On Feb 2, 2008 12:11 PM, Chaddaï Fouché <[EMAIL PROTECTED]> wrote:
> To address this I propose this function :
> foldl1MArray' :: (MArray a e m, Ix i) => (e -> e -> e) -> a i e -> m e
> foldl1MArray' f a = do
> (l,u) <- getBounds a
> firstElem <- readArray a l
> foldM (\a mb -> a `seq` mb >>= return . f a)
> firstElem (map (readArray a) (range (l,u)))
>
I played with your foldl1MArray' last night. I noticed it can be reduced to
. . .
foldl1MArray' :: (MArray a e m, Ix i) => (e -> e -> e) -> a i e -> m e
foldl1MArray' f a = do
(l,u) <- getBounds a
foldl1' (liftM2 f) (map (readArray a) (range (l,u)))
Unfortunately, my new version consumes a lot of stack and heap space. Why
is this so inefficient? Is there a simple change that will make it
efficient?
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