[Haskell-beginners] Haskell code optimisation

[Dimitri DeFigueiredo]

with 'ghc -O2' this takes 14 seconds on my macbook pro.

Dimitri

On 12/12/15 10:35 AM, Abhishek Kumar wrote:
> Compiling below code (ghc --make) still doesn't gives result on my i3 
> Ubuntu 64bit machine.Can u please elaborate optimisations you did?
> Thanks
> Abhishek
>
> On Friday, December 11, 2015, Kim-Ee Yeoh <ky3 at atamo.com 
> <mailto:ky3 at atamo.com>> wrote:
>
>     Have you tried BangPatterns? Compiled with optimization, I get 22
>     secs. Here's the full program:
>
>     {-# LANGUAGE BangPatterns #-}
>
>     f :: Int -> Int -> Int
>     f !m !n
>        | m==0      = n+1
>        | n==0      = f (m-1) 1
>        | otherwise = f (m-1) (f m (n-1))
>
>     main = putStrLn (show (f 4 1))
>
>
>     -- Kim-Ee
>
>     On Fri, Dec 11, 2015 at 9:47 PM, Abhishek Kumar
>     <abhishekkmr18 at gmail.com
>     <javascript:_e(%7B%7D,'cvml','abhishekkmr18 at gmail.com');>> wrote:
>
>         I was trying to write below program for ackerman function but
>         it fails (waits too long) for ack(4,1) whereas a recursive C
>         program gives result in 37secs.Can someone pls explain this
>         behaviour and recomend some optimisation.
>
>         ------haskell code
>         f m n  | m==0 =n+1
>                    | n==0 = f  (m-1) 1
>                    | otherwise = f (m-1) (f m (n-1))
>
>         Thanks
>         Abhishek Kumar
>
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>
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