On 23 February 2011 05:31, Johan Tibell johan.tib...@gmail.com wrote:
Can someone come up with a real world example where O(1) size is important?
Tangentially - if you changed the API so the size function was called
'count' rather than 'size' or 'length', there would be no shame what's
so ever
On 23 February 2011 05:31, Johan Tibell johan.tib...@gmail.com wrote:
On Tue, Feb 22, 2011 at 9:19 PM, Johan Tibell johan.tib...@gmail.com wrote:
Initial numbers suggest that lookup gets 3% slower and insert/delete
6% slower. The upside is O(1) size.
Can someone come up with a real world
I am using mtl-2. Importing Control.Monad.Error doesn't work, I have
to explicitly import Control.Monad.Instances.
2011/2/22 Daniel Fischer daniel.is.fisc...@googlemail.com:
On Tuesday 22 February 2011 23:07:05, Yves Parès wrote:
Hello,
When importing Control.Monad.Error, it shows me that
On 23 February 2011 06:47, bri...@aracnet.com wrote:
Hi all,
I'm working on an FFI and as usual there are lots of defines in
the header files.
What's the best way to make these available to the haskell code ?
Ideally it could be done automagically, or at least pseudo-magically so
that
I took a rapid look and they seem a replacement for pure Map's, but not for
mutable HashTable's. Sorry if it isn't the case. I don´t know if
Data.HashTable has improved, but the performance used to be very poor in
comparison with other languages.
The point is that pure data structures can not be
Thanks John,
The simple answer is that I need to be able to use HDBC in proprietary
products and the LGPL makes this awkward - the most serious issue being that
owners of the code base don't want GNU licensed parts being linked into
their code base. Packaging and delivery also gets
On Wed, Feb 23, 2011 at 12:30 PM, Alberto G. Corona agocor...@gmail.com wrote:
For this reason I think that an inprovement/mutable-replacement of
Data.HashTable is needed. If this hasn´t been done already. Are there
some improvements on it that I don't know?
I've been working on one lately,
Johan Tibell wrote:
I'm working on a patch that provides O(1) size right now. The trick is
to define HashMap as:
data HashMap k v = HM {-# UNPACK #-} !Int !(Tree k v)
Another possibility is:
data HashMap k v = HM Int !(Tree k v)
hashMap t = HM (treeSize t) t
That way size is O(n) on first
On Wednesday 23 February 2011 09:58:56, Yves Parès wrote:
I am using mtl-2. Importing Control.Monad.Error doesn't work, I have
to explicitly import Control.Monad.Instances.
Weird. Control.Monad.Error imports Control.Monad.Instances (), so it ought
to be visible.
What exact versions of mtl,
On Sat, Feb 19, 2011 at 4:38 AM, Johan Tibell johan.tib...@gmail.com wrote:
Hi all,
I am delighted to announce the release of preview versions of two new
packages:
unordered-containers 0.1
Efficient hashing-based container types.
http://hackage.haskell.org/package/unordered-containers
The latest, I think :
GHC 7.0.1,
mtl-2.0.1.0,
base-4.3.0.0
2011/2/23 Daniel Fischer daniel.is.fisc...@googlemail.com:
On Wednesday 23 February 2011 09:58:56, Yves Parès wrote:
I am using mtl-2. Importing Control.Monad.Error doesn't work, I have
to explicitly import Control.Monad.Instances.
On Wednesday 23 February 2011 14:14:46, Yves Parès wrote:
The latest, I think :
GHC 7.0.1,
mtl-2.0.1.0,
base-4.3.0.0
Hmm, that's exactly what I have. Weirder and weirder.
For the moment, I'm out of ideas.
___
Haskell-Cafe mailing list
2011-02-23 13:56, Victor Nazarov skrev:
Also I think that value of hash functions is obviously a Monoid and it
will be convenient to have Monoid instance
newtype Hash = Hash Int
instance Monoid Hash where
mempty = Hash 0
Hash a `mappend` Hash b = Hash (a `combine` b)
Just write a loop:
let loop gs gu
| Just z - find_obj gu usyms = do
...
(gs', gu') - handle_obj_ar ...
loop gs' gu'
| otherwise = return (gs,gu)
(gs, gu) - loop def undef
mfix is for when you have mutually recursive data but you want the IO
operation
Antoine Latter wrote:
As the error says, compiling with the flag '-XFlexibleInstances' will
make the message go away.
You can also add a language pragma to the top of your source file:
{-# LANGUAGE FlexibleInstances #-}
Antoine
When I enable that flag, I then also have to enable
On 23 February 2011 12:05, Gregory Collins g...@gregorycollins.net wrote:
I've been working on one lately, some preliminary benchmarks:
https://gist.github.com/826935
It's probably a month or two away from a releasable state, but my
work-in-progress is substantially faster (4-6X) than
On Wed, Feb 23, 2011 at 3:49 PM, Max Bolingbroke
batterseapo...@hotmail.com wrote:
On 23 February 2011 12:05, Gregory Collins g...@gregorycollins.net wrote:
I've been working on one lately, some preliminary benchmarks:
https://gist.github.com/826935
It's probably a month or two away from
On Wed, Feb 23, 2011 at 8:48 AM, Volker Wysk p...@volker-wysk.de wrote:
Hello
I'm new to Cabal, and I'm trying to Cabalize my library HsShellScript, with
help by Howard Golden. I'm using the Simple Build Infrastructure.
