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{-# LANGUAGE ForeignFunctionInterface #-}
-----------------------------------------------------------------------------
{- |
Module : Numeric.GSL.Fourier
Copyright : (c) Alberto Ruiz 2006
License : GPL-style
Maintainer : Alberto Ruiz (aruiz at um dot es)
Stability : provisional
Portability : uses ffi
Fourier Transform.
<http://www.gnu.org/software/gsl/manual/html_node/Fast-Fourier-Transforms.html#Fast-Fourier-Transforms>
-}
-----------------------------------------------------------------------------
module Numeric.GSL.Fourier (
fft,
ifft
) where
import Data.Packed.Internal
import Data.Complex
import Foreign.C.Types(CInt(..))
import System.IO.Unsafe (unsafePerformIO)
genfft code v = unsafePerformIO $ do
r <- createVector (dim v)
app2 (c_fft code) vec v vec r "fft"
return r
foreign import ccall "gsl-aux.h fft" c_fft :: CInt -> TCVCV
{- | Fast 1D Fourier transform of a 'Vector' @(@'Complex' 'Double'@)@ using /gsl_fft_complex_forward/. It uses the same scaling conventions as GNU Octave.
@> fft ('fromList' [1,2,3,4])
vector (4) [10.0 :+ 0.0,(-2.0) :+ 2.0,(-2.0) :+ 0.0,(-2.0) :+ (-2.0)]@
-}
fft :: Vector (Complex Double) -> Vector (Complex Double)
fft = genfft 0
-- | The inverse of 'fft', using /gsl_fft_complex_inverse/.
ifft :: Vector (Complex Double) -> Vector (Complex Double)
ifft = genfft 1
|
