Re: [Haskell-cafe] GHC vs GCC
On Sat, Mar 27, 2010 at 12:56 AM, Thomas DuBuisson thomas.dubuis...@gmail.com wrote: Using bang patterns didn't help almost anything here. Using rem instead of mod made the time go from 45s to 40s. Now, using -fvia-C really helped (when I used rem but not using mod). It went down to 10s. Bang patterns should have helped tons - it isn't GHC thats at fault here and yes it does tco. I attached a version w/ excessive bangs below. Did you compile with ghc --make -O3 -fforce-recomp? Does -O3 actually do anything? GHC only goes up to -O2. -- Dave Menendez d...@zednenem.com http://www.eyrie.org/~zednenem/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Why is it so different between 6.12.1 and 6.10.4_1 ?
I just start ghci from shell and do nothing else. In fact, i really donot
know `Monad ((-) a) ` . Would you mind expplain it ?
Yusaku Hashimoto wrote:
Did you import the module includes the instance of Monad ((-) e)
somewhere in your code loaded in ghci?
I tried this on a fresh ghci 6.12, but I got No instance error.
-nwn
On Sat, Mar 27, 2010 at 9:20 AM, zaxis z_a...@163.com wrote:
In 6.12.1 under archlinux
let f x y z = x + y + z
:t f
f :: (Num a) = a - a - a - a
:t (=) . f
(=) . f :: (Num a) = a - ((a - a) - a - b) - a - b
((=) . f) 1 (\f x - f x) 2
5
In 6.10.4_1 under freebsd
let f x y z = x + y + z
*Money :t f
f :: (Num a) = a - a - a - a
:t (=) . f
(=) . f :: (Monad ((-) a), Num a) = a - ((a - a) - a - b) - a
- b
((=) . f) 1 (\f x - f x) 2
interactive:1:1:
No instance for (Monad ((-) a))
arising from a use of `=' at interactive:1:1-5
Possible fix: add an instance declaration for (Monad ((-) a))
In the first argument of `(.)', namely `(=)'
In the expression: ((=) . f) 1 (\ f x - f x) 2
In the definition of `it': it = ((=) . f) 1 (\ f x - f x) 2
Sincerely!
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Re: [Haskell-cafe] Why is it so different between 6.12.1 and 6.10.4_1 ?
Why do you bother with the interior definition of f in there?
Because i want to try a C code style not layout style without `do` syntax
sugar .
Yusaku Hashimoto wrote:
fac n = let { f = foldr (*) 1 [1..n] } in f
Why do you bother with the interior definition of f in there?
fac = product . enumFromTo 1
let fac = do is_zero - (==0); if is_zero then return 1 else liftM2
(*) id (fac . pred)
-nwn
On Sat, Mar 27, 2010 at 9:59 AM, Ivan Lazar Miljenovic
ivan.miljeno...@gmail.com wrote:
zaxis z_a...@163.com writes:
In 6.10.4_1 under freebsd
let f x y z = x + y + z
*Money :t f
f :: (Num a) = a - a - a - a
:t (=) . f
(=) . f :: (Monad ((-) a), Num a) = a - ((a - a) - a - b) - a
- b
((=) . f) 1 (\f x - f x) 2
interactive:1:1:
No instance for (Monad ((-) a))
arising from a use of `=' at interactive:1:1-5
Possible fix: add an instance declaration for (Monad ((-) a))
In the first argument of `(.)', namely `(=)'
In the expression: ((=) . f) 1 (\ f x - f x) 2
In the definition of `it': it = ((=) . f) 1 (\ f x - f x) 2
Some definitions and exports got changed, so in 6.12 the (- a) Monad
instance is exported whereas in 6.10 it isn't.
fac n = let { f = foldr (*) 1 [1..n] } in f
Why do you bother with the interior definition of f in there?
fac = product . enumFromTo 1
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ivan.miljeno...@gmail.com
IvanMiljenovic.wordpress.com
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Re: [Haskell-cafe] GHC vs GCC
David Menendez wrote: On Sat, Mar 27, 2010 at 12:56 AM, Thomas DuBuisson thomas.dubuis...@gmail.com wrote: Using bang patterns didn't help almost anything here. Using rem instead of mod made the time go from 45s to 40s. Now, using -fvia-C really helped (when I used rem but not using mod). It went down to 10s. Bang patterns should have helped tons - it isn't GHC thats at fault here and yes it does tco. I attached a version w/ excessive bangs below. Did you compile with ghc --make -O3 -fforce-recomp? Does -O3 actually do anything? GHC only goes up to -O2. Well GHC has an -O3[1], but it's not a good idea to use it. Some of the optimizations that -O3 does can result in slower code for particular programs. Whereas -O2 is safe and never results in pessimizations. [1] Unless recent versions have removed it. -- Live well, ~wren ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Why is it so different between 6.12.1 and 6.10.4_1 ?
zaxis z_a...@163.com writes: Why do you bother with the interior definition of f in there? Because i want to try a C code style not layout style without `do` syntax sugar . Haskell /= C, so stop trying to code as if it is. If you like C so much, then use C. -- Ivan Lazar Miljenovic ivan.miljeno...@gmail.com IvanMiljenovic.wordpress.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC vs GCC
Hi, Rafael Almeida wrote: On Fri, Mar 26, 2010 at 6:49 PM, Jason Dagit da...@codersbase.com wrote: Using bang patterns didn't help almost anything here. Using rem instead of mod made the time go from 45s to 40s. Now, using -fvia-C really helped (when I used rem but not using mod). It went down to 10s. What's going on here? Doesn't ghc do tail recursion optimization? I see similar surprising results here on x86_64 Linux, GHC 6.10.4 (version with bangs): -fasm real0m25.239s user0m25.218s sys 0m0.012s -via-c real0m8.699s user0m8.641s sys 0m0.020s Best, -- Grzegorz -- View this message in context: http://old.nabble.com/GHC-vs-GCC-tp28045806p28050734.html Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Internet game servers in Haskell?
Has anyone ever written a server in Haskell for managing live game-playing (any game) across the internet? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC vs GCC vs JHC
Hi John, Any chance of seeing the benchmark? You're not the only one with an optimising compiler tucked away somewhere :-) I have one benchmark where I outperform GHC by 21 times, although saying it's artificial is a bit of an understatement... Thanks, Neil On Fri, Mar 26, 2010 at 6:27 PM, John Meacham j...@repetae.net wrote: Here are jhc's timings for the same programs on my machine. gcc and ghc both used -O3 and jhc had its full standard optimizations turned on. jhc: ./hs.out 5.12s user 0.07s system 96% cpu 5.380 total gcc: ./a.out 5.58s user 0.00s system 97% cpu 5.710 total ghc: ./try 31.11s user 0.00s system 96% cpu 32.200 total As you can see, jhc shines at this example, actually beating gcc -O3. It isn't too surprising, this is exactly the sort of haskell code that jhc excels at. John -- John Meacham - ⑆repetae.net⑆john⑈ - http://notanumber.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Randomized N-Queens
Ronald Guida wrote:
Hi,
I'm trying to solve the N-queens problem, but with a catch: I want to
generate solutions in a random order.
I know how to solve the N-queens problem; my solver (below) generates all
possible solutions. What I am trying to do is generate solutions in a
random order by somehow randomizing the order in which nextRow considers
the unused columns. I tried adding a random number generator to the
solution state; the problem with this approach is that whenever the solver
backtracks, the state of the random number generator backtracks along with
it. In effect, I am selecting a random, but fixed, permutation for each
row, and then I am applying that same set of permutations along all
computational paths. Whenever I consider row R, regardless of which path I
have taken, I am applying row R's permutation to the unused columns.
