Data commit

Task/Feigenbaum-constant-calculation/Haskell/feigenbaum-constant-calculation.hs

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+import Data.List (mapAccumL)
+
+feigenbaumApprox :: Int -> [Double]
+feigenbaumApprox mx = snd $ mitch mx 10
+  where
+    mitch :: Int -> Int -> ((Double, Double, Double), [Double])
+    mitch mx mxj =
+      mapAccumL
+        (\(a1, a2, d1) i ->
+            let a =
+                  iterate
+                    (\a ->
+                        let (x, y) =
+                              iterate
+                                (\(x, y) -> (a - (x * x), 1.0 - ((2.0 * x) * y)))
+                                (0.0, 0.0) !!
+                              (2 ^ i)
+                        in a - (x / y))
+                    (a1 + (a1 - a2) / d1) !!
+                  mxj
+                d = (a1 - a2) / (a - a1)
+            in ((a, a1, d), d))
+        (1.0, 0.0, 3.2)
+        [2 .. (1 + mx)]
+
+-- TEST ------------------------------------------------------------------
+main :: IO ()
+main =
+  (putStrLn . unlines) $
+  zipWith
+    (\i s -> justifyRight 2 ' ' (show i) ++ '\t' : s)
+    [1 ..]
+    (show <$> feigenbaumApprox 13)
+  where
+    justifyRight n c s = drop (length s) (replicate n c ++ s)