diff --git a/CaseBi.hs b/CaseBi.hs --- a/CaseBi.hs +++ b/CaseBi.hs @@ -1,7 +1,7 @@ --{-# LANGUAGE BangPatterns #-} module CaseBi ( --- * Function that can be used instead of +-- * Function that can be used instead of 'case ... of' construction -- -- > case var of -- > a1 -> b1 @@ -11,9 +11,9 @@ -- > an -> bn -- > _ -> def -- --- for efficiency +-- for efficiency or other data representation getBFst', getBFst, getBFstV, --- * Additional functions that are used to sort a list of pairs (which can be obtained by e. g. Prelude.zip) +-- * Additional functions that are used to sort a list of pairs (which can be obtained e. g. by Prelude.zip) sortFst, sortFstV, -- ** Function that can be used for changing the Vector (a, b) during its creation filterP @@ -34,14 +34,16 @@ -- > an -> bn -- > _ -> defaultValue -- --- The function 'case a of ...' gives the /O(n)/ coplexity of the transformation of a to b here, --- but the function getBFst' tries to give about /O(log n)/ complexity --- The Vector (a, b) must be sorted in ascending order here for the algorithm to be used correctly. For this you can use +-- If we follow a lot of teaching materials that explain the workflow of the construction we think that the complexity of it is about /O(n)/ for the transformation of @a@ to @b@ here. +-- David Feuer (david.feuer@gmail.com) said that 'case ... of' is already optimized in GHC. Some benchmarks show that its behaviour tends to be about of /O(log n)/ complexity, the same as +-- the proposed function getBFst'. Nevertheless, the last one shows better performance in some situations, is rather general and can be used for another data representation. +-- Therefore, it can be preferred in some situations. getBFst' uses binary search algorithm and a Vector (a, b) as somewhat like a complicated filter or like a special sieve. +-- The @Vector (a, b)@ must be sorted in ascending order here for the algorithm to be used correctly. For this you can use -- the following functions 'sortFst' and 'sortFstV'. -- --- b before Vector (a, b) in the type definition of the 'getBFst' must be a @defaultValue@ for 'case' above. +-- @b@ before @Vector (a, b)@ in the tuple in the type definition of the 'getBFst' must be a @defaultValue@ for 'case' above. -- --- Vector (a, b) corresponds to +-- @Vector (a, b)@ corresponds to -- -- > a1 -> b1 -- > a2 -> b2 @@ -49,18 +51,18 @@ -- > ... -- > an -> bn -- -getBFst' :: (Ord a) => b -- ^ a default value that can be substituted if there is no correspendence in the set of (a, b) tuples (the 'otherwise' or irrefutable pattern analogue) - -> V.Vector (a, b) -- ^ Vector of the (a, b) tuples that must be sorted in ascending order for the first argument. If there are several pairs (a, b) with the same a, - -- ^ the function gives a resulting b as if there is only the first one +getBFst' :: (Ord a) => (b, V.Vector (a, b)) -- ^ a default value that can be substituted if there is no correspendence in the set of @(a, b)@ tuples (the 'otherwise' or irrefutable pattern analogue). + -- ^ Vector of the @(a, b)@ tuples that must be sorted in ascending order for the first argument. If there are several pairs (a, b) with the same @a@, + -- ^ the function gives a resulting @b@ as if there is only the first one -> a -- ^ an element for which the corresponding resulting b must be found -> b -- ^ the result -getBFst' def vec l | if (l < (fst (V.unsafeHead vec))) then True else (l > (fst (V.unsafeLast vec))) = def - | (V.length vec >= 2) = if l <= fst (vec V.! (V.length vec `quot` 2)) - then getBFst' def (V.unsafeSlice 0 (V.length vec `quot` 2) vec) l - else getBFst' def (V.unsafeSlice (V.length vec `quot` 2) (V.length vec - (V.length vec `quot` 2)) vec) l - | otherwise = snd (V.unsafeHead vec) +getBFst' (def, vec) l | if (l < (fst (V.unsafeHead vec))) then True else (l > (fst (V.unsafeLast vec))) = def + | (V.length vec >= 2) = if l <= fst (vec V.! (V.length vec `quot` 2)) + then getBFst' (def, (V.unsafeSlice 0 (V.length vec `quot` 2) vec)) l + else getBFst' (def, (V.unsafeSlice (V.length vec `quot` 2) (V.length vec - (V.length vec `quot` 2)) vec)) l + | otherwise = snd (V.unsafeHead vec) --- | The function that uses special kind of bisection to effectively transform the Vector a to Vector b with instead of simply use +-- | The function that uses special realization of the binary search to effectively transform the @Vector a@ to @Vector b@ instead of simply use -- -- > case var of -- > a1 -> b1 @@ -70,15 +72,12 @@ -- > an -> bn -- > _ -> defaultValue -- --- The function 'V.map (f (case var of ...)) [a]' gives the /O(n*m)/ coplexity of the transformation of Vector a to Vector b here --- where m is the length of the Vector a (and Vector b respectively here), but the function 'getBFstV' tries to give about /O(m*log n)/ complexity --- The Vector (a, b) must be sorted in ascending order here for the algorithm to be used correctly. For this you can use --- the following functions 'sortFst' and 'sortFstV'. If m >> n than the function gives more efficiency. Even otherwise, --- it can be used to simplify the procedure for optimizing the code for transformation of the Vector data. +-- The @Vector (a, b)@ must be sorted in ascending order here for the algorithm to be used correctly. For this you can use +-- the following functions 'sortFst' and 'sortFstV'. it can be used to simplify the procedure for optimizing the code for transformation of the Vector data. -- --- b after Vector (a, b) in the type definition of the 'getBFstV' must be a defaultValue for case above. +-- @b@ after @Vector (a, b)@ in the type definition of the 'getBFstV' must be a @defaultValue@ for 'case' above. -- --- Vector (a, b) corresponds to +-- @Vector (a, b)@ corresponds to -- -- > a1 -> b1 -- > a2 -> b2 @@ -86,13 +85,13 @@ -- > ... -- > an -> bn -- -getBFstV :: (Ord a) => V.Vector (a, b) -- ^ Vector of the (a, b) tuples that are sorted in ascending order for the first argument - -> b -- ^ a default value that can be substituted if there is no correspendence in the set of (a, b) tuples (the 'otherwise' or irrefutable pattern analogue) - -> V.Vector a -- ^ a Vector needed to be transformed accordingly to the correct (a, b) tuple pairs +getBFstV :: (Ord a) => V.Vector (a, b) -- ^ Vector of the @(a, b)@ tuples that are sorted in ascending order for the first argument + -> b -- ^ a default value that can be substituted if there is no correspendence in the set of @(a, b)@ tuples (the 'otherwise' or irrefutable pattern analogue) + -> V.Vector a -- ^ a Vector needed to be transformed accordingly to the correct @(a, b)@ tuple pairs -> V.Vector b -- ^ the resulting Vector -getBFstV c y = V.map (getBFst' y c) +getBFstV c y = V.map (getBFst' (y, c)) --- | The function that uses special kind of bisection to effectively transform the [a] to [b] with instead of simply use +-- | The function that uses special kind of bisection to effectively transform the @[a]@ to @[b]@ instead of simply use -- -- > case var of -- > a1 -> b1 @@ -102,15 +101,13 @@ -- > an -> bn -- > _ -> defaultValue -- --- The function 'map (f (case var of ...)) [a]' gives the /O(n*m)/ coplexity of the transformation of [a] to [b] here --- where m is the length of the [a] (and [b] respectively here), but the function 'getBFst' tries to give about /O(m*log n)/ complexity --- The Vector (a, b) must be sorted in ascending order here for the algorithm to be used correctly. For this you can use --- the following functions 'sortFst' and 'sortFstV'. If m >> n than the function gives more efficiency. Even otherwise, --- it can be used to simplify the procedure for optimizing the code for transformation of the list data. +-- The @Vector (a, b)@ must be sorted in ascending order here for the algorithm to be used correctly. For this you can use +-- the following functions 'sortFst' and 'sortFstV'. The function can be used to simplify the procedure for optimizing the code for transformation of the list data +-- or to represent the data in another way. -- --- b after Vector (a, b) in the type definition of the 'getBFst' must be a defaultValue for 'case' above. +-- @b@ after @Vector (a, b)@ in the type definition of the 'getBFst' must be a @defaultValue@ for 'case' above. -- --- Vector (a, b) corresponds to +-- @Vector (a, b)@ corresponds to -- -- > a1 -> b1 -- > a2 -> b2 @@ -118,20 +115,20 @@ -- > ... -- > an -> bn -- -getBFst :: (Ord a) => V.Vector (a, b) -- ^ Vector of the (a, b) tuples that must be sorted in ascending order for the first argument - -> b -- ^ a default value that can be substituted if there is no correspendence in the set of (a, b) tuples (the 'otherwise' or irrefutable pattern analogue) - -> [a] -- ^ a list of values needed to be transformed accordingly to the correct (a, b) tuple pairs +getBFst :: (Ord a) => V.Vector (a, b) -- ^ Vector of the @(a, b)@ tuples that must be sorted in ascending order for the first argument + -> b -- ^ a default value that can be substituted if there is no correspendence in the set of @(a, b)@ tuples (the 'otherwise' or irrefutable pattern analogue) + -> [a] -- ^ a list of values needed to be transformed accordingly to the correct @(a, b)@ tuple pairs -> [b] -- ^ the resulting list -getBFst c y = map (getBFst' y c) +getBFst c y = map (getBFst' (y, c)) --- | Function that sorts a list of (a, b) tuples by the first argument (@a@ must be an instance of class Ord) --- and is inspired by Data.List.sort function (the last one can be used for sorting the (a, b) tuples where both the types of a and b +-- | Function that sorts a list of @(a, b)@ tuples by the first argument +-- and is inspired by Data.List.sort function (the last one can be used for sorting the @(a, b)@ tuples where both the types of @a@ and @b@ -- have instances of the class Ord). It is inspired by the work: https://wiki.haskell.org/Introduction sortFst :: (Ord a) => [(a, b)] -> [(a, b)] sortFst xs | not . null $ xs = let z = fst . head $ xs in sortFst (filter (\(x, _) -> x < z) xs) ++ filter (\(x, _) -> x == z) xs ++ sortFst (filter (\(x, _) -> x > z) xs) | otherwise = [] --- | Function that prepares the list of (a, b) tuples representing the +-- | Function that prepares the list of @(a, b)@ tuples representing the -- -- > case var of -- > a1 -> b1 @@ -141,26 +138,24 @@ -- > an -> bn -- > _ -> defaultValue -- --- for usage in the 'getBFst' and 'getBFstV' functions. @a@ must be an instance of class Ord. +-- for usage in the 'getBFst' and 'getBFstV' functions. -- --- The resulting vector has for every @a@ only one element, which was the first in the list of tuples (a, b) after sorting by 'sortFst' function. +-- The resulting vector has for every @a@ only one element, which was the first in the list of tuples @(a, b)@ after sorting by 'sortFst' function. -- sortFstV :: (Ord a) => [(a, b)] -> V.Vector (a, b) sortFstV = V.fromList . L.nubBy (\x y -> fst x == fst y) . sortFst --- | The function that is used to filter a list [(a, b)] of the corresponding values for getFstB' to obtain the Vector (a, b) --- such that the b element for the sequence of pairs (a, b) with the same a is selected by the predicate p and is not necessarily the first one +-- | The function that is used to filter @[(a, b)]@ of the corresponding values for getFstB' to obtain the @Vector (a, b)@ +-- such that the @b@ element for the sequence of pairs @(a, b)@ with the same @a@ is selected by the predicate @p@ and is not necessarily the first one -- as it is for the getFstB' function and its successors by default. -filterP :: (Ord a) => ((a, b) -> Bool) -- ^ The predicate p used to select the only one value of b in the pairs (a, b) with the same a. - -- ^ If there are several pairs (a, b) for the same a that satisfies a predicate then the first one is used. For large [(a, b)] +filterP :: (Ord a) => ((a, b) -> Bool) -- ^ The predicate @p@ used to select the only one value of @b@ in the pairs @(a, b)@ with the same @a@. + -- ^ If there are several pairs @(a, b)@ for the same @a@ that satisfies a predicate then the first one is used. For large @[(a, b)]@ -- ^ it can be rather complex. - -> [(a, b)] -- ^ The list of (a, b) sorted in the ascending order by the first element a (e. g. by the 'sortFst' function) - -> V.Vector (a, b) -- ^ The resulting filtered Vector (a, b) that can be used for getFstB' and its successor functions + -> [(a, b)] -- ^ The list of @(a, b)@ sorted in the ascending order by the first element a (e. g. by the 'sortFst' function) + -> V.Vector (a, b) -- ^ The resulting filtered @Vector (a, b)@ that can be used for getFstB' and its successor functions. -- -- Example: -- -- > filterP (\(t, w) -> (t == "1") || (w > 'f')) . sortFst $ [("1",'a'),("4a",'k'),("4a",'b'),("4a",'c'),("4a",'d'),("4a",'e'),("b7",'c'),("b7",'k')] = [("1",'a'),("4a",'k'),("b7",'k')] -- filterP p xs = V.fromList . concatMap (\x -> take 1 . dropWhile (not . p) $ x) $ L.groupBy (\(x1,_) (x2,_) -> x1 == x2) xs - - diff --git a/ChangeLog.md b/ChangeLog.md --- a/ChangeLog.md +++ b/ChangeLog.md @@ -13,3 +13,9 @@ * First version revised C. Some performance improvements and changing the imported functions. +## 0.1.5.0 -- 2019-09-28 + +* First version revised D. Some performance improvements and changing the documentation. +The benchmark testing continues. + + diff --git a/mmsyn2.cabal b/mmsyn2.cabal --- a/mmsyn2.cabal +++ b/mmsyn2.cabal @@ -2,7 +2,7 @@ -- see http://haskell.org/cabal/users-guide/ name: mmsyn2 -version: 0.1.4.0 +version: 0.1.5.0 synopsis: The library that can be used for multiple (Ord a) => a -> b transformations description: The library that can be used for optimization or another representation of multiple (Ord a) => a -> b transformations homepage: https://oleksandrzhabenko.github.io/mmsyn2