4 files changed, 45 insertions, 4 deletions

diff --git a/examples/vector.hs b/examples/vector.hs
new file mode 100644
index 0000000..12cbc42
--- /dev/null
+++ b/examples/vector.hs
@@ -0,0 +1,29 @@
+-- conversion to/from Data.Vector.Storable
+-- from Roman Leshchinskiy "vector" package
+--
+-- In the future Data.Packed.Vector will be replaced by Data.Vector.Storable
+
+-------------------------------------------
+
+import Data.Packed as H
+import Data.Packed.Development(unsafeFromForeignPtr, unsafeToForeignPtr)
+import Foreign.Storable
+import qualified Data.Vector.Storable as V
+
+fromVector :: Storable t => V.Vector t -> H.Vector t
+fromVector v = unsafeFromForeignPtr p i n where
+    (p,i,n) = V.unsafeToForeignPtr (V.copy v)
+
+toVector :: H.Vector t -> V.Vector t
+toVector v = V.unsafeFromForeignPtr p i n where
+    (p,i,n) = unsafeToForeignPtr v
+
+-------------------------------------------
+
+v = V.slice 5 10 (V.fromList [1 .. 10::Double] V.++ V.replicate 10 7)
+
+w = linspace 5 (0,2)
+
+main = do
+    print $ fromVector v
+    print $ toVector w
diff --git a/hmatrix.cabal b/hmatrix.cabal
index b99c109..290515e 100644
--- a/hmatrix.cabal
+++ b/hmatrix.cabal
@@ -1,5 +1,5 @@
 Name:               hmatrix
-Version:            0.8.3.2
+Version:            0.8.4.0
 License:            GPL
 License-file:       LICENSE
 Author:             Alberto Ruiz
@@ -42,6 +42,7 @@ extra-source-files: examples/tests.hs
                     examples/devel/ej2/wrappers.hs
                     examples/devel/ej2/functions.c
                     examples/Real.hs
+                    examples/vector.hs
 
 extra-source-files: lib/Numeric/LinearAlgebra/LAPACK/lapack-aux.h,
                     lib/Numeric/LinearAlgebra/LAPACK/clapack.h
diff --git a/lib/Data/Packed/Development.hs b/lib/Data/Packed/Development.hs
index 56e7b8f..a9e6ac2 100644
--- a/lib/Data/Packed/Development.hs
+++ b/lib/Data/Packed/Development.hs
@@ -9,8 +9,7 @@
 -- Stability   :  provisional
 -- Portability :  portable
 --
--- The implementation of the 'Vector' and 'Matrix' types is not exposed,
--- but the library can be easily extended with additional foreign functions
+-- The library can be easily extended with additional foreign functions
 -- using the tools in this module. Illustrative usage examples can be found
 -- in the @examples\/devel@ folder included in the package.
 --
@@ -22,6 +21,8 @@ module Data.Packed.Development (
     vec, mat,
     app1, app2, app3, app4,
     MatrixOrder(..), orderOf, cmat, fmat,
+    unsafeFromForeignPtr,
+    unsafeToForeignPtr
 ) where
 
 import Data.Packed.Internal
diff --git a/lib/Data/Packed/Internal/Vector.hs b/lib/Data/Packed/Internal/Vector.hs
index 66acd87..51c0d92 100644
--- a/lib/Data/Packed/Internal/Vector.hs
+++ b/lib/Data/Packed/Internal/Vector.hs
@@ -23,7 +23,9 @@ module Data.Packed.Internal.Vector (
     createVector, withVector, vec,
     asComplex, asReal,
     fwriteVector, freadVector, fprintfVector, fscanfVector,
-    cloneVector
+    cloneVector,
+    unsafeToForeignPtr,
+    unsafeFromForeignPtr
 ) where
 
 import Data.Packed.Internal.Common
@@ -51,6 +53,14 @@ data Vector t =
       , fptr :: {-# UNPACK #-} !(ForeignPtr t)    -- ^ foreign pointer to the memory block
       }
 
+unsafeToForeignPtr :: Vector a -> (ForeignPtr a, Int, Int)
+unsafeToForeignPtr v = (fptr v, 0, idim v)
+
+-- | Same convention as in Roman Leshchinskiy's vector package.
+unsafeFromForeignPtr :: ForeignPtr a -> Int -> Int -> Vector a
+unsafeFromForeignPtr fp i n | i == 0 = V {idim = n, fptr = fp}
+                            | otherwise = error "unsafeFromForeignPtr with nonzero offset"
+
 -- | Number of elements
 dim :: Vector t -> Int
 dim = idim