This is not the behavior I want. I want each computational path to use a
new, different permutation for each row. On the other hand I also want to
be able to take the first few solutions without waiting for all possible
solutions to be generated. How might I go about doing this?
[...]
data (RandomGen g) = SolutionState g = SolutionState
{ solnBoard :: Board
, solnUnusedColumns :: [Int]
, solnRandomGen :: g
}
nextRow :: (RandomGen g) = Int - Int - StateT (SolutionState g) [] ()
It's a matter of choosing the right monad stack. In particular, putting
the random number generator into the solution state pretty much forces
the undesired behavior. Random numbers are best put in a separate monad
(transformer), for reasons of abstraction which are outlined here:
http://lukepalmer.wordpress.com/2009/01/17/use-monadrandom/
http://apfelmus.nfshost.com/articles/random-permutations.html
Also, it's not really necessary to use the state monad to store the
solution, using a plain old parameter works just fine, as the following
code illustrates:
import Control.Monad.Random -- from the MonadRandom package
-- generate a random permutation
randomPerm :: MonadRandom r = [a] - r [a]
randomPerm xs = go (length xs) xs
where
go 0 [] = return []
go n xs = do
k - getRandomR (0,n-1)
let (x,xs') = select k xs
liftM (x:) $ go (n-1) xs'
select 0 (x:xs) = (x,xs)
select k (x:xs) = let (y,ys) = select (k-1) xs in (y,x:ys)
-- 8 queens
type Pos = (Int,Int)
attacks (x1,y1) (x2,y2) =
x1 == x2
|| y1 == y2
|| x1 - x2 == y1 - y2
|| x2 - x1 == y1 - y2
type Solution = [Pos]
solve :: Rand StdGen [Solution]
solve = solve' 8 []
where
solve' 0 qs = return [qs]
solve' row qs =
liftM concat . mapM putQueen = randomPerm [1..8]
where
putQueen col
| any (q `attacks`) qs = return []
| otherwise= solve' (row-1) (q:qs)
where q = (row,col)
test seed = evalRand solve $ mkStdGen seed
Regards,
Heinrich Apfelmus
--
http://apfelmus.nfshost.com
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Re: [Haskell-cafe] Why is it so different between 6.12.1 and 6.10.4_1 ?
Of course, you are wrong ! C is VERY important for almost every programmer
in the world! Why cannot C programmer use haskell ? And Why does haskell
support C code style ?
Ivan Miljenovic wrote:
zaxis z_a...@163.com writes:
Why do you bother with the interior definition of f in there?
Because i want to try a C code style not layout style without `do` syntax
sugar .
Haskell /= C, so stop trying to code as if it is. If you like C so
much, then use C.
--
Ivan Lazar Miljenovic
ivan.miljeno...@gmail.com
IvanMiljenovic.wordpress.com
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Re: [Haskell-cafe] Why is it so different between 6.12.1 and 6.10.4_1 ?
I think Miljenovic was asking about this (I removed explicit braces):
fac n = let f = foldr (*) 1 [1..n] in f
Which is strictly equivalent to:
fac n = foldr (*) 1 [1..n]
Translated into C, this is kind of like doing this:
int add(int x, int y)
{
int sum = x + y;
return sum;
}
instead of this:
int add(int x, int y)
{
return x + y;
}
I find it very cumbersome (though not *difficult*) and painful to use
a C style of programming with Haskell, so I am not sure what you mean
when you ask why Haskell supports C style. Are you talking about
mutable state, syntax, or something else?
--Dietrich
On 2010 March 27, at 4:28, zaxis wrote:
Of course, you are wrong ! C is VERY important for almost every
programmer
in the world! Why cannot C programmer use haskell ? And Why does
haskell
support C code style ?
Ivan Miljenovic wrote:
zaxis z_a...@163.com writes:
Why do you bother with the interior definition of f in there?
Because i want to try a C code style not layout style without `do`
syntax
sugar .
Haskell /= C, so stop trying to code as if it is. If you like C so
much, then use C.
--
Ivan Lazar Miljenovic
ivan.miljeno...@gmail.com
IvanMiljenovic.wordpress.com
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Re: [Haskell-cafe] GHC vs GCC
On Sat, Mar 27, 2010 at 12:43 AM, Rafael Almeida almeida...@gmail.comwrote: On Fri, Mar 26, 2010 at 6:49 PM, Jason Dagit da...@codersbase.com wrote: On Fri, Mar 26, 2010 at 2:33 PM, Bryan O'Sullivan b...@serpentine.com wrote: On Fri, Mar 26, 2010 at 10:46 AM, Rafael Cunha de Almeida almeida...@gmail.com wrote: During a talk with a friend I came up with two programs, one written in C and another in haskell. Your Haskell code builds a huge thunked accumulator value, so of course it's slow (put bang patterns on all arguments). Also, you should use rem instead of mod. Make those tiny changes and you'll get a 5x speedup, to half the performance of the C code. Interesting. I had to add -fvia-C to get within half the performance of C. Just bang patterns and rem and I'm 1/5th of C. I'm on a x86_64 machine. I wonder if that plays in. Jason Using bang patterns didn't help almost anything here. Using rem instead of mod made the time go from 45s to 40s. Now, using -fvia-C really helped (when I used rem but not using mod). It went down to 10s. It's worth pointing out that there's a bit of bang-pattern mysticism going on in this conversation (which has not been uncommon of late!). A non-buggy strictness analyzer should expose the strictness of these functions without difficulty. If bang patterns make any difference at all with a -O flag, either there's a strictness analysis bug, or some very interesting effects from shifting the order of forcing of strict variables. Putting in bang patterns is a good idea to plug the obvious space leak when run without optimization, but isn't going to make a difference for optimizing compilation of obviously-strict functions. -Jan-Willem Maessen ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC vs GCC
On 10-03-26 11:50 PM, wren ng thornton wrote: Well GHC has an -O3[1], but it's not a good idea to use it. Some of the optimizations that -O3 does can result in slower code for particular programs. Whereas -O2 is safe and never results in pessimizations. Slightly off topic, but ACOVEA may be an interesting item to see here. http://www.coyotegulch.com/products/acovea/ Pom. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC vs GCC
On Fri, 26 Mar 2010 21:56:16 -0700, Thomas DuBuisson wrote: Using bang patterns didn't help almost anything here. Using rem instead of mod made the time go from 45s to 40s. Now, using -fvia-C really helped (when I used rem but not using mod). It went down to 10s. Bang patterns should have helped tons - it isn't GHC thats at fault here and yes it does tco. I attached a version w/ excessive bangs below. Did you compile with ghc --make -O3 -fforce-recomp? I can verify that it is not bang patterns that helped, it is an issue related to `mod' vs. `rem'. mod w/o bang: 30.73s user 0.15s system 99% cpu 30.954 total rem w/o bang: 6.52s user 0.00s system 99% cpu 6.528 total mod w/ bang: 30.53s user 0.25s system 99% cpu 30.878 total rem w/ bang: 6.34s user 0.00s system 99% cpu 6.359 total Compiled with: ghc --make -fexcess-precision -funbox-strict-fields -O3 -Wall -optc-O3 -optc-march=native -optl-Wl,-s -fvia-c -fforce-recomp test.hs -o test-hs And for comparison, c version: 4.35s user 0.04s system 99% cpu 4.403 total Linux 2.6.33-ARCH #1 SMP PREEMPT Mon Mar 15 19:11:52 CET 2010 x86_64 GenuineIntel GNU/Linux Best, jxy -- Jc/*__o/* X\ * (__ Y*/\ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Are there any female Haskellers?
