Drop the 'column' function that returned a vector instead of a matrix.

[numerical-analysis.git] / src / Linear / Matrix.hs

diff --git a/src/Linear/Matrix.hs b/src/Linear/Matrix.hs
index 054bb6e3afac2777ef16e200ff64b9c60a9fd3fd..6d13a693b71e37631e8600f87652f6c9eb73b883 100644 (file)
--- a/src/Linear/Matrix.hs
+++ b/src/Linear/Matrix.hs
@@ -188,24 +188,23 @@ row' m i =
 
 
 -- | Return the @j@th column of @m@. Unsafe.
-column :: Mat m n a -> Int -> (Vec m a)
-column (Mat rows) j =
-  V.map (element j) rows
-  where
-    element = flip (!)
+--column :: Mat m n a -> Int -> (Vec m a)
+--column (Mat rows) j =
+--  V.map (element j) rows
+--  where
+--    element = flip (!)
 
 
 -- | Return the @j@th column of @m@ as a matrix. Unsafe.
-column' :: (Arity m, Arity n) => Mat m n a -> Int -> Col m a
-column' m j =
+column :: (Arity m, Arity n) => Mat m n a -> Int -> Col m a
+column m j =
   construct lambda
   where
     lambda i _ = m !!! (i, j)
 
 
 -- | Transpose @m@; switch it's columns and its rows. This is a dirty
---   implementation.. it would be a little cleaner to use imap, but it
---   doesn't seem to work.
+--   implementation, but I don't see a better way.
 --
 --   TODO: Don't cheat with fromList.
 --
@@ -216,9 +215,10 @@ column' m j =
 --   ((1,3),(2,4))
 --
 transpose :: (Arity m, Arity n) => Mat m n a -> Mat n m a
-transpose m = Mat $ V.fromList column_list
+transpose matrix =
+  construct lambda
   where
-    column_list = [ column m i | i <- [0..(ncols m)-1] ]
+    lambda i j = matrix !!! (j,i)
 
 
 -- | Is @m@ symmetric?