X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FVector.hs;h=1aaf78daa42e31ca0eae5e106b52aa3827276882;hb=b5bc0c0bc71915093d0883e2fd923808ada4db6c;hp=f55808b33f534283cf7ba432d667c72a6e565353;hpb=6dbbf1130a3318a1cc408f948ac15e74090710ec;p=numerical-analysis.git

diff --git a/src/Vector.hs b/src/Vector.hs
index f55808b..1aaf78d 100644
--- a/src/Vector.hs
+++ b/src/Vector.hs
@@ -15,12 +15,12 @@ import Data.Vector.Fixed (
   N3,
   N4,
   Vector(..),
-  (!),
   construct,
   inspect,
   toList,
   )
 import qualified Data.Vector.Fixed as V (
+  eq,
   foldl,
   length,
   map,
@@ -81,8 +81,8 @@ instance (Show a, Vector v a) => Show (Vn v a) where
 --   >>> v1 == v3
 --   False
 --
-instance (Eq a, Vector v a, Vector v Bool) => Eq (Vn v a) where
-  (Vn v1) == (Vn v2) = V.foldl (&&) True (V.zipWith (==) v1 v2)
+instance (Eq a, Vector v a) => Eq (Vn v a) where
+  (Vn v1) == (Vn v2) = v1 `V.eq` v2
 
 
 -- | The use of 'Num' here is of course incorrect (otherwise, we
@@ -143,7 +143,7 @@ instance (RealFloat a, Ord a, Vector v a) => Normed (Vn v a) where
   --   >>> norm_infty v1
   --   5
   --
-  norm_infty (Vn v1) = fromRational $ toRational $ V.foldl max 0 v1
+  norm_infty (Vn v1) = realToFrac $ V.foldl max 0 v1
 
   -- | Generic p-norms. The usual norm in R^n is (norm_p 2).
   --
@@ -156,7 +156,7 @@ instance (RealFloat a, Ord a, Vector v a) => Normed (Vn v a) where
   --   5.0
   --
   norm_p p (Vn v1) =
-    fromRational $ toRational $ root $ V.sum $ V.map (exponentiate . abs) v1
+    realToFrac $ root $ V.sum $ V.map (exponentiate . abs) v1
     where
       exponentiate = (** (fromIntegral p))
       root = (** (recip (fromIntegral p)))
@@ -191,6 +191,17 @@ angle v1 v2 =
     norms = (norm v1) * (norm v2)
 
 
+-- | Unsafe indexing.
+--
+--   Examples:
+--
+--   >>> let v1 = make2d (1,2)
+--   >>> v1 ! 1
+--   2
+--
+(!) :: (Vector v a) => v a -> Int -> a
+(!) v1 idx = (toList v1) !! idx
+
 -- | Safe indexing.
 --
 --   Examples: