Control.Concurrent.Speculation.List

Speculative scans

scan :: (Monoid m, Eq m) => (Int -> m) -> [m] -> [m]

Given a valid estimator g, scan g xs converts xs into a list of the prefix sums.

g n should supply an estimate of the value of the monoidal summation over the first n elements of the container.

If g n is accurate a reasonable percentage of the time and faster to compute than the prefix sum, then this can provide increased opportunities for parallelism.

scanBy :: Monoid m => (m -> m -> Bool) -> (Int -> m) -> [m] -> [m]

scan using specBy

scanMap :: (Monoid m, Eq m) => (Int -> m) -> (a -> m) -> [a] -> [m]

Given a valid estimator g, scanMap g f xs converts xs into a list of the prefix sums.

g n should supply an estimate of the value of the monoidal summation over the first n elements of the container.

If g n is accurate a reasonable percentage of the time and faster to compute than the scan, then this can provide increased opportunities for parallelism.

 scan = scanMap id
 scanMap = scanMapBy (==)

scanMapBy :: Monoid m => (m -> m -> Bool) -> (Int -> m) -> (a -> m) -> [a] -> [m]

scanr :: Eq b => (Int -> b) -> (a -> b -> b) -> b -> [a] -> [b]

Given a valid estimator g, scanr g f z xs yields the same answer as scanr' f z xs.

g n should supply an estimate of the value returned from scanning over the last n elements of the container.

If g n is accurate a reasonable percentage of the time and faster to compute than the scan, then this can provide increased opportunities for parallelism.

scanrBy :: (b -> b -> Bool) -> (Int -> b) -> (a -> b -> b) -> b -> [a] -> [b]

scanl :: Eq b => (Int -> b) -> (b -> a -> b) -> b -> [a] -> [b]

scanlBy :: (b -> b -> Bool) -> (Int -> b) -> (b -> a -> b) -> b -> [a] -> [b]

scanr1 :: Eq a => (Int -> a) -> (a -> a -> a) -> [a] -> [a]

scanr1By :: (a -> a -> Bool) -> (Int -> a) -> (a -> a -> a) -> [a] -> [a]

scanl1 :: Eq a => (Int -> a) -> (a -> a -> a) -> [a] -> [a]

scanl1By :: (a -> a -> Bool) -> (Int -> a) -> (a -> a -> a) -> [a] -> [a]