DynamicTimeWarpingWin.hs

DynamicTimeWarpingWin.hs

dtwWin :: V.Vector a -> V.Vector a -> (a -> a -> Int) -> Int -> Array (Int,Int) Int
dtwWin x y cost window = runSTArray $ do
  let n = V.length x
      m = V.length y
      maxCost = maxBound
      w = max window (abs (n - m)) -- constrain window size
  d <- newArray ((0,0),(m,n)) maxCost
  writeArray d (0,0) 0
  forM_ [1..n] $ \i ->
    forM_ [max 1 (i-w) .. min m (i+w)] $ \j -> do
      let c = cost (x ! (i - 1)) (y ! (j - 1))
      insertion <- readArray d (j,i-1)
      deletion <- readArray d (j-1,i)
      match <- readArray d (j-1,i-1)
      writeArray d (j,i) (c + minimum [insertion,deletion,match])
  return d