Ahn, Ki Yung wrote:
Recently, I'm facing the dark side of laziness -- the memory leak because of laziness.
The following is the code that leaks memory.
sctAnal gs = null cgs || all (not . null) dcs where gs' = fixSize compose $ Set.fromList [TT (x,y,cs) [] | To _ x y cs<-Set.toList gs] cgs = [z | z@(TT (x,y,cs) _)<-Set.toList gs', x==y] dcs = [[c| c@(a,D,b)<-Set.toList cs , a==b] | TT (_,_,cs) _<-cgs] compose gs = trace ("## "++show (Set.size gs)) $ foldr checkInsert
One thing is that (foldr) is not recommended if you can at all avoid it. I think you may be able to use (foldl') here (if you also swap the arg order for checkInsert) which behaves as a strict fold operation so it doesn't waste space building up thunks.
gs $ do TT (x1,y1,cs1) l1 <- Set.toList gs TT (_,y2,cs2) l2 <- takeWhileTTfrom y1 . Set.toList $ setGT (TT (y1,Al""(-1),Set.empty) []) gs return $ TT (x1,y2,cs1 `comp` cs2) (l1++y1:l2) takeWhileTTfrom y = takeWhile (\(TT (y',_,_) _) -> y==y') checkInsert x s
-- checkInsert s x -- if you use foldl'
| Set.member x s = s | otherwise = Set.insert x s
Sorry I can't help more at the moment - Regards, Brian. -- Logic empowers us and Love gives us purpose. Yet still phantoms restless for eras long past, congealed in the present in unthought forms, strive mightily unseen to destroy us. http://www.metamilk.com