Hi all, from the names of people on the list it seems that all users here are males. Just out of curiosity are there any female users here, or are we guys only at the moment? Günther ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Testing for valid data
When I'm learning a new language I like to translate old programs into the new language as a test of my understanding. However, many of the old programs are from old programming texts, many written in the time of punch-cards for batch processing, and many containing significant amounts of code that only tests for valid data. Should we still be writing programs in this fashion, or acknowledge the fact that better tools for pre-screening data are now available and code only for the problem at hand? Michael ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
Why? Are you going to make dirty jokes or something :) Nevertheless, I guess you're right. There are very few females in most of the CS topics, and haskell is no different. I know at least 1 (one!) female who implemented software using haskell for her phd thesis, though. Cheers! 2010/3/27 Günther Schmidt gue.schm...@web.de Hi all, from the names of people on the list it seems that all users here are males. Just out of curiosity are there any female users here, or are we guys only at the moment? Günther ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Ozgur Akgun ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
-Ursprüngliche Nachricht- Von: Günther Schmidt gue.schm...@web.de Gesendet: 27.03.2010 16:14:57 An: haskell-cafe@haskell.org Betreff: [Haskell-cafe] Are there any female Haskellers? Hi all, from the names of people on the list it seems that all users here are males. Just out of curiosity are there any female users here, or are we guys only at the moment? Günther I'm pretty sure that Phil(l?)ip(p?)a Cowderoy is female, I've also seen a couple of other female names here and on the beginners list. (Since Ashley Yakeley seems to be located in the USA, I dare not guess whether Ashley is a man's name or a woman's in this case.) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
Ozgur Akgun wrote: Nevertheless, I guess you're right. There are very few females in most of the CS topics, and haskell is no different. This is my experience too. Although note that apparently the world's very first computer programmer was apparently a woman... ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
I worked with a female student on a Haskell project last summer :) She's not into being member of a mailing list or a user group but she exists. On Sat, Mar 27, 2010 at 6:51 PM, Andrew Coppin andrewcop...@btinternet.com wrote: Ozgur Akgun wrote: Nevertheless, I guess you're right. There are very few females in most of the CS topics, and haskell is no different. This is my experience too. Although note that apparently the world's very first computer programmer was apparently a woman... ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] chp-plus doesn't install
I'm getting these errors (ghc 6.10.4 on Linux x86_64): Building chp-plus-1.1.0... [1 of 9] Compiling Control.Concurrent.CHP.Test ( Control/Concurrent/CHP/Test.hs, dist/build/Control/Concurrent/CHP/Test.o ) [2 of 9] Compiling Control.Concurrent.CHP.Console ( Control/Concurrent/CHP/Console.hs, dist/build/Control/Concurrent/CHP/Console.o ) [3 of 9] Compiling Control.Concurrent.CHP.Connect ( Control/Concurrent/CHP/Connect.hs, dist/build/Control/Concurrent/CHP/Connect.o ) Control/Concurrent/CHP/Connect.hs:146:67: Couldn't match expected type `ChanOpts a' against inferred type `ConnectableParam (Chanout a)' In the first argument of `oneToOneChannel'', namely `o' In the second argument of `($)', namely `oneToOneChannel' o' In the first argument of `(=)', namely `((writer reader) $ oneToOneChannel' o)' Control/Concurrent/CHP/Connect.hs:152:67: Couldn't match expected type `ChanOpts a' against inferred type `ConnectableParam (Chanin a)' In the first argument of `oneToOneChannel'', namely `o' In the second argument of `($)', namely `oneToOneChannel' o' In the first argument of `(=)', namely `((reader writer) $ oneToOneChannel' o)' etc. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
Maybe not on the list, but there certainly are in academia. I can think of several off the top of my head. 2010/3/27 Günther Schmidt gue.schm...@web.de: Hi all, from the names of people on the list it seems that all users here are males. Just out of curiosity are there any female users here, or are we guys only at the moment? Günther ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] chp-plus doesn't install
Colin Paul Adams wrote: I'm getting these errors (ghc 6.10.4 on Linux x86_64): Building chp-plus-1.1.0... [1 of 9] Compiling Control.Concurrent.CHP.Test ( Control/Concurrent/CHP/Test.hs, dist/build/Control/Concurrent/CHP/Test.o ) [2 of 9] Compiling Control.Concurrent.CHP.Console ( Control/Concurrent/CHP/Console.hs, dist/build/Control/Concurrent/CHP/Console.o ) [3 of 9] Compiling Control.Concurrent.CHP.Connect ( Control/Concurrent/CHP/Connect.hs, dist/build/Control/Concurrent/CHP/Connect.o ) Control/Concurrent/CHP/Connect.hs:146:67: Couldn't match expected type `ChanOpts a' against inferred type `ConnectableParam (Chanout a)' In the first argument of `oneToOneChannel'', namely `o' In the second argument of `($)', namely `oneToOneChannel' o' In the first argument of `(=)', namely `((writer reader) $ oneToOneChannel' o)' I don't immediately have a GHC 6.10.4 machine to hand, but that is an odd error. Here is the code in question: instance ConnectableExtra (Chanout a) (Chanin a) where type ConnectableParam (Chanout a) = ChanOpts a connectExtra o = (=) ((writer reader) $ oneToOneChannel' o) (based on the class: class ConnectableExtra l r where type ConnectableParam l connectExtra :: ConnectableParam l - ((l, r) - CHP ()) - CHP () ) So I don't see why there is a type mismatch; ConnectableParam (Chanout a) is ChanOpts a. I don't know if it's somehow confused by the recently added similar instance: instance ConnectableExtra (Chanout a) (Shared Chanin a) where type ConnectableParam (Chanout a) = ChanOpts a connectExtra o = (=) ((writer reader) $ oneToAnyChannel' o) There's no conflict between the two instances, though. I wonder if making ConnectableParam depend on l and r would fix it. I'll look further into this when I get onto a 6.10.4 machine. Thanks, Neil. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC vs GCC
Jan-Willem Maessen wrote: It's worth pointing out that there's a bit of bang-pattern mysticism going on in this conversation (which has not been uncommon of late!). A non-buggy strictness analyzer should expose the strictness of these functions without difficulty. Could the result of strictness analysis reported in terms of the original Haskell program? ghc -O2 -ddump-strictness test.hs test.hs:3:1: Top-level function `foo' is found to be strict in the first and third argument. This could help people gain confidence in the strictness analyzer. Tillmann ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
On Sat, Mar 27, 2010 at 9:05 AM, Daniel Fischer daniel.is.fisc...@web.dewrote: -Ursprüngliche Nachricht- Von: Günther Schmidt gue.schm...@web.de Gesendet: 27.03.2010 16:14:57 An: haskell-cafe@haskell.org Betreff: [Haskell-cafe] Are there any female Haskellers? Hi all, from the names of people on the list it seems that all users here are males. Just out of curiosity are there any female users here, or are we guys only at the moment? Günther I'm pretty sure that Phil(l?)ip(p?)a Cowderoy is female, I've also seen a couple of other female names here and on the beginners list. (Since Ashley Yakeley seems to be located in the USA, I dare not guess whether Ashley is a man's name or a woman's in this case.) Ashley Yakeley is a man. I work with several female Haskellers. And I've met several others who are at universities or use Haskell on the side. In general, I'd say women in computer science are a minority. I would say mathematics has a higher percentage of women than computer science from my own anecdotal experience. Why are there so few women in computer science? I don't know but it's an interesting question. One professor I was talking to about this subject said he felt that at his university when CS was a part of math there were more women and when it became part of engineering the percentage of women dropped. It's possible that there are gender differences that cause men to be attracted to this field more frequently than women. I'm hesitant to say that's the underlying reason though. I suspect the following, based on conversations I've had with women in the field. For some reason it started out as a male dominated field. Let's assume for cultural reasons. Once it became a male dominated field, us males unknowingly made the work and learning environments somewhat hostile or unattractive to women. I bet I would feel out of place if I were the only male in a class of 100 women. Anyway, those are just observations I've made. Don't take any of it too seriously and I certainly don't mean to offend anyone. I know gender differences can be quite controversial at times. Jason ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
To say this in scientific headline jargon, It´s a matter of division of work, time, and dimorphic fixation of abilities in the brain by natural selection trough dimorphic development of the brain of men and women by different genetic sequences. I don´t know any kind of tool more flexible and powerful than a computer language. Men are good at making tools and using them. They invested more in engineering because this activity were more critical for their success than in the case of women. Sociological or cultural explanations don´t explain the universal tendencies and habilities across cultures and time. The reasons for the sexual differences in mathematical abilities are different, because math abilities are not a -primary- reason for survival. Tools engineering and mastering is. If this is politically incorrect I beg you pardon, but this is my honest theory about that. My other hobby is evolution and evolutionary psichology. I really recommend to learn about it. Hope that this cold answer don't end this funny thread ;( Best wishes Alberto 2010/3/27 Jason Dagit da...@codersbase.com On Sat, Mar 27, 2010 at 9:05 AM, Daniel Fischer daniel.is.fisc...@web.dewrote: -Ursprüngliche Nachricht- Von: Günther Schmidt gue.schm...@web.de Gesendet: 27.03.2010 16:14:57 An: haskell-cafe@haskell.org Betreff: [Haskell-cafe] Are there any female Haskellers? Hi all, from the names of people on the list it seems that all users here are males. Just out of curiosity are there any female users here, or are we guys only at the moment? Günther I'm pretty sure that Phil(l?)ip(p?)a Cowderoy is female, I've also seen a couple of other female names here and on the beginners list. (Since Ashley Yakeley seems to be located in the USA, I dare not guess whether Ashley is a man's name or a woman's in this case.) Ashley Yakeley is a man. I work with several female Haskellers. And I've met several others who are at universities or use Haskell on the side. In general, I'd say women in computer science are a minority. I would say mathematics has a higher percentage of women than computer science from my own anecdotal experience. Why are there so few women in computer science? I don't know but it's an interesting question. One professor I was talking to about this subject said he felt that at his university when CS was a part of math there were more women and when it became part of engineering the percentage of women dropped. It's possible that there are gender differences that cause men to be attracted to this field more frequently than women. I'm hesitant to say that's the underlying reason though. I suspect the following, based on conversations I've had with women in the field. For some reason it started out as a male dominated field. Let's assume for cultural reasons. Once it became a male dominated field, us males unknowingly made the work and learning environments somewhat hostile or unattractive to women. I bet I would feel out of place if I were the only male in a class of 100 women. Anyway, those are just observations I've made. Don't take any of it too seriously and I certainly don't mean to offend anyone. I know gender differences can be quite controversial at times. Jason ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC vs GCC
On Sat, Mar 27, 2010 at 1:45 PM, Tillmann Rendel ren...@mathematik.uni-marburg.de wrote: Jan-Willem Maessen wrote: It's worth pointing out that there's a bit of bang-pattern mysticism going on in this conversation (which has not been uncommon of late!). A non-buggy strictness analyzer should expose the strictness of these functions without difficulty. Could the result of strictness analysis reported in terms of the original Haskell program? That would be nice. Even if you're willing to read core, I'm not aware that the output of -ddump-stranal is explained anywhere. Incidentally, the results of -ddump-simpl when running on -O2 say that GHC has unboxed every argument except the first argument to rangeJ. -- Dave Menendez d...@zednenem.com http://www.eyrie.org/~zednenem/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Are there any female Haskellers?
Alberto G. Corona agocorona at gmail.com writes: Hope that this cold answer don't end this funny thread ;( Those concerned with Haskellers to Haskellinas ration can always employ this technique: http://www.newton.dep.anl.gov/askasci/bio99/bio99128.htm Any volunteers? :) -- Gracjan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
http://en.wikipedia.org/wiki/Grace_Hopper http://en.wikipedia.org/wiki/Grace_HopperA heck of a lady. On Sat, Mar 27, 2010 at 12:51 PM, Andrew Coppin andrewcop...@btinternet.com wrote: Ozgur Akgun wrote: Nevertheless, I guess you're right. There are very few females in most of the CS topics, and haskell is no different. This is my experience too. Although note that apparently the world's very first computer programmer was apparently a woman... ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
2010/03/27 Alberto G. Corona agocor...@gmail.com: To say this in scientific headline jargon, it's a matter of division of work, time, and dimorphic fixation of abilities in the brain by natural selection trough dimorphic development of the brain of men and women by different genetic sequences. I don't know any kind of tool more flexible and powerful than a computer language. Men are good at making tools and using them. They invested more in engineering because this activity were more critical for their success than in the case of women. Sociological or cultural explanations don't explain the universal tendencies and habilities across cultures and time. In this passage, you seem to attribute to men a relatively great adaptation for making using tools, relative to women. You suggest this applies to computer languages -- excellent tools -- and this explains the relative absence of women in computing. It's hard to take your remarks seriously; consider: . There is no single adaptation for tool using. Men differ greatly in their aptitude for working with different kinds of tools. . The relevance of tools in women's lives is well known; there are few cultures that have not allocated some essential domain of work -- fabric arts, tanning, cooking, picking certain plants -- to women. It's hard to see any support for the notion that tools are more (or less) critical for the evolutionary success of men. Though this may be your honest theory, you don't offer much support for it. When offering a theory as to the relative success of one movie over another, I suppose there is not a great burden of proof; but carelessness in the matter of which kind of person can do which kind of work has hurt too many people for too long. -- Jason Dusek ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Why is it so different between 6.12.1 and 6.10.4_1 ?
Hmm, When a ghci was started, there should be the only loaded module
(Prelude.) And in both 6.10 and 6.12, such instance is not defined or
exported in its Prelude. So please try `ghci -ignore-dot-ghci`. It
invokes ghci without reading ~/.ghci and ./.ghci.
And `((-) a)` is known as the Reader Monad, `a` can be regarded as
the environment. My typical usage of that is like following:
import Control.Monad
data Vec = Vec { x :: Int, y :: Int }
absolute :: Vec - Double
absolute = sqrt . fromIntegral . liftM2 (+) (square . x) (square . y)
where
square a = a * a
The definition of `absolute` above can be rewritten as
absolute p = sqrt . fromIntegral $ square (x p) + square (y p)
where
square a = a * a
How `square . x` and `square . y` share the argument? Because `Monad
((-) a)` is defined as
instance Monad ((-) a) where
return x = \a - x
m = f = \a - f (m a) a
Note `(=)` propagates `a` into both of its arguments. That's why the
functions read same argument.
HTH
-nwn
On Sat, Mar 27, 2010 at 3:31 PM, zaxis z_a...@163.com wrote:
I just start ghci from shell and do nothing else. In fact, i really donot
know `Monad ((-) a) ` . Would you mind expplain it ?
Yusaku Hashimoto wrote:
Did you import the module includes the instance of Monad ((-) e)
somewhere in your code loaded in ghci?
I tried this on a fresh ghci 6.12, but I got No instance error.
-nwn
On Sat, Mar 27, 2010 at 9:20 AM, zaxis z_a...@163.com wrote:
In 6.12.1 under archlinux
let f x y z = x + y + z
:t f
f :: (Num a) = a - a - a - a
:t (=) . f
(=) . f :: (Num a) = a - ((a - a) - a - b) - a - b
((=) . f) 1 (\f x - f x) 2
5
In 6.10.4_1 under freebsd
let f x y z = x + y + z
*Money :t f
f :: (Num a) = a - a - a - a
:t (=) . f
(=) . f :: (Monad ((-) a), Num a) = a - ((a - a) - a - b) - a
- b
((=) . f) 1 (\f x - f x) 2
interactive:1:1:
No instance for (Monad ((-) a))
arising from a use of `=' at interactive:1:1-5
Possible fix: add an instance declaration for (Monad ((-) a))
In the first argument of `(.)', namely `(=)'
In the expression: ((=) . f) 1 (\ f x - f x) 2
In the definition of `it': it = ((=) . f) 1 (\ f x - f x) 2
Sincerely!
-
fac n = let { f = foldr (*) 1 [1..n] } in f
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Re: [Haskell-cafe] Are there any female Haskellers?
So the first computer nerd was a women??!!! ;-) ;-) ;-) On Sat, Mar 27, 2010 at 9:06 PM, John Van Enk vane...@gmail.com wrote: http://en.wikipedia.org/wiki/Grace_Hopper A heck of a lady. On Sat, Mar 27, 2010 at 12:51 PM, Andrew Coppin andrewcop...@btinternet.com wrote: Ozgur Akgun wrote: Nevertheless, I guess you're right. There are very few females in most of the CS topics, and haskell is no different. This is my experience too. Although note that apparently the world's very first computer programmer was apparently a woman... ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
On Sat, Mar 27, 2010 at 2:22 PM, Peter Verswyvelen bugf...@gmail.com wrote: So the first computer nerd was a women??!!! ;-) ;-) ;-) Yeah, and she was so attractive that the entire male gender spent the next 50 years trying to impress her. Luke On Sat, Mar 27, 2010 at 9:06 PM, John Van Enk vane...@gmail.com wrote: http://en.wikipedia.org/wiki/Grace_Hopper A heck of a lady. On Sat, Mar 27, 2010 at 12:51 PM, Andrew Coppin andrewcop...@btinternet.com wrote: Ozgur Akgun wrote: Nevertheless, I guess you're right. There are very few females in most of the CS topics, and haskell is no different. This is my experience too. Although note that apparently the world's very first computer programmer was apparently a woman... ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
2010/3/27 Jason Dusek jason.du...@gmail.com 2010/03/27 Alberto G. Corona agocor...@gmail.com: To say this in scientific headline jargon, it's a matter of division of work, time, and dimorphic fixation of abilities in the brain by natural selection trough dimorphic development of the brain of men and women by different genetic sequences. I don't know any kind of tool more flexible and powerful than a computer language. Men are good at making tools and using them. They invested more in engineering because this activity were more critical for their success than in the case of women. Sociological or cultural explanations don't explain the universal tendencies and habilities across cultures and time. In this passage, you seem to attribute to men a relatively great adaptation for making using tools, relative to women. You suggest this applies to computer languages -- excellent tools -- and this explains the relative absence of women in computing. It's hard to take your remarks seriously; consider: . There is no single adaptation for tool using. Men differ greatly in their aptitude for working with different kinds of tools. The adaptation consist in the plasure for using such tools, to harness his power to play with them that is, to invest in them. The mean male play an appreciate new tools more than women. that is universal. Additionally it is clear that some mathematical abilities in which men are better are related with the use of tools. The fact that men and woman have different abilities and tendencies that match these abilities is beyond doubt. Cerebral scanners shows that even there are large differences in which are of the brain is used for each purpose in men and women. That does not ban anyone to do whatever they please. . The relevance of tools in women's lives is well known; there are few cultures that have not allocated some essential domain of work -- fabric arts, tanning, cooking, picking certain plants -- to women. It's hard to see any support for the notion that tools are more (or less) critical for the evolutionary success of men. yes. but these tools are not the object of their pleasure. they just use them for a purpose. Though this may be your honest theory, you don't offer much support for it. When offering a theory as to the relative success of one movie over another, I suppose there is not a great burden of proof; but carelessness in the matter of which kind of person can do which kind of work has hurt too many people for too long. This is off topic. and i can not write extensively about that here but is just a consequence of the application of evolution to the human speciehttp://en.wikipedia.org/wiki/Evolutionary_psychology. Here you can find some answer to your objections. I strongly disagree with your point. Science is made of theories. If we can even discuss them then we are in the middle age of the politically correct empire, in a civilization that has decide to stop thinking, that regret his achievements and that only look back to find excuses to ate deeper himself. -- Jason Dusek ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
My friend named her cat Haskell after the language :) John -- John Meacham - ⑆repetae.net⑆john⑈ - http://notanumber.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Testing for valid data
michael rice nowg...@yahoo.com writes: When I'm learning a new language I like to translate old programs into the new language as a test of my understanding. However, many of the old programs are from old programming texts, many written in the time of punch-cards for batch processing, and many containing significant amounts of code that only tests for valid data. Should we still be writing programs in this fashion, or acknowledge the fact that better tools for pre-screening data are now available and code only for the problem at hand? Hm - I remember test suites in a dynamically typed program with test case upon test case checking that functions expecting integers would throw an exception when given a string, and so on. Doesn't seem that long ago either.. I think the whole -- well, no, but half, maybe -- point of Haskell is that the static type system proves data validity throughout the program. And half the trick of writing correct programs is to design your data types to constrain the possible values to valid ones. -k -- If I haven't seen further, it is by standing in the footprints of giants ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
I bet there are some people here who think women are very idiot to be knowledgeable about haskell. Cheers ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Are there any female Haskellers?
