Xawirses/GitMining
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

implemented phase 2

Browse Source
This commit is contained in:
IGI-111
2015-04-05 17:55:16 +02:00
parent 32309510a8
commit c108e32c89
5 changed files with 83 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

28
FrequentPatterns.hs
View File

@@ -7,9 +7,12 @@ import Debug.Trace (traceShow)
import qualified Data.List as List
semiUnion :: ItemSet -> ItemSet -> ItemSet
semiUnion (ItemSet set1) (ItemSet set2) = ItemSet (if max1 <= max2 && Set.delete max1 set1 == Set.delete max2 set2 then set1 `Set.union` set2 else Set.empty) where
max1 = Set.findMax set1
max2 = Set.findMax set2
semiUnion (ItemSet set1) (ItemSet set2) = ItemSet $
if max1 <= max2 && Set.delete max1 set1 == Set.delete max2 set2
then set1 `Set.union` set2
else Set.empty where
max1 = Set.findMax set1
max2 = Set.findMax set2
-- generate all possible combinations from a set of singletons
-- generateLevels :: [Item] -> [[ItemSet]]
@@ -19,15 +22,18 @@ semiUnion (ItemSet set1) (ItemSet set2) = ItemSet (if max1 <= max2 && Set.delete
-- generate the next level in a bottom-up route
generateNextLevel :: [ItemSet] -> [ItemSet]
generateNextLevel level = traceShow ("Computing level " ++ show (isSize (head level))) $ foldr (\value old -> generate value ++ old) [] level where
generate value = takeWhile (/= empty) (foldr (\x old -> semiUnion value x : old) [] (tail $ List.dropWhile (/= value) level))
empty = ItemSet $ Set.fromList []
isSize (ItemSet set) = Set.size set
generateNextLevel level = traceShow ("Computing level " ++ show (isSize (head level))) $
foldr (\value old -> generate value ++ old) [] level where
generate value = takeWhile (/= empty)
(foldr (\x old -> semiUnion value x : old) [] (tail $ List.dropWhile (/= value) level))
isSize (ItemSet set) = Set.size set
singletons :: [ItemSet] -> [Item]
singletons table = Set.toList $ foldr (\(ItemSet row) old -> old `Set.union` row) (Set.fromList []) table where
singletons table = Set.toList $ foldr union (Set.fromList []) table where
union (ItemSet row) old = old `Set.union` row
frequentPatterns :: Frequency -> [ItemSet] -> [[ItemSet]]
frequentPatterns thresh table = until (\x -> [] == head x) (\x -> filterByFrequency (generateNextLevel (head x)) : x) [firstLevel] where
firstLevel = filterByFrequency $ map (\x -> ItemSet $ Set.fromList [x]) (singletons table)
filterByFrequency = filter (\x -> frequency table x >= thresh)
frequentPatterns thresh table = until (\x -> [] == head x)
(\x -> filterByFrequency (generateNextLevel (head x)) : x) [firstLevel] where
firstLevel = filterByFrequency $ map (\x -> ItemSet $ Set.fromList [x]) (singletons table)
filterByFrequency = filter (\x -> frequency table x >= thresh)