From 9ef91ad4ec3a5c0966f0850d40310722b6c38b68 Mon Sep 17 00:00:00 2001
From: Michael Orlitzky <michael@orlitzky.com>
Date: Fri, 7 Feb 2014 19:10:02 -0500
Subject: [PATCH] Remove the "row" function which returned a vector instead of
 a matrix.

---
 src/Integration/Gaussian.hs |  4 ++--
 src/Linear/Matrix.hs        | 33 +++++++++++----------------------
 2 files changed, 13 insertions(+), 24 deletions(-)

diff --git a/src/Integration/Gaussian.hs b/src/Integration/Gaussian.hs
index 38214a0..be92e5c 100644
--- a/src/Integration/Gaussian.hs
+++ b/src/Integration/Gaussian.hs
@@ -29,7 +29,7 @@ import Linear.Matrix (
   fromList,
   identity_matrix,
   map2,
-  row',
+  row,
   transpose )
 import Linear.QR ( eigenvectors_symmetric )
 import Normed ( Normed(..) )
@@ -119,7 +119,7 @@ nodes_and_weights iterations =
     nodes = shifted_nodes + ones -- unshift the nodes
 
     -- Get the first component of each column.
-    first_components = row' vecs 0
+    first_components = row vecs 0
 
     -- Square it and multiply by 2; see the Golub-Welsch paper for
     -- this magic.
diff --git a/src/Linear/Matrix.hs b/src/Linear/Matrix.hs
index 6d13a69..a5fbb84 100644
--- a/src/Linear/Matrix.hs
+++ b/src/Linear/Matrix.hs
@@ -152,49 +152,37 @@ fromList vs = Mat (V.fromList $ map V.fromList vs)
 
 -- | Unsafe indexing.
 (!!!) :: (Arity m, Arity n) => Mat m n a -> (Int, Int) -> a
-(!!!) m (i, j) = (row m i) ! j
+(!!!) (Mat rows) (i, j) = (rows ! i) ! j
+
 
 -- | Safe indexing.
-(!!?) :: Mat m n a -> (Int, Int) -> Maybe a
-(!!?) m@(Mat rows) (i, j)
+(!!?) :: (Arity m, Arity n) => Mat m n a -> (Int, Int) -> Maybe a
+(!!?) matrix (i, j)
   | i < 0 || j < 0 = Nothing
-  | i > V.length rows = Nothing
-  | otherwise = if j > V.length (row m j)
-                then Nothing
-                else Just $ (row m j) ! j
+  | i > (nrows matrix) - 1 = Nothing
+  | j > (ncols matrix) - 1 = Nothing
+  | otherwise = Just $ matrix !!! (i,j)
 
 
 -- | The number of rows in the matrix.
 nrows :: forall m n a. (Arity m) => Mat m n a -> Int
 nrows _ = arity (undefined :: m)
 
+
 -- | The number of columns in the first row of the
 --   matrix. Implementation stolen from Data.Vector.Fixed.length.
 ncols :: forall m n a. (Arity n) => Mat m n a -> Int
 ncols _ = arity (undefined :: n)
 
 
--- | Return the @i@th row of @m@. Unsafe.
-row :: Mat m n a -> Int -> (Vec n a)
-row (Mat rows) i = rows ! i
-
-
 -- | Return the @i@th row of @m@ as a matrix. Unsafe.
-row' :: (Arity m, Arity n) => Mat m n a -> Int -> Row n a
-row' m i =
+row :: (Arity m, Arity n) => Mat m n a -> Int -> Row n a
+row m i =
   construct lambda
   where
     lambda _ j = m !!! (i, j)
 
 
--- | 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 (!)
-
-
 -- | 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 =
@@ -270,6 +258,7 @@ identity_matrix :: (Arity m, Ring.C a) => Mat m m a
 identity_matrix =
   construct (\i j -> if i == j then (fromInteger 1) else (fromInteger 0))
 
+
 -- | Given a positive-definite matrix @m@, computes the
 --   upper-triangular matrix @r@ with (transpose r)*r == m and all
 --   values on the diagonal of @r@ positive.
-- 
2.44.2