Hi guys (and I mean it), so, in short, no female haskellers ... Bare one which sent me an email directly, but it looks like she's not ready to come out of the closet yet. Günther ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
If you are looking for a real first - http://en.wikipedia.org/wiki/Ada_Lovelace - she is even credited with writing the first algorithm for machine execution. On 27 Mar 2010, at 20:06, John Van Enk wrote: http://en.wikipedia.org/wiki/Grace_Hopper A heck of a lady. On Sat, Mar 27, 2010 at 12:51 PM, Andrew Coppin andrewcop...@btinternet.com wrote: Ozgur Akgun wrote: Nevertheless, I guess you're right. There are very few females in most of the CS topics, and haskell is no different. This is my experience too. Although note that apparently the world's very first computer programmer was apparently a woman... ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Testing for valid data
Hi Ketil, Good point, but I think it side-steps the question. Haskell coughs on a data value. Do we grep our data, finding and fixing the offender, or build extensive data tests into our application code? Michael --- On Sat, 3/27/10, Ketil Malde ke...@malde.org wrote: From: Ketil Malde ke...@malde.org Subject: Re: [Haskell-cafe] Testing for valid data To: haskell-cafe@haskell.org Date: Saturday, March 27, 2010, 5:20 PM michael rice nowg...@yahoo.com writes: When I'm learning a new language I like to translate old programs into the new language as a test of my understanding. However, many of the old programs are from old programming texts, many written in the time of punch-cards for batch processing, and many containing significant amounts of code that only tests for valid data. Should we still be writing programs in this fashion, or acknowledge the fact that better tools for pre-screening data are now available and code only for the problem at hand? Hm - I remember test suites in a dynamically typed program with test case upon test case checking that functions expecting integers would throw an exception when given a string, and so on. Doesn't seem that long ago either.. I think the whole -- well, no, but half, maybe -- point of Haskell is that the static type system proves data validity throughout the program. And half the trick of writing correct programs is to design your data types to constrain the possible values to valid ones. -k -- If I haven't seen further, it is by standing in the footprints of giants ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
Alberto G. Corona wrote: because math abilities are not a -primary- reason for survival. Tools engineering and mastering is. I don't see the difference. Being able to use a lever, wheel, pulley, fire,... is obviously helpful for survival. But intellectual tools like mathematics, logic, and computer science don't bear any particular relation to physical tools. If someone's adept at using hammers, pliers,... there's no reason to suspect that they'd be adept with reasoning puzzles. And just because someone's good at category theory is no reason to suspect they'd be able to repair a car. Do not be misled by the fact that CS departments are often lumped in with engineering. For that matter, do not be misled by modern engineering which bears little resemblance to any tool-using evolutionary advantage that may have molded homo sapiens. -- Live well, ~wren ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
wren ng thornton wrote: Alberto G. Corona wrote: because math abilities are not a -primary- reason for survival. Tools engineering and mastering is. I don't see the difference. (That is, the difference between CS and mathematics. Conversely, I don't see the similarity between physical tools and intellectual tools.) Being able to use a lever, wheel, pulley, fire,... is obviously helpful for survival. But intellectual tools like mathematics, logic, and computer science don't bear any particular relation to physical tools. If someone's adept at using hammers, pliers,... there's no reason to suspect that they'd be adept with reasoning puzzles. And just because someone's good at category theory is no reason to suspect they'd be able to repair a car. Do not be misled by the fact that CS departments are often lumped in with engineering. For that matter, do not be misled by modern engineering which bears little resemblance to any tool-using evolutionary advantage that may have molded homo sapiens. -- Live well, ~wren ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
On Sat, Mar 27, 2010 at 1:56 PM, Jason Dagit da...@codersbase.com wrote: For some reason it started out as a male dominated field. Let's assume for cultural reasons. Once it became a male dominated field, us males unknowingly made the work and learning environments somewhat hostile or unattractive to women. I bet I would feel out of place if I were the only male in a class of 100 women. Is this really true? I've heard rumors that in the early days of programming, that women were in the majority, or at least they represented a much greater proportion of programmers than they do now. I seem to recall that this started to change sometime in the 60s. Of course, I can't recall when or where I heard these stories, and I'm not sure that my source was reliable, so I might be completely off on this count. Best, Leon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC vs GCC vs JHC
On Sat, Mar 27, 2010 at 3:25 AM, Neil Mitchell ndmitch...@gmail.com wrote: Hi John, Any chance of seeing the benchmark? You're not the only one with an optimising compiler tucked away somewhere :-) Neil, for some reason John's reply didn't thread with the rest of the thread. Probably because he changed the subject. He was referring to this thread: http://www.haskell.org/pipermail/haskell-cafe/2010-March/075151.html Jason ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
On Sat, Mar 27, 2010 at 23:09, Leon Smith wrote: I've heard rumors that in the early days of programming, that women were in the majority, or at least they represented a much greater proportion of programmers than they do now. They're not just rumors: http://www.witi.com/center/witimuseum/halloffame/1997/eniac.php Sean ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC vs GCC vs JHC
John Meacham wrote: Here are jhc's timings for the same programs on my machine. gcc and ghc both used -O3 and jhc had its full standard optimizations turned on. jhc: ./hs.out 5.12s user 0.07s system 96% cpu 5.380 total gcc: ./a.out 5.58s user 0.00s system 97% cpu 5.710 total ghc: ./try 31.11s user 0.00s system 96% cpu 32.200 total As you can see, jhc shines at this example, actually beating gcc -O3. It isn't too surprising, this is exactly the sort of haskell code that jhc excels at. What's the property of that code which makes jhc excels in it? What makes ghc perform so poorly in comparison? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC vs GCC vs JHC
It's important to switch from mod to rem. This can be done by a simple abstract interpretation. I'm nore sure if it's jhc or gcc that does this for jhc. -- Lennart On Sat, Mar 27, 2010 at 10:30 PM, Rafael Cunha de Almeida almeida...@gmail.com wrote: John Meacham wrote: Here are jhc's timings for the same programs on my machine. gcc and ghc both used -O3 and jhc had its full standard optimizations turned on. jhc: ./hs.out 5.12s user 0.07s system 96% cpu 5.380 total gcc: ./a.out 5.58s user 0.00s system 97% cpu 5.710 total ghc: ./try 31.11s user 0.00s system 96% cpu 32.200 total As you can see, jhc shines at this example, actually beating gcc -O3. It isn't too surprising, this is exactly the sort of haskell code that jhc excels at. What's the property of that code which makes jhc excels in it? What makes ghc perform so poorly in comparison? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
2010/03/27 Leon Smith leon.p.sm...@gmail.com: I've heard rumors that in the early days of programming, that women were in the majority, or at least they represented a much greater proportion of programmers than they do now. I seem to recall that this started to change sometime in the 60s. Of course, I can't recall when or where I heard these stories, and I'm not sure that my source was reliable, so I might be completely off on this count. Women have been computers for a long time but they were not generally the majority or even very well represented. http://www.thenewatlantis.com/publications/the-age-of-female-computers In the Second World War, however, this changed; many, many women were brought into the computer corps and the first six programmers of the ENIAC, all women, were drawn from that corps. http://en.wikipedia.org/wiki/Human_computer So it may have happened that women started out as the majority of programmers and maintained that role for awhile; but as computing evolved more men came to desire the position. Of course, all the bosses were still men; they might prefer to hire other men. Coupled with conservative attitudes about women at work, programming would've become more and more hostile for women and maybe they were motivated to leave. A friend of mine, an engineer now in San Francisco, used to work in defense in Australia. The defense industry there is apparently as conservative as it is in the United States. There were alot of people around who felt that women needn't be in the work place or have jobs like mechatronic engineer. She was greatly motivated to leave. In the forties, where would she have gone? -- Jason Dusek ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC vs GCC vs JHC
Lennart Augustsson wrote: It's important to switch from mod to rem. This can be done by a simple abstract interpretation. I'm nore sure if it's jhc or gcc that does this for jhc. It's not just adding rem. Ghc still runs much slower using rem. It's only when switching to -fvia-C and using rem that ghc gets close to gcc speed (even though, still slower). Now jhc seems to get it fast right away. What's going on here? Is ghc backend wrose than using gcc as a backend (which is what via-C seems to accomplish)? Are there cases when one way is preferred over the other? What are the tradeoffs here? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Why is it so different between 6.12.1 and 6.10.4_1 ?
