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Today's Topics:
1. Re: Working out the types (Patrick LeBoutillier)
2. I get no speedup with RWH examples of parallel sorting
(Kees Bleijenberg)
3. Re: I get no speedup with RWH examples of parallel sorting
(David Place)
4. Does one need a ticket to attend ICFP? (Sebastien Zany)
5. Throughly confused by this error message (Michael Litchard)
6. Re: Does one need a ticket to attend ICFP? (Erik de Castro Lopo)
7. Re: Throughly confused by this error message (Michael Litchard)
----------------------------------------------------------------------
Message: 1
Date: Wed, 6 Jul 2011 08:19:44 -0400
From: Patrick LeBoutillier <[email protected]>
Subject: Re: [Haskell-beginners] Working out the types
To: Daniel Fischer <[email protected]>
Cc: [email protected]
Message-ID:
<CAJcQsbiin4WPvaDjvN-Fi1uuAA9pXAyzKpay7_nKR4=0jbc...@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Daniel,
The paper you recommend seems like very interesting stuff. I will
definitely look at it closer.
Thanks a lot,
Patrick
On Tue, Jul 5, 2011 at 3:24 PM, Daniel Fischer
<[email protected]> wrote:
> On Tuesday 05 July 2011, 19:55:43, Patrick LeBoutillier wrote:
>> Hi all,
>
>> Here's my question: Does ghci have a verbose mode or something where
>> is can show you step by step how the types
>> are worked out?
>
> No. You can use it to get the types of subexpressions, though, and work
> towards the complete expression from that:
>
> Prelude> :t (:)
> (:) :: a -> [a] -> [a]
> Prelude> :t (. (:))
> (. (:)) :: (([a] -> [a]) -> c) -> a -> c
> Prelude> :t (map . (:))
> (map . (:)) :: a -> [[a]] -> [[a]]
>
> which gives you smaller gaps to fill in.
>
>> If not is there a hackage (or any other kind of)
>> package that can do that?
>
> I'm not aware of any, but there might be.
>
>>
>> a lot, so I was wondering if such a program existed that could do it
>> automatically.
>
> Automatic type checkers do exist (every compiler/interpreter needs one),
> but I don't think they have been written with the ability to output not
> only the result but also the derivation.
>
> For someone familiar with a particular type checker, it probably wouldn't
> be hard to add that feature, but if it's a complicated beast like GHC's
> type checker, becoming familiar with it would probably be a big
> undertaking.
>
> Writing your own much-reduced (able to parse and typecheck only a very
> restricted subset of the language) might be easier, but probably working
> from Mark P. Jones' "Typing Haskell in Haskell"
> http://web.cecs.pdx.edu/~mpj/thih/
> would be better than starting from scratch (it's somewhat oldish, so it
> certainly doesn't cope with recent GHC extensions, but for everyday run-of-
> the-mill problems, it should be working with only minor modifications).
>
>
--
=====================
Patrick LeBoutillier
Rosem?re, Qu?bec, Canada
------------------------------
Message: 2
Date: Wed, 6 Jul 2011 17:08:41 +0200
From: "Kees Bleijenberg" <[email protected]>
Subject: [Haskell-beginners] I get no speedup with RWH examples of
parallel sorting
To: <[email protected]>
Message-ID: <[email protected]>
Content-Type: text/plain; charset="us-ascii"
I've carefully followed the instructions in Real World Haskell for parallel
sorting:
In SortMain.hs
1. Set testfunction=sort
Then del *.o (force recompilation)
ghc --make -O2 sortMain.hs
run SortMain and I get 500000 numbers => 3.9735 sec.
2. Set testFunction = parSort2 2
del *.o
ghc -threaded --make -O2 sortMain.hs
run SortMain +RTS -N2 -RTS, I get => 5.3 sec
run SortMain +RTS -N1 -RTS, I get => 4.3 sec
With the +RTS -s option I get 3 SPARK3 (3 converted, 0 pruned)
All other testFunctions are worse.
I have a dual core computer that runs Windows XP.
I've experimented a lot with par, pseq ... in other programs. I almost
always get a few hundred sparks. Half of them are converted and the other
half gets pruned. But I never got a faster program (then sequential).
What am I doing wrong, any ideas?
Kees
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Message: 3
Date: Wed, 6 Jul 2011 11:43:27 -0400
From: David Place <[email protected]>
Subject: Re: [Haskell-beginners] I get no speedup with RWH examples of
parallel sorting
To: "Kees Bleijenberg" <[email protected]>
Cc: [email protected]
Message-ID: <[email protected]>
Content-Type: text/plain; charset="us-ascii"
My experience with running parallel programs on dual processor machines is
similar. With only two processors, one is always busy doing something for the
OS. As a result, it rarely gets scheduled. You need a quad cpu to play with
parallel programming.
