Hello Dan,
Thursday, November 8, 2007, 9:33:12 PM, you wrote:
> main = do
> a <- newArray (0,n-1) 1.0 :: IO (IOUArray Int Double)
> forM_ [0..n-2] $ \i -> do { x <- readArray a i; y <- readArray a
> (i+1); writeArray a (i+1) (x+y) }
> x <- readArray a (n-1)
> print x
1. ghc doesn't implement loop unrolling, even in -O2 mode
2. forM_ may have its own overheads, i'm not sure
3. add strictness annotations:
forM_ [0..n-2] $ \i -> do { return $! i;
x <- readArray a i; return $! x;
y <- readArray a (i+1); return $! y;
writeArray a (i+1) (x+y) }
such cycle should be approx. 3-10 times slower than C one
--
Best regards,
Bulat mailto:[EMAIL PROTECTED]
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