[Fwd: Re: [clean-list] Clean versus Haskell]
Adrian Hey
ahey at iee.org
Thu Oct 15 08:32:34 MEST 2009
-------- Original Message --------
Subject: Re: [clean-list] Clean versus Haskell
Date: Thu, 15 Oct 2009 06:41:20 +0100
From: Adrian Hey <ahey at iee.org>
To: Philippos Apolinarius <phi500ac at yahoo.ca>
References: <8400.82204.qm at web58803.mail.re1.yahoo.com>
Hello Philippos,
GHC has a long standing performance bug for garbage collection and
mutable arrays:
http://hackage.haskell.org/trac/ghc/ticket/650
For some reason they haven't (can't?) fixed it. I guess the
authors of Haskell/ghc shootout entries are aware of this so don't
use native mutable arrays in their entries (at least not those that
show haskell/ghc to be "fast" :-)
Regards
--
Adrian Hey
Philippos Apolinarius wrote:
> I wrote a very simple program to check whether Haskell improved its array processing libraries or not. Here is how to compile and run the program arr.hs in Haskell (I have used the GHC compiler):
>
>> ghc -O arr.hs -o arr.exe
>
> $ time arr.exe +RTS -K32000000
> 2.8e8
>
> real 0m3.938s
> user 0m0.031s
> sys 0m0.000s
>
> The same program in Clean:
> C:\Clean 2.2\exemplos\console>arraytest.exe
> 280000000
> Execution: 0.01 Garbage collection: 0.01 Total: 0.03
>
> C:\Clean 2.2\exemplos\console>arraytest.exe
> 280000000
> Execution: 0.01 Garbage collection: 0.01 Total: 0.03
>
> This means that Clean is 390 times faster than Haskell in this particular problem. These results makes me worder whether Haskell is safer than Clean. It turns out that Haskell checks index out of range at runtime, exactly like Clean. Larger problems make the difference between Clean and Haskell even worse. For instance, neural networks like the one described in Schmidtt et al. run 400 times faster in Clean.
>
> Haskell seems to be slow, and not safe. For instance, GHC compiler does not at a program trying to write into a closed handle.
>
> module Main where
> import System( getArgs )
> import IO
>
> main = do
> args <- getArgs
> if (length args /= 2)
> then putStr "Usage: f1a f2a <n>"
> else (do
> fromHandle <- openFile (head args) ReadMode
> contents <- hGetContents fromHandle
> toHandle <- openFile (head (tail args)) WriteMode
> hClose toHandle -- Comment this line
> hPutStr toHandle contents
> hClose toHandle
> putStr "Done.")
>
> The Clean equivalent program is somewhat smaller. In my opinion it is easier to understand. What is more important, Clean compiler balks at closed handles.
>
> module cleancopy
> import StdEnv, ArgEnv
>
> Start w
> # argv= getCommandLine
> | size argv < 3 = abort "Usage, etc."
> # (ok, f, w)= fopen argv.[1] FReadText w
> (contents, f)= freads f 64000
> (ok, f, w)= fopen argv.[2] FWriteText w
> f= fwrites contents f
> = fclose f w
>
> Below you will find the array examples. You can check that Clean is really much faster than Haskell. I wonder why the Benchmarks Game site does not report such a large difference between Haskell and Clean performances. I believe that people who wrote Haskell benchmarks for the Benchmarks Game site cheated in using foreign pointers to access arrays.
>
> -- arr.hs
> import Control.Monad.ST
> import Data.Array.ST
> main = print $ runST
> (do arr <- newArray (1,2000000)
> 137.0 :: ST s
> (STArray s
> Int Double)
> a <- readArray arr 1
> b <- readArray arr 1
> fn 2000000 arr 0.0 )
>
>
> fn i a acc | i < 1 = do (return acc)
> fn i a acc= do
> b <- readArray a i
> writeArray a i (b+3.0)
> c <- readArray a i
> fn (i-1) a (acc+c)
>
> //Clean version
> module arraytest
> import StdEnv
> fn i a acc | i<1 = acc
> fn i a=:{[i]=b} acc
> # a= {a&[i]= b+3.0}
> # (c, a)= a![i]
> = fn (i-1) a (c+acc)
>
> Start= fn 2000000 vt 0.0
> where
> vt:: .{#Real}
> vt = createArray 2000001 137.0
>
>
>
> --- On Mon, 10/12/09, rinus plasmeijer <rinus at cs.ru.nl> wrote:
>
> From: rinus plasmeijer <rinus at cs.ru.nl>
> Subject: [clean-list] Re: Clean
> To: "Henrique" <henrique_gusmao_ at hotmail.com>
> Cc: clean-list at science.ru.nl
> Received: Monday, October 12, 2009, 1:22 AM
>
>
>
>
>
>
>
> Hi Henrique
>
>
>> Is this e-mail still working? http://clean.cs.ru.nl/
>
>
> Yes.
>
>
>> I want to know more about Clean: news?
> updates?
>> What is the future of Clean?
>
> See: http://wiki.clean.cs.ru.nl/Latest_developments
> We are working on a new version which allows you to
> mix Clean and Haskell 98 code.
> It is a lot of work, it will still take some time.
>
>> Is Haskell killing Clean?
> Haskell is certainly much more used, which is also
> the raison for adding a Haskell front end.
>
>> I would like to
> learn and test Clean, and maybe then use it commercially.
>> Where do I
> can download it? I send e-mail to clean at cs.ru.nl , asked for
> Clean at the site above, but I got no answer.
>
> We did not got your
> email.
> To download browse to: http://clean.cs.ru.nl/Download/main/main.htm
>
>> Obs: I am using windows platform.
> Thats fine, it should work on any windows platform.
>
>
> Greetings,
>
> Rinus
>
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