Data commit

Task/Miller-Rabin-primality-test/ALGOL-68/miller-rabin-primality-test.alg

@@ -0,0 +1,38 @@
+MODE LINT=LONG INT;
+MODE LOOPINT = INT;
+
+MODE POWMODSTRUCT = LINT;
+PR READ "prelude/pow_mod.a68" PR;
+
+PROC miller rabin = (LINT n, LOOPINT k)BOOL: (
+    IF n<=3 THEN TRUE
+    ELIF NOT ODD n THEN FALSE
+    ELSE
+        LINT d := n - 1;
+        INT s := 0;
+        WHILE NOT ODD d DO
+            d := d OVER 2;
+            s +:= 1
+        OD;
+        TO k DO
+            LINT a := 2 + ENTIER (random*(n-3));
+            LINT x :=  pow mod(a, d, n);
+            IF x /= 1 THEN
+                TO s DO
+                    IF x = n-1 THEN done FI;
+                    x := x*x %* n
+                OD;
+                else: IF x /= n-1 THEN return false FI;
+                done: EMPTY
+            FI
+        OD;
+        TRUE EXIT
+        return false: FALSE
+    FI
+);
+
+FOR i FROM 937 TO 1000 DO
+  IF miller rabin(i, 10) THEN
+    print((" ",whole(i,0)))
+  FI
+OD