The challenge was the implement the modcount algorithm not to calculate
primes per se.
(see e.g. http://jjinux.blogspot.com/2005/11/io-comparison.html).
-Alex-
Donald Bruce Stewart wrote:
alex:
This implementation of calculating 1 primes (compiled with GHC -O2)
is 25% slower than the
Thought perhaps the problem is that modcount is just a slower algorithm.
... nevermind. Thanks.
-Alex-
Alex Jacobson wrote:
The challenge was the implement the modcount algorithm not to calculate
primes per se.
(see e.g. http://jjinux.blogspot.com/2005/11/io-comparison.html).
-Alex-
Alex:
The challenge was the implement the modcount algorithm not to calculate
primes per se.
(see e.g. http://jjinux.blogspot.com/2005/11/io-comparison.html).
Can you show us the Python code?
Paulo
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Frank Buss wrote:
I've created a small program to compose images with combinators:
http://www.frank-buss.de/haskell/OlympicRings.hs.txt
Finally, what do you think about using this concept for generating
images? It has some advantages, e.g. it is possible to scale the
image without quality
Marc Weber wrote:
On Sun, Aug 05, 2007 at 03:19:25PM -0700, David Pollak wrote:
Howdy,
As I'm starting to learn the Haskell libraries, I'm having a less than
fun time trying to figure out what functions operate on what types.
For example, in the documentation for HaXml, there's a
On 05/08/07, Frank Buss [EMAIL PROTECTED] wrote:
Is it possible to write functions with an arbitrary number of
arguments?
Would be nice if the average function would accept any number of pixel
values.
You may be interested to see Oleg Kiselyov's discussion on
polyvariadic functions in
Why not just:
primes = sieve [2..]
sieve (p : xs) = p : sieve [x | x - xs, x `mod` p 0]
main = print (take 1000 primes)
I am unable to see how exactly this will run. Given that primes is an infinite
list, and that when it reaches numbers say, as large as
There's a neat Haskell solution to the knapsack problem which runs very
fast. I'm not 100% sure that it runs faster than an optimal solution in
other GC'd imperative languages, but it's very concise and not (too)
convoluted. Have a search for the thread with xkcd in the title.
Chung-chieh Shan
On 8/6/07, Vimal [EMAIL PROTECTED] wrote:
I am unable to see how exactly this will run. Given that primes is an infinite
list, and that when it reaches numbers say, as large as 1, it will have to
keep track of all the numbers (essentially prime numbers, which is the
answer),
whose
Isn't it how it runs ? :
2: sieve [3,5,7,9,11,13,15,17,19,21,23,25,27,29,31,33,35,37,39,41,43,45,
47,49,... ]
then
2:3:sieve [5,7,11,13,17,19,23,25,29,31,35,37,41,43,47,49,... ]
then
2:3:5:sieve [7,11,13,17,19,23,29,31,37,41,43,47,49,... ]
then
2:3:5:7:sieve
primes n = sieve (take n [2..])
sieve (p:xs) = p : sieve [x | x - xs, x `mod` p 0]
print (primes 1000)
-- Vimal
But as we can see, this obviously doesn't *take* 1000 primes,
:-)
-- Vimal
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On Sat, 2007-08-04 at 23:59 +0100, Magnus Therning wrote:
I can't seem to find any information on how to deal with C functions
that return a (pointer to a) struct. C2hs tells me there's no automatic
support for marshalling structs (I'm using version 0.14.5).
If I'm to do it by hand, is
Hi
a) use hoogle (haskell.org/hoogle). You can use hoogle to find functions by
types. But I don't
know haw to create a query such as ... - Document - ...
Hoogle unfortunately doesn't do that very well, although that would be a
great feature.
Wait for version 4 :-) - I've added _ 's for
Vimal wrote:
Why not just:
primes = sieve [2..]
sieve (p : xs) = p : sieve [x | x - xs, x `mod` p 0]
main = print (take 1000 primes)
I am unable to see how exactly this will run. Given that primes is an infinite
list, and that when it reaches numbers say, as
Paulo Tanimoto wrote:
The challenge was the implement the modcount algorithm not to calculate
primes per se.
(see e.g. http://jjinux.blogspot.com/2005/11/io-comparison.html).
Can you show us the Python code?
Note this is python for the naive, accumulate and do modulus version.
Not for
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Hi,
I wrote a brute-force sudoku solver. It takes a [[Int]] and spits out
the first solution it finds.