1. I'm irritated by the fact, that calling the Cabal with runhaskell
On Wed, 2011-02-23 at 08:42 -0600, Kurt Stutsman wrote:
When I was reviewing the Haskell language specification on haskell.org,
it certainly looked like what I was doing was supported by the language.
I found some comments on GHC's site about the reasoning behind these
flags, but I couldn't
On Wednesday 23 February 2011 15:42:46, Kurt Stutsman wrote:
Antoine Latter wrote:
As the error says, compiling with the flag '-XFlexibleInstances' will
make the message go away.
You can also add a language pragma to the top of your source file:
{-# LANGUAGE FlexibleInstances #-}
Daniel Fischer wrote:
No, it's not. The language report says an instance head must have the form
(tyCon a1 ... an),
where tyCon is a type constructor and a1 ... an are *distinct* type
variables (appropriate in number so that the head has the correct kind).
In instance (Enum e) = Test e
On 23 February 2011 15:40, Kurt Stutsman kstuts...@gmail.com wrote:
instance Enum e = Serializable e where
get mask = {- convert mask to Int and then to a BitSet -}
put bitset = {- convert BitSet to Int and then to String -}
I looks like all you need is for objects to be enumerable, i.e
This seems a timely email, as I've been submitting a steady-ish
trickle of patches to HDBC-postgresql lately. Honestly, I'm rather
dissatisfied with HDBC in many respects, but I don't have a very
good idea of what a (low-level) database access library for Haskell
*should* be, and I've found
Thanks for the examples. Point 3 is interesting but most of the gain
there could probably be had by telling the user to use (bigmap `union`
smallmap). My guess is that the user has a good idea which argument is
larger/smaller.
On Wed, Feb 23, 2011 at 12:45 AM, Max Bolingbroke
On Wed, Feb 23, 2011 at 3:30 AM, Alberto G. Corona agocor...@gmail.com wrote:
The point is that pure data structures can not be used as shared data in
multithreaded environments. They must be encapsulated in mutable blocking
references, such is MVars, and the whole update process blocks any
Hello! Thank you for your interest.
Daryoush Mehrtash dmehrt...@gmail.com wrote in haskell-cafe:
Is the Embedded domain-specific language HANSEI for probabilistic models
and (nested) inference described in:
http://okmij.org/ftp/kakuritu/index.html#implementation available in
Haskell?
The
Hi,
On 02/23/2011 04:40 PM, Kurt Stutsman wrote:
[...]
Test is actually a kind of Serializable class. I don't want to
restrict it to only working with Enums, which is what your
OverlappingInstances seems to address. Is there a better way for doing
what I am trying to do?
Example:
import
On Wed, Feb 23, 2011 at 4:56 AM, Victor Nazarov
asviraspossi...@gmail.com wrote:
What about making Hashable subclass of Eq
class Eq a = Hashable a where
I think it's is obvious from Hasable class properties that some kind
of equality is needed and I think it will reduce type class
Stephen Tetley wrote:
On 23 February 2011 15:40, Kurt Stutsman kstuts...@gmail.com wrote:
instance Enum e = Serializable e where
get mask = {- convert mask to Int and then to a BitSet -}
put bitset = {- convert BitSet to Int and then to String -}
I looks like all you need is for
On 02/23/2011 10:03 AM, Leon Smith wrote:
My biggest (mostly) fixable complaint with HDBC is that it hasn't
turned out to be a very complete or robust solution for accessing
databases that like to use PostgreSQL-specific features. My biggest
This is probably true, both that it isn't designed
On 02/23/2011 05:48 AM, Chris Dornan wrote:
The simple answer is that I need to be able to use HDBC in proprietary
products and the LGPL makes this awkward – the most serious issue being
that owners of the code base don’t want GNU licensed parts being linked
into their code base. Packaging and
From Kurt Stutsman kstuts...@gmail.com on Wed, February 23, 2011 9:40:09 AM
Daniel Fischer wrote:
No, it's not. The language report says an instance head must have the form
(tyCon a1 ... an),
where tyCon is a type constructor and a1 ... an are *distinct* type
variables
Thanks John,
I think this is a valuable discussion.
The compromise you propose wouldn't address the main point - the fear and
aversion of using (L)GPL IP in proprietary IP.
For me the key phrase in your email was the final one - 'if my reading is
correct'. Everywhere I would take
On Wed, Feb 23, 2011 at 11:08 AM, Johan Tibell johan.tib...@gmail.com wrote:
...
HashTable is not a concurrent data structure. You need e.g. a lock
free mutable hash table.
