From: Michael Orlitzky <michael@orlitzky.com>
Date: Wed, 5 Feb 2014 01:33:09 +0000 (-0500)
Subject: Add zipcol and matmap functions in Linear.Matrix.
X-Git-Url: http://gitweb.michael.orlitzky.com/?p=numerical-analysis.git;a=commitdiff_plain;h=26b7d3e4333fd2f36961b00861952f2a63a0eaba

Add zipcol and matmap functions in Linear.Matrix.
---

diff --git a/src/Linear/Matrix.hs b/src/Linear/Matrix.hs
index 34920b4..7c0f84a 100644
--- a/src/Linear/Matrix.hs
+++ b/src/Linear/Matrix.hs
@@ -767,3 +767,34 @@ trace matrix =
   let (Mat rows) = diagonal matrix
   in
     element_sum $ V.map V.head rows
+
+
+-- | Zip together two column matrices.
+--
+--   Examples:
+--
+--   >>> let m1 = fromList [[1],[1],[1]] :: Col3 Int
+--   >>> let m2 = fromList [[1],[2],[3]] :: Col3 Int
+--   >>> zipcol m1 m2
+--   (((1,1)),((1,2)),((1,3)))
+--
+zipcol :: Arity m => Col m a -> Col m a -> Col m (a,a)
+zipcol c1 c2 =
+  construct lambda
+  where
+    lambda i j = (c1 !!! (i,j), c2 !!! (i,j))
+
+
+-- | Map a function over a matrix of any dimensions.
+--
+--   Examples:
+--
+--   >>> let m = fromList [[1,2],[3,4]] :: Mat2 Int
+--   >>> matmap (^2) m
+--   ((1,4),(9,16))
+--
+matmap :: (a -> b) -> Mat m n a -> Mat m n b
+matmap f (Mat rows) =
+  Mat $ V.map g rows
+  where
+    g = V.map f