____________________
David Place
Owner, Panpipes Ho! LLC
http://panpipesho.com
[email protected]
On Jul 6, 2011, at 11:08 AM, Kees Bleijenberg wrote:
> I've carefully followed the instructions in Real World Haskell for parallel
> sorting:
> In SortMain.hs
> 1. Set testfunction=sort
> Then del *.o (force recompilation)
> ghc --make -O2 sortMain.hs
> run SortMain and I get 500000 numbers => 3.9735 sec.
>
> 2. Set testFunction = parSort2 2
> del *.o
> ghc -threaded --make -O2 sortMain.hs
> run SortMain +RTS -N2 -RTS, I get => 5.3 sec
> run SortMain +RTS -N1 -RTS, I get => 4.3 sec
> With the +RTS -s option I get 3 SPARK3 (3 converted, 0 pruned)
> All other testFunctions are worse.
>
> I have a dual core computer that runs Windows XP.
> I've experimented a lot with par, pseq ... in other programs. I almost always
> get a few hundred sparks. Half of them are converted and the other half gets
> pruned. But I never got a faster program (then sequential).
>
> What am I doing wrong, any ideas?
>
> Kees
>
>
> _______________________________________________
> Beginners mailing list
> [email protected]
> http://www.haskell.org/mailman/listinfo/beginners
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Message: 4
Date: Wed, 6 Jul 2011 13:13:42 -0700
From: Sebastien Zany <[email protected]>
Subject: [Haskell-beginners] Does one need a ticket to attend ICFP?
To: Haskell Beginners <[email protected]>
Message-ID:
<caa+2x_vakwsf162zfsl1hq4wcbuz4pgqm8mqxoae2dnrf37...@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
There's a "Registration" item on the left menu at
http://www.icfpconference.org/icfp2011/ but it doesn't link to anywhere. Can
I just show up?
Sebastien
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------------------------------
Message: 5
Date: Wed, 6 Jul 2011 15:42:15 -0700
From: Michael Litchard <[email protected]>
Subject: [Haskell-beginners] Throughly confused by this error message
To: [email protected]
Message-ID:
<caezekyrn9rpst85sqads5hukgexett9rnavfxr4oacd2vpy...@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
I'd like someone to help me learn what questions to ask about this
error. I'm not sure how to contextualize. I will include code segments
that I think are important, and trust your questions will reveal what
I am leaving out.
HtmlParsing.lhs:81:25:
The first argument of ($) takes one argument,
but its type `URLString' has none
In the second argument of `($)', namely `initial $ method_GET'
In a stmt of a 'do' expression:
curlResp curl $ initial $ method_GET
In the expression:
do { let initial = urlInitial urlSequence
login = urlLogin urlSequence
....;
curlResp curl $ initial $ method_GET;
curlResp curl $ urlLogin urlSequence $ loginOpts user pass;
curlResp curl $ urlFlash1 urlSequence resourceOpts;
.... }
> generateResourceHtml :: Curl -> String -> String -> FilePath -> IO (Either
> String String)
> generateResourceHtml curl user pass ipFile = do
> urlSequence <- popURLrec ipFile
> let makeIDPage = do
> let initial = urlInitial urlSequence
> login = urlLogin urlSequence
> flash1 = urlFlash1 urlSequence
> flash2 = urlFlash2 urlSequence
> showWebForwards = urlShowWebForwards urlSequence
> quickCreate = urlQuickCreate urlSequence
> getResource = urlGetResource urlSequence
> curlResp curl $ initial $ method_GET
> curlResp curl $ urlLogin urlSequence $ loginOpts user pass
> curlResp curl $ urlFlash1 urlSequence resourceOpts
> curlResp curl $ urlFlash2 urlSequence resourceOpts
> curlResp curl $ urlShowWebForwards urlSequence resourceOpts
> curlResp curl $ urlQuickCreate urlSequence resourceOpts
> curlResp curl $ urlGetResource urlSequence resourceOpts
> runErrorT makeIDPage
> data URLSequence = URLSequence { urlInitial :: URLString
> , urlLogin :: URLString
> , urlFlash1 :: URLString
> , urlFlash2 :: URLString
> , urlShowWebForwards :: URLString
> , urlQuickCreate :: URLString
> , urlGetResource :: URLString
> } deriving Show
> curlResp :: (Error e, MonadError e m, MonadIO m) =>
> Curl -> URLString -> [CurlOption] -> m String --CurlResponse
> curlResp curl url opts = do
> resp <- liftIO $ (do_curl_ curl url opts :: IO CurlResponse)
> let code = respCurlCode resp
> status = respStatus resp
> if code /= CurlOK || status /= 200
> then throwError $ strMsg $ "Error: " ++ show code ++ " -- " ++ show
> status
> else return $ respBody resp
------------------------------
Message: 6
Date: Thu, 7 Jul 2011 08:46:29 +1000
From: Erik de Castro Lopo <[email protected]>
Subject: Re: [Haskell-beginners] Does one need a ticket to attend
ICFP?
