import Data.List (find)
-import Vector
+import Normed
has_root :: (Fractional a, Ord a, Ord b, Num b)
--
-- We also return the number of iterations required.
--
-fixed_point_with_iterations :: (Vector a, RealFrac b)
+fixed_point_with_iterations :: (Normed a, RealFrac b)
=> (a -> a) -- ^ The function @f@ to iterate.
-> b -- ^ The tolerance, @epsilon@.
-> a -- ^ The initial value @x0@.