Good implementations of which are *not* thick on the ground. Even
java.util.concurrent isn't fully lock-free.
-Jan
On 02/23/2011 11:57 AM, Chris Dornan wrote:
Thanks John,
I think this is a valuable discussion.
The compromise you propose wouldn’t address the main point – the fear
and aversion of using (L)GPL IP in proprietary IP.
Is that fear well-grounded or not? If not, then people should be
On 23 February 2011 16:03, Johan Tibell johan.tib...@gmail.com wrote:
Thanks for the examples. Point 3 is interesting but most of the gain
there could probably be had by telling the user to use (bigmap `union`
smallmap). My guess is that the user has a good idea which argument is
John,
As far as I know it is the libraries that interface to O/S libraries that
have most value in the platform and, AFAIK, many HP libraries link to O/S
libraries (e.g., GLUT).
I had expected that at least the principle HDBC drivers would have to go
into the Haskell Platform with HDBC.
On Wed, Feb 23, 2011 at 12:46 PM, Max Bolingbroke
batterseapo...@hotmail.com wrote:
By the way, do you plan to add a HashSet to complement HashMap?
Yes, definitely. I want to flesh out the HashMap API some more and
then add a HashSet implementation. The code is still moving around a
lot (e.g.
On Wed, Feb 23, 2011 at 12:57 PM, Gwern Branwen gwe...@gmail.com wrote:
On Wed, Feb 23, 2011 at 12:45 AM, Max Bolingbroke
batterseapo...@hotmail.com wrote:
I'm a bit sceptical that it is (I was not convinced by the earlier
strict-set-inclusion argument, since that's another Data.Map feature
On Wed, Feb 23, 2011 at 1:18 PM, Johan Tibell johan.tib...@gmail.com wrote:
Could you manually look at some of them to see if you find something
interesting. In particular `Set.size s == 0` (a common use of size in
imperative languages) could be replaced by `Set.null s`.
You could look at
On Wed, Feb 23, 2011 at 1:27 PM, Gwern Branwen gwe...@gmail.com wrote:
You could look at them yourself; I attached the files. I see 6 uses
out of ~100 which involve an == 0
Looks like the mailing list gateway didn't let your attachements
through. No need to attach them though, I can just grep
A quick grep of some of my own source reveals that I've used M.size and S.size
only to test for sizes equal to 1. So, for my purposes at least, an O(1)
isSingleton operation would be just as useful as an O(1) size.
Cheers,
Sterl
On Feb 23, 2011, at 4:32 PM, Johan Tibell wrote:
On Wed, Feb
I would very much appreciate if you can expand on this:
Haskell's laziness doesn't help -- in fact, to avoid running out of
memory, we'd have to defeat that memoization by sprinkling () -
throughout the types.
Would it be possible to explain this with an example?
Thanks
Daryoush
On Wed,
On 23 February 2011 21:27, Gwern Branwen gwe...@gmail.com wrote:
On Wed, Feb 23, 2011 at 1:18 PM, Johan Tibell johan.tib...@gmail.com wrote:
Could you manually look at some of them to see if you find something
interesting. In particular `Set.size s == 0` (a common use of size in
imperative
On Wed, Feb 23, 2011 at 1:55 PM, Max Bolingbroke
batterseapo...@hotmail.com wrote:
Thanks for bringing some data to the table. There are definitely some
common patterns in what you sent me:
1) For defining Binary instances, you need to write set size before
you write the elements: ~7
Attached are all the uses of S.size and Set.size from a semi-recent
snapshot of Hackage.
Johan
Combinatorrent/0.3.2/Combinatorrent-0.3.2/src/Process/Peer.hs:let sz =
S.size q
Combinatorrent/0.3.2/Combinatorrent-0.3.2/src/Process/PieceMgr.hs:
ipHave = S.size . ipHaveBlocks
Roel van Dijk schrieb:
In general code compiled with GHC will be a lot faster than code
interpreted by GHCI. You can also call compiled code from within GHCI,
in which case you would hardly see a performance difference.
$ ghci -fobject-code
compiles modules before loading into the interpreter
On 2/23/11 4:42 PM, Sterling Clover wrote:
A quick grep of some of my own source reveals that I've used M.size and S.size
only to test for sizes equal to 1. So, for my purposes at least, an O(1)
isSingleton operation would be just as useful as an O(1) size.
I agree, a fast isSingleton
On Wed, Feb 23, 2011 at 10:52 AM, Chung-chieh Shan
ccs...@cs.rutgers.edu wrote:
Mostly we preferred (as do the domain experts we target) to write
probabilistic models in direct style rather than monadic style.
Haskell's laziness doesn't help -- in fact, to avoid running out of
memory, we'd
Welcome to issue 170 of the HWN, a newsletter covering developments in
the [1]Haskell community. This release covers the week of February 13 -
19, 2011.
Announcements
Simon Michael [2]informed us of reviving of FunGEn as a community
project. FunGEn (Functional Game Engine) is a
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