On Sat, 2010-03-27 at 04:28 -0700, zaxis wrote: Of course, you are wrong ! C is VERY important for almost every programmer in the world! Hmm. We don't deny that C is important. However importance of hammer does not make screwdriver unimportant. While you can say that you can use screwdriver like a hammer (like you can use Haskell to do imperative programming or vice versa) it is usually terribly inefficient and/or inelegant. Why cannot C programmer use haskell ? (S)He can. However (s)he have to redefine him/herself from being C programmer. As real programmer can program in Fortran in any language you can program in any language in Haskell. You just shouldn't (as you shouldn't program in X in Y for nearly any X != Y). And Why does haskell support C code style ? And BTW. Haskell have no 'C' style. You probably refer to do syntax sugar which is: - Not really C-style. It have syntax nowhere like C - Only partially in traditional imperative style as it do distinguish still between pure and unpure computation - It can be use for much more then crude C signature.asc Description: This is a digitally signed message part ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
Many of you may be interested in reading the Geek Feminism blog and wiki: http://geekfeminism.wikia.com/wiki/Geek_Feminism_Wiki http://geekfeminism.org/ It's not necessary to agree with everything, or to debate it, just try to put yourself in someone else's shoes. Friendly, --Lane ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC vs GCC vs JHC
On Sat, Mar 27, 2010 at 07:30:30PM -0300, Rafael Cunha de Almeida wrote: John Meacham wrote: Here are jhc's timings for the same programs on my machine. gcc and ghc both used -O3 and jhc had its full standard optimizations turned on. jhc: ./hs.out 5.12s user 0.07s system 96% cpu 5.380 total gcc: ./a.out 5.58s user 0.00s system 97% cpu 5.710 total ghc: ./try 31.11s user 0.00s system 96% cpu 32.200 total As you can see, jhc shines at this example, actually beating gcc -O3. It isn't too surprising, this is exactly the sort of haskell code that jhc excels at. I have not thoroughly checked it, but I think there are a couple things going on here: jhc is able to determine that all the arguments to the various functions are strict, so it can avoid all heap allocations and evaluations. ghc also benefits from this optimization. jhc sees that all the functions are fully applied to all their arguments, this means that they can always be directly called with optimized calling conventions as they will never have to represent generic 'eval' thunks or partial applications. it sees that all the functions are local to 'main' and not exported, so it can actually translate them to local functions in main in grin, allowing some more useful optimizations. Now the most important one, after optimizing the local functions, jhc sees that they are only called in tail-call position, so jhc is able to turn the function calls into direct jumps, turning them directly into C while/for loops operating fully on automatic variables on the stack. These last two optimizations are enabled by an incredibly useful extension to boquist's GRIN which is to allow a form of local function definitions, which solve a number of issues raised in his paper. Via a series of Grin-Grin transformations I am able to turn these local funciton definitions into direct conditional jumps in the resulting code. (which translate to looping constructs, if's and goto's in C) John -- John Meacham - ⑆repetae.net⑆john⑈ - http://notanumber.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC vs GCC
On 28/03/2010, at 01:36, Jan-Willem Maessen wrote: It's worth pointing out that there's a bit of bang-pattern mysticism going on in this conversation (which has not been uncommon of late!). A non-buggy strictness analyzer should expose the strictness of these functions without difficulty. Actually, rangeJ is lazy in i and rangeK is lazy in i and j. GHC does unbox everything important here but that needs more optimisations than just strictness analysis. You are right, though, that GHC doesn't need bang patterns here. Roman ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC vs GCC vs JHC
On 27/03/2010, at 05:27, John Meacham wrote: Here are jhc's timings for the same programs on my machine. gcc and ghc both used -O3 and jhc had its full standard optimizations turned on. jhc: ./hs.out 5.12s user 0.07s system 96% cpu 5.380 total gcc: ./a.out 5.58s user 0.00s system 97% cpu 5.710 total ghc: ./try 31.11s user 0.00s system 96% cpu 32.200 total I really don't understand these GHC numbers. I get about 3s for the C version, about 5s for GHC with rem and about 7.5s for GHC with mod. Is this perhaps on a 64-bit system? What is sizeof(int) in C and sizeOf (undefined :: Int) in Haskell? That said, I suspect the only thing this benchmark really measures is how fast the various compilers can compute i * i + j * j + k * k `mod` 7. Roman ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
One study suggests that the perceived work environment is too geeky: http://www.msnbc.msn.com/id/34437233/ns/technology_and_science-science/ I also suspect that much Haskell promotion is targeted towards male oriented sites, which does not help things: http://www.quantcast.com/slashdot.org http://www.quantcast.com/reddit.com So, basically, just cultural issues combined with 'poorly targeted' marketing. So, stop being so geeky ;) - jeremy 2010/3/27 Günther Schmidt gue.schm...@web.de Hi all, from the names of people on the list it seems that all users here are males. Just out of curiosity are there any female users here, or are we guys only at the moment? Günther ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC vs GCC vs JHC
On 28/03/2010, at 11:07, John Meacham wrote: I have not thoroughly checked it, but I think there are a couple things going on here: It could also be worthwhile to float out (i*i + j*j) in rangeK instead of computing it in every loop iteration. Neither ghc nor gcc can do this; if jhc can then that might explain the performance difference (although I would expect it to be larger in this case). Roman ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Why is it so different between 6.12.1 and 6.10.4_1 ?
I just mean syntax. For example. the following code snippet is C-style. In
vim, i can use `shift+%` to jump between `{' and `}', and so on.
hitSSQ hitNum = do {
nums - fmap str_ints_pick $ readFile ssqNum.txt;
forM_ nums (\n - do {
let { hitB = if (n!!6 == hitNum!!6) then 1 else 0 ;
hitR = foldl (\acc x - if(elem x (init hitNum)) then acc+1 else
acc) 0 (init n);};
printf %s\t%d:%d\t%s\n (show n) (hitR::Int) (hitB::Int) (hit_desc
hitR hitB);
});
}
Dietrich Epp-2 wrote:
I think Miljenovic was asking about this (I removed explicit braces):
fac n = let f = foldr (*) 1 [1..n] in f
Which is strictly equivalent to:
fac n = foldr (*) 1 [1..n]
Translated into C, this is kind of like doing this:
int add(int x, int y)
{
int sum = x + y;
return sum;
}
instead of this:
int add(int x, int y)
{
return x + y;
}
I find it very cumbersome (though not *difficult*) and painful to use
a C style of programming with Haskell, so I am not sure what you mean
when you ask why Haskell supports C style. Are you talking about
mutable state, syntax, or something else?
--Dietrich
On 2010 March 27, at 4:28, zaxis wrote:
Of course, you are wrong ! C is VERY important for almost every
programmer
in the world! Why cannot C programmer use haskell ? And Why does
haskell
support C code style ?
Ivan Miljenovic wrote:
zaxis z_a...@163.com writes:
Why do you bother with the interior definition of f in there?
Because i want to try a C code style not layout style without `do`
syntax
sugar .
Haskell /= C, so stop trying to code as if it is. If you like C so
much, then use C.