Why is it, that
[0,0,0,7,0,6,9,0,0]
[9,0,0,0,0,4,7,0,0]
[7,0,0,0,0,0,4,0,0]
[0,2,7,0,3,5,8,0,0]
[6,9,5,8,2,0,0,0,0]
[0,8,0,0,0,0,5,0,0]
Thomas Conway wrote:
On 8/2/07, apfelmus [EMAIL PROTECTED] wrote:
That concludes the infinite terrain generation for one dimension. For
higher dimension, one just needs to use 2D objects instead of intervals
to split into two or more pieces. For instance, one can divide
equilateral triangles
=
Call for Participation
The 12th ACM SIGPLAN International Conference
on Functional Programming (ICFP 2007)
http://www.informatik.uni-bonn.de/~ralf/icfp07.html
In de book Modern C++ design, Andrei Alexandrescu writes that Haskell
supports “multi-methods”
http://books.google.com/books?id=aJ1av7UFBPwCpg=PA3ots=YPiJ_nWi6Ydq=moder
n+C%2B%2Bsig=FWO6SVfIrgtCWifj9yYHj3bnplQ#PPA263,M1
How is this actually done in Haskell? Maybe this is just a basic feature of
Original Message
Subject:PADL 2008: Call for Papers
Date: Sat, 4 Aug 2007 19:25:58 -0500 (CDT)
From: Gopal Gupta [EMAIL PROTECTED]
[ Colleagues, note that this will be the 10th PADL;
We strongly urge you to submit papers, the deadline is
only 3 weeks way]
peterv wrote:
In de book Modern C++ design, Andrei Alexandrescu writes that Haskell
supports “multi-methods”
Using multi-methods, I could write (in pseudo code)
collide (Asteroid, Planet) = an asteroid hit a planet
collide (Asteroid, Earth) = the end of the dinos
...
collide (Planet,
Remember that type classes do not provide object-oriented functionality.
The dispatch is static, not dynamic. Although OOP can be simulated in
Haskell, it is not a natural idiom. If you need dynamic dispatch
(including multiple dispatch), you may want to reconsider your solution.
Dan Weston
peterv schrieb:
In de book Modern C++ design, Andrei Alexandrescu writes that Haskell
supports “multi-methods”
http://books.google.com/books?id=aJ1av7UFBPwCpg=PA3ots=YPiJ_nWi6Ydq=moder
n+C%2B%2Bsig=FWO6SVfIrgtCWifj9yYHj3bnplQ#PPA263,M1
Chapter 11, Page 263 of this books:
The C++ virtual
Dan Weston wrote:
Remember that type classes do not provide object-oriented
functionality. The dispatch is static, not dynamic. Although OOP can
be simulated in Haskell, it is not a natural idiom. If you need
dynamic dispatch (including multiple dispatch), you may want to
reconsider your
Remember that type classes do not provide object-oriented functionality.
The dispatch is static, not dynamic.
I beg to disagree.
map (\n. n + n)
calls different (+) operations depending on the (type of the) argument list.
That's why dictionaries are passed around (they are called vtables
Am Montag, 6. August 2007 00:48 schrieb Frank Buss:
I've created a small program to compose images with combinators:
http://www.frank-buss.de/haskell/OlympicRings.hs.txt
...
look very smooth. And it is very slow, it needs about 40 seconds on my
computer to calculate the image. Using
Hi all,
I'm starting to learn haskell by my own, being currently mostly a
Common Lisp, Scheme, C++ programmer... I've got the haskell emacs mode
but can't find a manual. Moreover, I've found some keybindings on the
net but nothing that allows me to start an interpreter in emacs and
send
On 6 aug 2007, at 22.11, Paulo J. Matos wrote:
Hi all,
I'm starting to learn haskell by my own, being currently mostly a
Common Lisp, Scheme, C++ programmer... I've got the haskell emacs mode
but can't find a manual. Moreover, I've found some keybindings on the
net but nothing that allows me
This is very nice, but it does not really solve the original problem.
In your code, evaluating
collide (Jupiter, Asteroid)
will result in an endless loop. This is expected in your code, because no
inheritance relation is present between e.g Jupiter and Planet. With
multi-dispatch, it should
C-c C-b ... when pressed for the first time this will start an
interpreter (ghci or hugs most of the time), when pressed with a
running interpreter it'll switch to that buffer.
C-c C-l ... Load the current file into the editor. There is no
function-wise compilation.
Don't forget C-c
Thomas Schilling wrote:
On 6 aug 2007, at 22.11, Paulo J. Matos wrote:
If you're used to Slime+Paredit, then there isn't something really
comparable, but you get some basic interactive programming with the
standard key-bindings:
(But paredit does work in haskell-mode, and I find it
Does anyone know of a fairly complete Java 1.5 parser and abstract syntax in
Haskell?
I've looked around quite a bit to no avail.
Thanks,
- Tim
--
View this message in context:
http://www.nabble.com/Java-1.5-parser-in-Haskell-tf4227017.html#a12025365
Sent from the Haskell - Haskell-Cafe mailing
Note that the official way to solve sudoku is to use dancing links, but
I guess you are creating a naive implementation precisely as a base-line
against which to measure other implementations?
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Most examples for defining algebraic types include data constructors like so:
data Tree a = Tip | Node a (Tree a) (Tree a)
I by mistake defined a type which did not specify a data constructor :
data SearchCondition = Term Bool | SearchCondition :||: (Term Bool)
data Term a = Constant a
sc ::
Hi
I by mistake defined a type which did not specify a data constructor
So the question is what are types with no constructors good for? A
simple example would be appreciated.
They are called phantom types, and can be used for ensuring properties
at the type level.
I wrote about them in a
The answer would be phantom types, but your example doesn't use them.
Each of your types has at least one constructor:
Possibly you overlooked the infix constructor :||: ?
