Bulat,
The strictness gave me something like a 10% performance increase
making the Haskell code more than 10 times slower than the C. Is this
the right type of array to use for performance?
--
Dan
On Nov 8, 2007 10:36 AM, Bulat Ziganshin <[EMAIL PROTECTED]> wrote:
> 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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