DistanceTransform.Internal.Indexer

Helpers for performing nested loop iteration. Includes variants for parallel computation.

Documentation

data Zipper a

We use a zipper on list to walk over dimensions of an array.

Constructors

Zip [a] a [a]

toZipper :: a -> [a] -> Zipper a

Create a Zipper from a non-empty list, with the cursor on the leftmost element.

unsafeToZipper :: [a] -> Zipper a

Create a Zipper from a non-empty list, with the cursor on the leftmost element. An exception is thrown if the given list is empty.

fromZipper :: Zipper a -> [a]

Convert a Zipper to a list.

left :: Zipper a -> Maybe (Zipper a)

Move a Zipper to the left.

unsafeLeft :: Zipper a -> Zipper a

right :: Zipper a -> Maybe (Zipper a)

focus :: Zipper a -> a

Comonadic coreturn: produce the value a Zipper is currently focused upon.

rightmost :: Zipper a -> Zipper a

Slide a Zipper over until focused on its rightmost element.

zipSum :: Num a => Zipper a -> a

Since we are using Zippers to track the size of multidemensional arrays, the sum of all zipper elements gives the size of the entire array.

zipStep :: Num a => Zipper a -> a

Computes the step between consective elements at the currently focused dimension. This involves stepping over all nested dimensions.

zipStride :: Num a => Zipper a -> a

Computes the stride between rows at the currently focused dimension. This involves stepping over the rest of the current row along all nested dimensions.

zipFoldM :: Monad m => Zipper Int -> (a -> Int -> m a) -> a -> [Int] -> m ()

parChunkMapM_ :: (a -> IO ()) -> [a] -> IO ()

parZipFoldM :: Zipper Int -> (a -> Int -> IO a) -> a -> [Int] -> IO ()

zipMapM_ :: Monad m => Zipper Int -> (Int -> m ()) -> [Int] -> m ()

zipFoldMAsYouDo :: Monad m => Zipper Int -> (Int -> Int -> m ()) -> m ()

parZipFoldMAsYouDo :: Zipper Int -> (Int -> Int -> IO ()) -> IO ()