1 files changed, 2 insertions, 2 deletions

diff --git a/lib/Data/Packed/Internal/Vector.hs b/lib/Data/Packed/Internal/Vector.hs
index 6d39c6e..dfa2e86 100644
--- a/lib/Data/Packed/Internal/Vector.hs
+++ b/lib/Data/Packed/Internal/Vector.hs
@@ -266,13 +266,13 @@ takesV ms w | sum ms > dim w = error $ "takesV " ++ show ms ++ " on dim = " ++ (
 ---------------------------------------------------------------
 
 -- | transforms a complex vector into a real vector with alternating real and imaginary parts 
-asReal :: Vector (Complex a) -> Vector a
+asReal :: (RealFloat a, Storable a) => Vector (Complex a) -> Vector a
 --asReal v = V { ioff = 2*ioff v, idim = 2*dim v, fptr =  castForeignPtr (fptr v) }
 asReal v = unsafeFromForeignPtr (castForeignPtr fp) (2*i) (2*n)
     where (fp,i,n) = unsafeToForeignPtr v
 
 -- | transforms a real vector into a complex vector with alternating real and imaginary parts
-asComplex :: Vector a -> Vector (Complex a)
+asComplex :: (RealFloat a, Storable a) => Vector a -> Vector (Complex a)
 --asComplex v = V { ioff = ioff v `div` 2, idim = dim v `div` 2, fptr =  castForeignPtr (fptr v) }
 asComplex v = unsafeFromForeignPtr (castForeignPtr fp) (i `div` 2) (n `div` 2)
     where (fp,i,n) = unsafeToForeignPtr v