Data commit

Task/Miller-Rabin-primality-test/Run-BASIC/miller-rabin-primality-test.basic

@@ -0,0 +1,55 @@
+input "Input a number:";n
+input "Input test:";k
+
+test =  millerRabin(n,k)
+if test = 0 then
+  print "Probably Prime"
+ else
+  print "Composite"
+end if
+wait
+
+' ----------------------------------------
+' Returns
+'  Composite     = 1
+'  Probably Prime = 0
+' ----------------------------------------
+ FUNCTION millerRabin(n, k)
+  if n = 2 then
+    millerRabin = 0 'probablyPrime
+    goto [funEnd]
+  end if
+
+  if n mod 2 = 0 or n < 2 then
+    millerRabin = 1 'composite
+    goto [funEnd]
+  end if
+
+d = n - 1
+while d mod 2 = 0
+  d = d / 2
+  s = s + 1
+wend
+
+while k > 0
+  k = k - 1
+  base = 2 + int(rnd(1)*(n-3))
+  x = (base^d) mod n
+  if x <> 1 and x <> n-1 then
+    for r=1 To s-1
+      x =(x * x) mod n
+      if x=1 then
+       millerRabin = 1 ' composite
+       goto [funEnd]
+      end if
+      if x = n-1 then exit for
+    next r
+
+    if x<>n-1 then
+      millerRabin =  1 ' composite
+      goto [funEnd]
+    end if
+  end if
+wend
+[funEnd]
+END FUNCTION