To: [email protected]
Message-ID: <[email protected]>
Content-Type: text/plain; charset=US-ASCII
Sebastien Zany wrote:
> There's a "Registration" item on the left menu at
> http://www.icfpconference.org/icfp2011/ but it doesn't link to anywhere. Can
> I just show up?
I don't thnk registration is open yet.
Erik
--
----------------------------------------------------------------------
Erik de Castro Lopo
http://www.mega-nerd.com/
------------------------------
Message: 7
Date: Wed, 6 Jul 2011 16:03:08 -0700
From: Michael Litchard <[email protected]>
Subject: Re: [Haskell-beginners] Throughly confused by this error
message
To: [email protected]
Message-ID:
<caezekypan2bydsmfh86e8pler69ayu1yw9ijhfi5k921kb7...@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
You know, it's happened more than once. I'll send my problem to this
list, and a few minutes later I see someone really obviously wrong.
The problem is partially fixed in the sense that the changes I made
are producing errors that make sense to me.
On Wed, Jul 6, 2011 at 3:42 PM, Michael Litchard <[email protected]> wrote:
> I'd like someone to help me learn what questions to ask about this
> error. I'm not sure how to contextualize. I will include code segment> that I
> think are important, and trust your questions will reveal what
> I am leaving out.
>
>
>
> HtmlParsing.lhs:81:25:
> ? ?The first argument of ($) takes one argument,
> ? ?but its type `URLString' has none
> ? ?In the second argument of `($)', namely `initial $ method_GET'
> ? ?In a stmt of a 'do' expression:
> ? ? ? ? ?curlResp curl $ initial $ method_GET
> ? ?In the expression:
> ? ? ?do { let initial = urlInitial urlSequence
> ? ? ? ? ? ? ? login = urlLogin urlSequence
> ? ? ? ? ? ? ? ....;
> ? ? ? ? ? ? curlResp curl $ initial $ method_GET;
> ? ? ? ? ? ? curlResp curl $ urlLogin urlSequence $ loginOpts user pass;
> ? ? ? ? ? ? curlResp curl $ urlFlash1 urlSequence resourceOpts;
> ? ? ? ? ? .... }
>
>
>> generateResourceHtml :: Curl -> String -> String -> FilePath -> IO (Either
>> String String)
>> generateResourceHtml curl user pass ipFile = do
>> ? urlSequence <- popURLrec ipFile
>> ? let makeIDPage = do
>> ? ? ? let initial = urlInitial urlSequence
>> ? ? ? ? ? login = urlLogin urlSequence
>> ? ? ? ? ? flash1 = urlFlash1 urlSequence
>> ? ? ? ? ? flash2 = urlFlash2 urlSequence
>> ? ? ? ? ? showWebForwards = urlShowWebForwards urlSequence
>> ? ? ? ? ? quickCreate = urlQuickCreate urlSequence
>> ? ? ? ? ? getResource = ?urlGetResource urlSequence
>> ? ? ? curlResp curl $ initial $ method_GET
>> ? ? ? curlResp curl $ urlLogin urlSequence $ loginOpts user pass
>> ? ? ? curlResp curl $ urlFlash1 urlSequence resourceOpts
>> ? ? ? curlResp curl $ urlFlash2 urlSequence resourceOpts
>> ? ? ? curlResp curl $ urlShowWebForwards urlSequence resourceOpts
>> ? ? ? curlResp curl $ urlQuickCreate urlSequence resourceOpts
>> ? ? ? curlResp curl $ urlGetResource urlSequence resourceOpts
>> ? runErrorT makeIDPage
>
>> data URLSequence = URLSequence { urlInitial :: URLString
>> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?, urlLogin :: URLString
>> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?, urlFlash1 :: URLString
>> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?, urlFlash2 :: URLString
>> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?, urlShowWebForwards :: URLString
>> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?, urlQuickCreate :: URLString
>> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?, urlGetResource :: URLString
>> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?} deriving Show
>
>> curlResp :: (Error e, MonadError e m, MonadIO m) =>
>> ? ? ? Curl -> URLString -> [CurlOption] -> m String --CurlResponse
>> curlResp curl url opts = do
>> ? resp <- liftIO $ (do_curl_ curl url opts :: IO CurlResponse)
>> ? let code ? = respCurlCode resp
>> ? ? ? status = respStatus resp
>> ? if code /= CurlOK || status /= 200
>> ? ? ?then throwError $ strMsg $ "Error: " ++ show code ++ " -- " ++ show
>> status
>> ? ? ?else return $ respBody resp
>
------------------------------
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