so i have a function that is eating *tons* of memory. my application is clustering and i put everything in UArrays or Arrays. for clustering 5 data points with 4 features (a tiny tiny set) the program gobbles 350mbs! most of the usage is coming from this distance function: dist dat Nothing pq@(p,q) = (uncurry loop) (bounds xp) 0 (\a i -> a + (sqr (xp!i - xq!i))) where Vector xp = dat !!! p Vector xq = dat !!! q dist dat (Just (Vector w)) pq@(p,q) = (uncurry loop) (bounds xp) 0 (\a i -> a + ((sqr (w!i)) * (sqr (xp!i - xq!i)))) where Vector xp = dat !!! p Vector xq = dat !!! q Where the relevant definitions are: type Vector = Vector (UArray Int Double) (!!!) = Array.(!) and loop is: loop :: (Num i, Ord i, Ix i) => i -> i -> a -> (a -> i -> a) -> a loop low high a f = loop' a low where loop' a pos | pos > high = a | otherwise = loop' (f a pos) (pos+1) i cannot figure out why such a function would be eating so much memory. i even tried changing the function provided to loop with "a `seq` ..." to make sure we're not creating a huge thunk, but that didn't help at all. but, according to my profiling: dist Main 380000 27.7 23.6 64.9 61.0 sqr Main 2280000 1.6 7.9 1.6 7.9 !!! Main 760000 4.7 0.0 4.7 0.0 loop Loops 380000 30.8 29.5 30.8 29.5 i realize it's being entered a lot of times, and i can understand that it would use a bunch of time resources, but i don't understand why it's using so much space. any help would be appreciated... - Hal -- Hal Daume III "Computer science is no more about computers | hdaume@isi.edu than astronomy is about telescopes." -Dijkstra | www.isi.edu/~hdaume