--
Ivan Lazar Miljenovic
ivan.miljeno...@gmail.com
IvanMiljenovic.wordpress.com
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Re: [Haskell-cafe] GHC vs GCC vs JHC
On 28/03/2010, at 09:47, Lennart Augustsson wrote: It's important to switch from mod to rem. This can be done by a simple abstract interpretation. Also, changing the definition of rem from a `rem` b | b == 0 = divZeroError | a == minBound b == (-1) = overflowError | otherwise = a `remInt` b to a `rem` b | b == 0 = divZeroError | b == (-1) a == minBound = overflowError | otherwise = a `remInt` b speeds up the GHC version by about 20%. Figuring out why is left as an exercise to the reader :-) Roman ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Why is it so different between 6.12.1 and 6.10.4_1 ?
thanks for your answer! However, i still feel the following code snippets
have different code style.
1. C-style
winSSQ count noRed noBlue = do {
let {yesRed=[1..33] \\ noRed; yesBlue=[1..16] \\ noBlue};
ps - picoSec;
setStdGen (mkStdGen $ fromInteger ps);
result - pick_ssq_nums count yesRed yesBlue [];
forM_ result (\x - print x);
writeFile ssqNum.txt $ ints_str result;
}
2. layout style
picoSec :: IO Integer
picoSec = do
t - ctPicosec `liftM` (getClockTime = toCalendarTime)
return t
The layout style makes me think of python.
Maciej Piechotka wrote:
On Sat, 2010-03-27 at 04:28 -0700, zaxis wrote:
Of course, you are wrong ! C is VERY important for almost every
programmer
in the world!
Hmm. We don't deny that C is important. However importance of hammer
does not make screwdriver unimportant.
While you can say that you can use screwdriver like a hammer (like you
can use Haskell to do imperative programming or vice versa) it is
usually terribly inefficient and/or inelegant.
Why cannot C programmer use haskell ?
(S)He can. However (s)he have to redefine him/herself from being C
programmer. As real programmer can program in Fortran in any language
you can program in any language in Haskell. You just shouldn't (as you
shouldn't program in X in Y for nearly any X != Y).
And Why does haskell
support C code style ?
And BTW. Haskell have no 'C' style. You probably refer to do syntax
sugar which is:
- Not really C-style. It have syntax nowhere like C
- Only partially in traditional imperative style as it do distinguish
still between pure and unpure computation
- It can be use for much more then crude C
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Re: [Haskell-cafe] Why is it so different between 6.12.1 and 6.10.4_1 ?
Both 6.10 and 6.12 use same .ghci !
%cat ~/.ghci
:cd /media/G/www/qachina/db/doc/money
:l Money
%cat Money.hs|grep import
import System( getArgs )
import System.Random
import System.IO
import System.Time
import Text.Printf (printf)
import Text.Regex
import Data.List
import Data.Time.Calendar
import Data.Time.Calendar.WeekDate
import Control.Monad
Sincerely!
Yusaku Hashimoto wrote:
Hmm, When a ghci was started, there should be the only loaded module
(Prelude.) And in both 6.10 and 6.12, such instance is not defined or
exported in its Prelude. So please try `ghci -ignore-dot-ghci`. It
invokes ghci without reading ~/.ghci and ./.ghci.
And `((-) a)` is known as the Reader Monad, `a` can be regarded as
the environment. My typical usage of that is like following:
import Control.Monad
data Vec = Vec { x :: Int, y :: Int }
absolute :: Vec - Double
absolute = sqrt . fromIntegral . liftM2 (+) (square . x) (square . y)
where
square a = a * a
The definition of `absolute` above can be rewritten as
absolute p = sqrt . fromIntegral $ square (x p) + square (y p)
where
square a = a * a
How `square . x` and `square . y` share the argument? Because `Monad
((-) a)` is defined as
instance Monad ((-) a) where
return x = \a - x
m = f = \a - f (m a) a
Note `(=)` propagates `a` into both of its arguments. That's why the
functions read same argument.
HTH
-nwn
On Sat, Mar 27, 2010 at 3:31 PM, zaxis z_a...@163.com wrote:
I just start ghci from shell and do nothing else. In fact, i really donot
know `Monad ((-) a) ` . Would you mind expplain it ?
Yusaku Hashimoto wrote:
Did you import the module includes the instance of Monad ((-) e)
somewhere in your code loaded in ghci?
I tried this on a fresh ghci 6.12, but I got No instance error.
-nwn
On Sat, Mar 27, 2010 at 9:20 AM, zaxis z_a...@163.com wrote:
In 6.12.1 under archlinux
let f x y z = x + y + z
:t f
f :: (Num a) = a - a - a - a
:t (=) . f
(=) . f :: (Num a) = a - ((a - a) - a - b) - a - b
((=) . f) 1 (\f x - f x) 2
5
In 6.10.4_1 under freebsd
let f x y z = x + y + z
*Money :t f
f :: (Num a) = a - a - a - a
:t (=) . f
(=) . f :: (Monad ((-) a), Num a) = a - ((a - a) - a - b) - a
- b
((=) . f) 1 (\f x - f x) 2
interactive:1:1:
No instance for (Monad ((-) a))
arising from a use of `=' at interactive:1:1-5
Possible fix: add an instance declaration for (Monad ((-) a))
In the first argument of `(.)', namely `(=)'
In the expression: ((=) . f) 1 (\ f x - f x) 2
In the definition of `it': it = ((=) . f) 1 (\ f x - f x) 2
Sincerely!
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Re: [Haskell-cafe] Internet game servers in Haskell?
On Sat, Mar 27, 2010 at 3:14 AM, Colin Paul Adams co...@colina.demon.co.ukwrote: Has anyone ever written a server in Haskell for managing live game-playing (any game) across the internet? I haven't yet, but I saw someone had a simple MUD-like game engine a few years ago. I don't know if Frag supports network play, but I would assume not. David Roundy (original author of Darcs) wrote something for bridge years ago, but I don't know if he wrote it in Haskell or if it's still available. If I had infinite free time it would be a fun project! Any particular reason why you're interested? Jason ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Haskell-friendly Linux Distribution
Hi, I am choosing a Linux distribution for a production Haskell project and would would normally just go with Debian (pedigree, stability, and of course Haskell Platfom included) but CentOS is in the frame. Are there any particularly strong reasons for preferring or avoiding any particular distribution? Chris --- Chris Dornan email : ch...@chrisdornan.com tel : +1 (847) 691 7945 ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell-friendly Linux Distribution
On Sat, Mar 27, 2010 at 11:11 PM, Chris Dornan ch...@chrisdornan.com wrote: Are there any particularly strong reasons for preferring or avoiding any particular distribution? A bunch of stuff is packaged by dons for Arch; you can see a lot of links to the Arch packages on Hackage. It might be worth looking into. -- Jeff Wheeler Undergraduate, Electrical Engineering University of Illinois at Urbana-Champaign ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell-friendly Linux Distribution
Jeff Wheeler j...@nokrev.com writes: On Sat, Mar 27, 2010 at 11:11 PM, Chris Dornan ch...@chrisdornan.com wrote: Are there any particularly strong reasons for preferring or avoiding any particular distribution? A bunch of stuff is packaged by dons for Arch; you can see a lot of links to the Arch packages on Hackage. It might be worth looking into. We may not have as many packages as Arch (because we don't just churn them willy-nilly) but Gentoo has a fair number of up-to-date Haskell packages in its overlay. -- Ivan Lazar Miljenovic ivan.miljeno...@gmail.com IvanMiljenovic.wordpress.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
