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|
{-# OPTIONS_GHC -fglasgow-exts -fallow-undecidable-instances #-}
-----------------------------------------------------------------------------
-- |
-- Module : Data.Packed.Internal.Vector
-- Copyright : (c) Alberto Ruiz 2007
-- License : GPL-style
--
-- Maintainer : Alberto Ruiz <aruiz@um.es>
-- Stability : provisional
-- Portability : portable (uses FFI)
--
-- Vector implementation
--
-----------------------------------------------------------------------------
-- #hide
module Data.Packed.Internal.Vector where
import Data.Packed.Internal.Common
import Foreign
import Complex
import Control.Monad(when)
-- | A one-dimensional array of objects stored in a contiguous memory block.
data Vector t = V { dim :: Int -- ^ number of elements
, fptr :: ForeignPtr t -- ^ foreign pointer to the memory block
}
--ptr (V _ fptr) = unsafeForeignPtrToPtr fptr
-- | signature of foreign functions admitting C-style vectors
type Vc t s = Int -> Ptr t -> s
-- not yet admitted by my haddock version
-- infixr 5 :>
-- type t :> s = Vc t s
vec = withVector
withVector (V n fp) f = withForeignPtr fp $ \p -> do
let v g = do
g n p
f v
-- | allocates memory for a new vector
createVector :: Storable a => Int -> IO (Vector a)
createVector n = do
when (n <= 0) $ error ("trying to createVector of dim "++show n)
fp <- mallocForeignPtrArray n
return $ V n fp
{- | creates a Vector from a list:
@> fromList [2,3,5,7]
4 |> [2.0,3.0,5.0,7.0]@
-}
fromList :: Storable a => [a] -> Vector a
fromList l = unsafePerformIO $ do
v <- createVector (length l)
let f _ p = pokeArray p l >> return 0
app1 f vec v "fromList"
return v
safeRead v = unsafePerformIO . withForeignPtr (fptr v)
{- | extracts the Vector elements to a list
@> toList (linspace 5 (1,10))
[1.0,3.25,5.5,7.75,10.0]@
-}
toList :: Storable a => Vector a -> [a]
toList v = safeRead v $ peekArray (dim v)
-- | an alternative to 'fromList' with explicit dimension, used also in the instances for Show (Vector a).
(|>) :: (Storable a) => Int -> [a] -> Vector a
infixl 9 |>
n |> l = if length l == n then fromList l else error "|> with wrong size"
-- | access to Vector elements without range checking
at' :: Storable a => Vector a -> Int -> a
at' v n = safeRead v $ flip peekElemOff n
-- | access to Vector elements with range checking.
at :: Storable a => Vector a -> Int -> a
at v n | n >= 0 && n < dim v = at' v n
| otherwise = error "vector index out of range"
{- | takes a number of consecutive elements from a Vector
@> subVector 2 3 (fromList [1..10])
3 |> [3.0,4.0,5.0]@
-}
subVector :: Storable t => Int -- ^ index of the starting element
-> Int -- ^ number of elements to extract
-> Vector t -- ^ source
-> Vector t -- ^ result
subVector k l (v@V {dim=n})
| k<0 || k >= n || k+l > n || l < 0 = error "subVector out of range"
| otherwise = unsafePerformIO $ do
r <- createVector l
let f _ s _ d = copyArray d (advancePtr s k) l >> return 0
app2 f vec v vec r "subVector"
return r
{- | Reads a vector position:
@> fromList [0..9] \@\> 7
7.0@
-}
(@>) :: Storable t => Vector t -> Int -> t
infixl 9 @>
(@>) = at
{- | creates a new Vector by joining a list of Vectors
@> join [fromList [1..5], constant 1 3]
8 |> [1.0,2.0,3.0,4.0,5.0,1.0,1.0,1.0]@
-}
join :: Storable t => [Vector t] -> Vector t
join [] = error "joining zero vectors"
join as = unsafePerformIO $ do
let tot = sum (map dim as)
r@V {fptr = p} <- createVector tot
withForeignPtr p $ \ptr ->
joiner as tot ptr
return r
where joiner [] _ _ = return ()
joiner (V {dim = n, fptr = b} : cs) _ p = do
withForeignPtr b $ \pb -> copyArray p pb n
joiner cs 0 (advancePtr p n)
-- | transforms a complex vector into a real vector with alternating real and imaginary parts
asReal :: Vector (Complex Double) -> Vector Double
asReal v = V { dim = 2*dim v, fptr = castForeignPtr (fptr v) }
-- | transforms a real vector into a complex vector with alternating real and imaginary parts
asComplex :: Vector Double -> Vector (Complex Double)
asComplex v = V { dim = dim v `div` 2, fptr = castForeignPtr (fptr v) }
----------------------------------------------------------------
-- | map on Vectors
liftVector :: (Storable a, Storable b) => (a-> b) -> Vector a -> Vector b
liftVector f = fromList . map f . toList
-- | zipWith for Vectors
liftVector2 :: (Storable a, Storable b, Storable c) => (a-> b -> c) -> Vector a -> Vector b -> Vector c
liftVector2 f u v = fromList $ zipWith f (toList u) (toList v)
-----------------------------------------------------------------
|
