I am surprised that no one has mentioned David Sands' work yet in this
thread. He has studied this issue extensively in the nineties (setting
out from an analogous problem as the one given in Neil's original post).
There are a number of papers that came out of this. The one probably
most immediate
apfelmus wrote:
Note that using Peano-numbers can achieve the same effect of stopping
the length calculation as soon as more than one character is different.
data Nat = Zero | Succ Nat deriving (Eq, Ord)
instance Num Nat where
(Succ x) + y = Succ (x+y)
Zero+ y = y
Very nic
On Mon, Jun 04, 2007 at 09:43:32AM +0100, Alistair Bayley wrote:
> (The docs tell me that using GHC.Exts is the "approved" way of
> accessing GHC-specific extensions, but all of the useful stuff seems
> to be in GHC.Prim.)
All of the useful stuff *is* exported from GHC.Exts, it even says so in the
---
Haskell Weekly News
http://sequence.complete.org/hwn/20070723
Issue 63 - July 23, 2007
---
Welcome to issue 63 of HWN, a weekly newsletter covering
If you meant just non-graphic uses of a gpu, I don't know much in that
area, but I do know of a very neat graphics related (but irregular on
standard gpus) topic; ray tracing.
First off, a basic idea of what ray tracing is:
http://en.wikipedia.org/wiki/Ray_tracing
Second, for great reasons why
Michael,
I think what you're trying to do is perfectly doable in Haskell and I think
the right tool for it is arrows, as Tomasz Zielonka mentioned before. I
suggest you take a look at the following paper which uses arrows to enforce
security levels in the code:
http://www.cis.upenn.edu/~stevez/pa
Hello cafe,
(Following up on my own optimisation question, and Duncan's advice
to look at http://darcs.haskell.org/ghc/compiler/utils/Encoding.hs)
If you want to look at some existing optimised UTF8 encoding/decoding
code then take a look at the code used in GHC:
http://darcs.haskell.org/ghc/c
On Tue, 2007-03-20 at 15:09 +1000, Matthew Brecknell wrote:
> I'm not sure I see the problem, since any operation that touches all the
> elements of a n-by-n matrix will be at least O(n^2). For such an
> operation, a transposition should just add a constant factor.
What I was hoping for was a dat
Thanks for your response.
There 's one thing I don't understand however: the countRef function
returns the same MVar all the time.
What 's the reason for that ?I would expect that every time that
function is invoked, it returns a new MVar,
but clearly it does not.
From the documentati
It seems to me that the best answer, rather than constraining equational
reasoning, is to recognize what we're doing.
We start out with a specification for the program we're writing (this could be
a Haskell script for a previous version of the program, or just a set of
equations (or other prope
Haskell is known for its power at equational reasoning - being able
to treat a program like a set of theorems.
when you're trying to do equational reasoning, you better make
sure that you're reasoning with equations. as others have pointed
out some of the more interesting relations between prog
Note that you can take any closed term e and do the following
"equational reasoning":
e
==> let x = e in x
==> let x = x in x
==> _|_
Technically, though, this is not "wrong", in that it is still
"consistent", where consistency is defined using the usual information
ordering on domains. Conv
On Fri, 2007-07-20 at 13:47 +0400, Dmitri O.Kondratiev wrote:
>
> Oliver, thanks!
> I tried that, yet have some problems.
>
> Questions:
> 1) Should I ignore autoreconf errors?
I've never managed to get autoconf working on windows. I always generate
a tarball under linux and build that on Win
On Sun, 2007-07-22 at 18:02 +0400, Bulat Ziganshin wrote:
> Hello Neil,
>
> Saturday, July 21, 2007, 11:46:59 PM, you wrote:
> >> can anyone provide wxHaskell already compiled/compilable with ghc 6.6.1 on
> >> Windows?
>
> > This is precisely the reason I switched to Gtk2Hs - Duncan provides
> >
Here is another prime sieve. It is about half the length of the
fastest contributed code (ONeillPrimes) and nearly as fast until it
blows up on garbage collection:
% cat ONeillPrimes.hs | grep -v "^--" | wc
18511056306
% cat BayerPrimes.hs | grep -v "^--" | wc
85 566
Thomas Schilling wrote:
> On 22 jul 2007, at 23.46, Benjamin Franksen wrote:
>> On a different note: I've been wondering how difficult it would be to
>> re-write Parsec so that it doesn't act on a /list/ of tokens but on a
>> Sequence (defined in Data.Collections from collections package).
>> Bec
On 7/22/07, Andrew Coppin <[EMAIL PROTECTED]> wrote:
It seems everybody misunderstands what I mean by "production-grade".
