_3);
+  gmp_randclear(rs);
+  return res;
+}

Task/Miller-Rabin-primality-test/C/miller-rabin-primality-test-3.c

@@ -0,0 +1,29 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <gmp.h>
+#include "miller-rabin.h"
+
+#define PREC 10
+#define TOP  4000
+
+int main()
+{
+  mpz_t num;
+
+  mpz_init(num);
+  mpz_set_ui(num, 1);
+
+  while ( mpz_cmp_ui(num, TOP) < 0 ) {
+    if ( miller_rabin_test(num, PREC) ) {
+      gmp_printf("%Zd maybe prime\n", num);
+    } /*else {
+      gmp_printf("%Zd not prime\n", num);
+      }*/ // remove the comment iff you're interested in
+          // sure non-prime.
+    mpz_add_ui(num, num, 1);
+  }
+
+  mpz_clear(num);
+  return EXIT_SUCCESS;
+}