Editing GHC/Data Parallel Haskell/Package NDP (section)

=== A small example ===

The following module implements the dot product of two vectors with package ndp:

<haskell>
module DotP_ndp (dotp)
where

import Data.Array.Parallel.Unlifted

dotp :: (Num a, UA a) => UArr a -> UArr a -> a
dotp xs ys = sumU (zipWithU (*) xs ys)
</haskell>

We can also use that in an interactive GHCi session:

<blockquote><pre>
Prelude> :set -package ndp
package flags have changed, ressetting and loading new packages...
Loading package ndp-1.0 ... linking ... done.
Prelude> :l /home/chak/code/haskell/DotP_ndp
[1 of 1] Compiling DotP_ndp         ( /home/chak/code/haskell/DotP_ndp.hs, interpreted )
Ok, modules loaded: DotP_ndp.
*DotP_ndp> dotp (toU [1..3]) (toU [4..6])
Loading package haskell98 ... linking ... done.
32.0
*DotP_ndp>
</pre></blockquote>

Most of the functions under  are still purely sequential, albeit '''much''' more efficient than <tt>GHC.PArr</tt>.  In addition, the (currently only few) functions from [http://darcs.haskell.org/packages/ndp/Data/Array/Parallel/Unlifted/Parallel.hs <tt>Data.Array.Parallel.Unlifted.Parallel</tt>] ''transparently'' use multiple processing elements if GHC was compiled with SMP multiprocessor support.