Data update

Task/Totient-function/Miranda/totient-function.miranda

@@ -0,0 +1,25 @@
+main :: [sys_message]
+main = [Stdout (lay (map showline [1..25])),
+        Stdout (lay (map countprimes (25:map (10^) [2..5])))]
+
+countprimes :: num->[char]
+countprimes n = "There are " ++ show amount ++ " primes up to " ++ show n
+                where amount = #filter prime [2..n]
+
+showline :: num->[char]
+showline n = "phi(" ++ show n ++ ") = " ++ show (totient n) ++ ", " ++ kind
+             where kind = "prime", if prime n
+                        = "composite", otherwise
+
+prime :: num->bool
+prime n = totient n = n - 1
+
+totient :: num->num
+totient n = loop n n (2:[3, 5..])
+            where loop tot n (d:ds)
+                   = tot, if n<=1
+                   = tot - tot div n, if d*d > n
+                   = loop tot n ds, if n mod d ~= 0
+                   = loop (tot - tot div d) (remfac n d) ds, otherwise
+                  remfac n d = n, if n mod d ~= 0
+                             = remfac (n div d) d, otherwise