Not at all. It's just that some of us are interested to know what part
Haskell might play in a production-grade renderer, where we mean
*production*-grade renderer.
--
Dan
On 22 jul 2007, at 23.46, Benjamin Franksen wrote:
On a different note: I've been wondering how difficult it would be to
re-write Parsec so that it doesn't act on a /list/ of tokens but on a
Sequence (defined in Data.Collections from collections package).
Because
this would mean one could use
On 7/22/07, Neil Mitchell <[EMAIL PROTECTED]> wrote:
However, if we use the rule that "anywhere we encounter span (not . g)
we can replace it with break g" then we can redefine break as:
break g = break g
For some reason this reminds me of the paradoxes of being able to go back in
time. Wha
Hi Neil
You'll be pleased to know that lots of people have been banging their
heads
off this one.
On 22 Jul 2007, at 15:53, Neil Mitchell wrote:
[..]
break g = span (not . g)
[..]
However, if we use the rule that "anywhere we encounter span (not . g)
we can replace it with break g" the
heh! well everyone was busy working on icfp or something, so the newsgroup
was pretty dead :-) And I played with opengl a little, which gave better
results than I thought, but not good enough to pursue, and the whole program
was in imperative "do"s anyway, so I couldnt quite see what was the poin
Re, Joseph (IT) wrote:
> Ah, I thought I might have to resort to one of the ByteStrings modules.
> I've heard of them but was more or less avoiding them due to some
> complexities with installing extra libraries in my current dev
> environment. I'll try to work that out with the sysadmins and try
Niko Korhonen wrote:
> Bryan Burgers wrote:
>> tpdfs range = do
>> g <- newStdGen -- get a random generator
>> (g1, g2) <- return $ split g -- make two random generators out of it
>> return $ zipWith combine (randomRs range g1) (randomRs range g2)
>> -- get two streams of random numbers,
Neil Mitchell wrote:
Hi
Haskell is known for its power at equational reasoning - being able to
treat a program like a set of theorems. For example:
break g = span (not . g)
Which means we can replace:
f = span (not . g)
with:
f = break g
by doing the opposite of inlining, and we still have
On Saturday 21 July 2007 01:41:58 Hugh Perkins wrote:
> Ok, that got the variables working.
> ...
Don't fizzle out on me now: this was just getting interesting! :-)
--
Dr Jon D Harrop, Flying Frog Consultancy Ltd.
OCaml for Scientists
http://www.ffconsultancy.com/products/ocaml_for_scientists/?e
Neil Mitchell wrote:
> Haskell is known for its power at equational reasoning - being able to
> treat a program like a set of theorems. For example:
>
> break g = span (not . g)
>
> Which means we can replace:
>
> f = span (not . g)
>
> with:
>
> f = break g
>
> by doing the opposite of inlin
Hi
Haskell is known for its power at equational reasoning - being able to
treat a program like a set of theorems. For example:
break g = span (not . g)
Which means we can replace:
f = span (not . g)
with:
f = break g
by doing the opposite of inlining, and we still have a valid program.
How
Dan Piponi wrote:
On 7/14/07, Andrew Coppin <[EMAIL PROTECTED]> wrote:
The "Haskell ray tracer" seems to be a pretty standard and widely-used
example program. But has anybody ever seriously tried to make a
"production-grade" implementation? (I.e., one that is user-friendly,
efficient, and with l
Donald Bruce Stewart wrote:
Yeah, there's some known low level issues in the code generator
regarding heap and stack checks inside loops, and the use of registers
on x86.
But note this updated paper,
http://www.cse.unsw.edu.au/~chak/papers/CLPKM07.html
Add another core to your machine and i
> Please try the darcs version
> darcs get http://darcs.haskell.org/wxhaskell
thanks. should i follow building instructions from homepage/ directory
or there are another one?
I don't remember if this is documented anywhere, sadly:
It's
./configure
make
make install
make wx
make wx-install
Hello Eric,
Saturday, July 21, 2007, 9:29:30 AM, you wrote:
>> can anyone provide wxHaskell already compiled/compilable with ghc 6.6.1 on
>> Windows?
> Please try the darcs version
> darcs get http://darcs.haskell.org/wxhaskell
thanks. should i follow building instructions from homepage/ direc
Hello Neil,
Saturday, July 21, 2007, 11:46:59 PM, you wrote:
>> can anyone provide wxHaskell already compiled/compilable with ghc 6.6.1 on
>> Windows?
> This is precisely the reason I switched to Gtk2Hs - Duncan provides
> Windows installers as each new GHC release comes out. If wxHaskell
> wants
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