A-M baby

Task/Monte-Carlo-methods/Haskell/monte-carlo-methods.hs

@@ -0,0 +1,11 @@
+import System.Random
+import Control.Monad
+
+get_pi throws = do results <- replicateM throws one_trial
+                   return (4 * fromIntegral (foldl' (+) 0 results) / fromIntegral throws)
+  where
+    one_trial = do rand_x <- randomRIO (-1, 1)
+                   rand_y <- randomRIO (-1, 1)
+                   let dist :: Double
+                       dist = sqrt (rand_x*rand_x + rand_y*rand_y)
+                   return (if dist < 1 then 1 else 0)