Remove TwoTuple.hs.

diff --git a/src/TwoTuple.hs b/src/TwoTuple.hs
deleted file mode 100644 (file)
index becb11e..0000000
--- a/src/TwoTuple.hs
+++ /dev/null
@@ -1,52 +0,0 @@
--- | Implement ordered pairs all over again for fun (and to make sure
---   that we can manipulate them algebraically). Also require (as
---   opposed to the built-in ordered pairs) that the elements have
---   matching types.
---
-module TwoTuple
-where
-
-import Normed
-
-
-data TwoTuple a = TwoTuple a a
-  deriving (Eq)
-
-instance (Show a) => Show (TwoTuple a) where
-  show (TwoTuple x y) = "(" ++ (show x) ++ ", " ++ (show y) ++ ")"
-
-instance Functor TwoTuple where
-  f `fmap` (TwoTuple x1 y1) = TwoTuple (f x1) (f y1)
-
-instance (RealFloat a) => Normed (TwoTuple a) where
-  -- The standard Euclidean 2-norm. We need RealFloat for the square
-  -- root.
-  norm (TwoTuple x y) = fromRational $ toRational (sqrt(x^2 + y^2))
-
-  -- The infinity norm, i.e. the maximum entry.
-  norm_infty (TwoTuple x y) =
-    fromRational $ max absx absy
-    where
-      absx = abs (toRational x)
-      absy = abs (toRational y)
-
--- | It's not correct to use Num here, but I really don't want to have
---   to define my own addition and subtraction.
-instance Num a => Num (TwoTuple a) where
-  -- Standard componentwise addition.
-  (TwoTuple x1 y1) + (TwoTuple x2 y2) =
-    TwoTuple (x1 + x2) (y1 + y2)
-
-  -- Standard componentwise subtraction.
-  (TwoTuple x1 y1) - (TwoTuple x2 y2) =
-    TwoTuple (x1 - x2) (y1 - y2)
-
-  -- Left undefined to prevent mistakes. One sane definition
-  -- would be componentwise multiplication.
-  (*) _ _ = error "multiplication of vectors is undefined"
-
-  abs _ = error "absolute value of vectors is undefined"
-
-  signum _ = error "signum of vectors is undefined"
-
-  fromInteger x = TwoTuple (fromInteger x) (fromInteger x)