1 files changed, 32 insertions, 1 deletions

diff --git a/lib/Numeric/LinearAlgebra/Linear.hs b/lib/Numeric/LinearAlgebra/Linear.hs
index 8922e51..9a7e65f 100644
--- a/lib/Numeric/LinearAlgebra/Linear.hs
+++ b/lib/Numeric/LinearAlgebra/Linear.hs
@@ -16,11 +16,15 @@ Basic optimized operations on vectors and matrices.
 -----------------------------------------------------------------------------
 
 module Numeric.LinearAlgebra.Linear (
+    -- * Linear Algebra Typeclasses
     Vectors(..),                                    
-    Linear(..)
+    Linear(..),
+    -- * Creation of numeric vectors
+    constant, linspace
 ) where
 
 import Data.Packed.Internal.Vector
+import Data.Packed.Internal.Matrix
 import Data.Packed.Matrix
 import Data.Complex
 import Numeric.GSL.Vector
@@ -29,6 +33,7 @@ import Control.Monad(ap)
 
 -- | basic Vector functions
 class Num e => Vectors a e where
+    -- the C functions sumX are twice as fast as using foldVector
     vectorSum :: a e -> e
     euclidean :: a e -> e
     absSum    :: a e -> e
@@ -153,3 +158,29 @@ instance (Linear Vector a, Container Matrix a) => (Linear Matrix a) where
     divide = liftMatrix2 divide
     equal a b = cols a == cols b && flatten a `equal` flatten b
     scalar x = (1><1) [x]
+
+
+----------------------------------------------------
+
+{- | creates a vector with a given number of equal components:
+
+@> constant 2 7
+7 |> [2.0,2.0,2.0,2.0,2.0,2.0,2.0]@
+-}
+constant :: Element a => a -> Int -> Vector a
+-- constant x n = runSTVector (newVector x n)
+constant = constantD -- about 2x faster
+
+{- | Creates a real vector containing a range of values:
+
+@\> linspace 5 (-3,7)
+5 |> [-3.0,-0.5,2.0,4.5,7.0]@
+
+Logarithmic spacing can be defined as follows:
+
+@logspace n (a,b) = 10 ** linspace n (a,b)@
+-}
+linspace :: (Enum e, Linear Vector e) => Int -> (e, e) -> Vector e
+linspace n (a,b) = addConstant a $ scale s $ fromList [0 .. fromIntegral n-1]
+    where s = (b-a)/fromIntegral (n-1)
+