Tree a has 2 constructors: Tip and Node
SearchCondition has 2 constructors: Term and (:||:)
Term a has
On Monday 06 August 2007 19:23, Rahul Kapoor wrote:
Most examples for defining algebraic types include data constructors like
so:
data Tree a = Tip | Node a (Tree a) (Tree a)
I by mistake defined a type which did not specify a data constructor :
In this example, you have two different uses
On 2007-08-06, Rahul Kapoor [EMAIL PROTECTED] wrote:
I by mistake defined a type which did not specify a data constructor :
No, you didn't. Both types have data constructors.
data SearchCondition = Term Bool | SearchCondition :||: (Term Bool)
data Term a = Constant a
sc :: SearchCondition
Constructors and names of data types live in separate namespaces.
The above fact was the cause of all my confusion. It just slipped out
of my mind.
Cheers,
Rahul
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Hi,
Am Montag, 6. August 2007 15:07 schrieb Adrian Neumann:
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Hi,
I wrote a brute-force sudoku solver. It takes a [[Int]] and spits out
the first solution it finds.
Why is it, that
[0,0,0,7,0,6,9,0,0]
[9,0,0,0,0,4,7,0,0]
I know this isn't quite what you asked, but java has a very clearly
laid-out grammar in EBNF at
http://java.sun.com/docs/books/jls/first_edition/html/19.doc.html .
Between that and Parsec, I would think it would be fairly simple to
write a parser. Of course, adding semantics is another story.
On
On 8/7/07, Hugh Perkins [EMAIL PROTECTED] wrote:
Note that the official way to solve sudoku is to use dancing links, but
I guess you are creating a naive implementation precisely as a base-line
against which to measure other implementations?
Well, Dancing Links (DLX) is just a data structure +
j.vimal:
On 8/7/07, Hugh Perkins [EMAIL PROTECTED] wrote:
Note that the official way to solve sudoku is to use dancing links, but
I guess you are creating a naive implementation precisely as a base-line
against which to measure other implementations?
Well, Dancing Links (DLX) is just a
On 8/7/07, Donald Bruce Stewart [EMAIL PROTECTED] wrote:
See also,
http://haskell.org/haskellwiki/Sudoku
-- Don
Just out of ... errr curiosity... which of those implementations is the
fastest?
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hughperkins:
On 8/7/07, Donald Bruce Stewart [EMAIL PROTECTED]
wrote:
See also,
[2]http://haskell.org/haskellwiki/Sudoku
-- Don
Just out of ... errr curiosity... which of those
implementations is the fastest?
No idea. You could compile them all
I am having problems coming up with nice combinators for a simple
DSEL. The abstract syntax is simply given by the types:
data SearchCondition = SearchCondition BoolTerm | OpOr SearchCondition BoolTerm
data BoolTerm = BoolTerm BoolFactor | OpAnd BoolTerm BoolFactor
data BoolFactor = Constant
On Mon, Aug 06, 2007 at 10:33:01PM -0400, Rahul Kapoor wrote:
I am having problems coming up with nice combinators for a simple
DSEL. The abstract syntax is simply given by the types:
data SearchCondition = SearchCondition BoolTerm | OpOr SearchCondition
BoolTerm
data BoolTerm =
On Monday 06 August 2007, Rahul Kapoor wrote:
I am having problems coming up with nice combinators for a simple
DSEL. The abstract syntax is simply given by the types:
snip
Or is it a better idea to just remove the precedence rules from the
types and move it the part of the code that
apfelmus wrote:
The idea of representing images simply by a function
Int - Int - RGB
is great :) You may want to look at Pan and its various
offsprings, in
particular Pancito
http://www.haskell.org/haskellwiki/Applications_and_libraries/
Graphics#Pan
this looks interesting.
Marc A. Ziegert wrote:
in that source file, you define Size and Pixel as structs of
Integers. that are neither unsigned chars (8_bit) nor ints
(32-64_bit) nor floats (32_bit) but an artificial oo_bit int
(1 int + list of bytes).
i'm sure you will gain a speedup by redefining these
Hi,
I'm pondering, is it possible to define a Set monad analogous to the
List monad?
My thinking is as follows:
* fmap f x would apply f to each element in a set x
* return x would create a singleton set {x}
* join x, where x is a set of sets: x = {x1, x2, ... xn},
would form
On 8/7/07, Donald Bruce Stewart [EMAIL PROTECTED] wrote:
No idea. You could compile them all with -O2, run them on a set of
puzzles, and produce a table of results :-)
Well I could, but I wont ;-) If you had to guess which one is fastest which
one would you guess?
I'm a little surprised no
Ronald Guida:
I'm pondering, is it possible to define a Set monad analogous to the
List monad?
[snip]
This leads me think of a different solution: What if I could define a
Set monad that's smart enough to know, for any type a, whether or
not (Eq a) holds, and degenerate to a blind list if
peterv wrote:
This is very nice, but it does not really solve the original problem.
To get Haskell to choose the best fit it's necessary to encode the
location of each element in the hierarchy, so that elements deeper in
the hierarchy are more instantiated than those at the top. Then
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