Re: [Haskell-cafe] Computing the memory footprint of a HashMap ByteString Int (Was: How on Earth Do You Reason about Space?)

On Thu, Jun 2, 2011 at 5:10 AM, Jason Dagit wrote: > One of the cool things about SO is that you can answer your own > question.  For example, you might do that if you're anticipating an > FAQ.  I think asking this question on SO and reposting your answer > from this thread would be great. Good t

[Haskell-cafe] Haskell Weekly News: Issue 184

Welcome to issue 184 of the HWN, a newsletter covering developments in the Haskell community. This release covers the week of May 22 to 28, 2011. Announcements The newsletter has not been posting new library announcements, but Ivan Lazar's announcement of his new wl-pprint-text librar

Re: [Haskell-cafe] Computing the memory footprint of a HashMap ByteString Int (Was: How on Earth Do You Reason about Space?)

On Wed, Jun 1, 2011 at 8:33 AM, Johan Tibell wrote: > On Wed, Jun 1, 2011 at 4:24 PM, Aleksandar Dimitrov > wrote: >> One additional thought: it might be interesting to provide this outside of >> this >> mailing list, perhaps as a documentation addendum to unordered-containers, >> since >> it r

Re: [Haskell-cafe] *GROUP HUG*

On 11-06-01 07:15 PM, Don Stewart wrote: http://stackoverflow.com/questions/6172004/writing-foldl-using-foldr/6172270#6172270 Thank Graham Hutton and Richard Bird. Another one along the same line: http://www.vex.net/~trebla/haskell/natprim.xhtml Yet one more, along the tangent: http://www.v

Re: [Haskell-cafe] *GROUP HUG*

http://stackoverflow.com/questions/6172004/writing-foldl-using-foldr/6172270#6172270 Thank Graham Hutton and Richard Bird. On Wed, Jun 1, 2011 at 7:12 PM, Tom Murphy wrote: >> >> How about this: >> >> myFoldr :: (a -> b -> b) -> b -> [a] -> b >> myFoldr f z xs = foldl' (\s x v -> s (x `f` v)) id

Re: [Haskell-cafe] *GROUP HUG*

> > How about this: > > myFoldr :: (a -> b -> b) -> b -> [a] -> b > myFoldr f z xs = foldl' (\s x v -> s (x `f` v)) id xs $ z > > Cheers, > Ivan > Great! Now I really can say "Come on! It's fun! I can write foldr with foldl!" ___ Haskell-Cafe mailing l

[Haskell-cafe] [iteratee] how to do nothing .. properly

Hi. Would anybody explain a situation with iter6 and iter7 below? Strange thing - first one consumes no intput, while second consumes it all, while all the difference is peek which should do no processing (just copy next item in stream and return to user). What I am trying to do - is to write an i

Re: [Haskell-cafe] *GROUP HUG*

On Wed, Jun 1, 2011 at 3:28 AM, Daniel Fischer < daniel.is.fisc...@googlemail.com> wrote: > On Wednesday 01 June 2011 12:25:06, Adrien Haxaire wrote: > > On Wed, 01 Jun 2011 11:46:36 +0200, Henning Thielemann wrote: > > > Really, you can write foldr in terms of foldl? So far I was glad I > > > co

Re: [Haskell-cafe] Haskell School of Expression (graphics)

On Mon, May 30, 2011 at 1:19 AM, Jerzy Karczmarczuk wrote: > Henk-Jan van Tuyl commenting Andrew Coppin >> >> ... (about HOpenGL and H.Platform) ... >>> >>> Uh... yes, you might be right about that. However, AFAIK you still need >>> something with which to create a rendering surface in the first p

Re: [Haskell-cafe] How on Earth Do You Reason about Space?

Just out of interest, did you try reading the input as plain old Strings?  They may be unfashionable these days, and have their own type of badness in space and time performance, but might perhaps be a win over ByteStrings for extremely large datasets.Regards, MalcolmOn 01 Jun, 2011,at 02:49 PM

Re: [Haskell-cafe] Oracle Sessions in Takusen

On Wed, Jun 1, 2011 at 9:01 AM, Jason Dagit wrote: > > I'm CC'ing the takusen email list so that Oleg and Alistair will see > your message.  They are more familiar with the Oracle support than I > am. I should really link to the original message: http://www.haskell.org/pipermail/haskell-cafe/2011

Re: [Haskell-cafe] Oracle Sessions in Takusen

On Wed, Jun 1, 2011 at 7:44 AM, Dmitry Olshansky wrote: > Hello, > > Could anyone explain strange behavior of Takusen with OracleDB (OraClient > 11.x)? Several sequential sessions give "Seqmentation Fault" error. In case > of nested sessions it works well. I'm CC'ing the takusen email list so tha

Re: [Haskell-cafe] How on Earth Do You Reason about Space?

Hi Aleks, On Wed, Jun 1, 2011 at 12:14 AM, Aleksandar Dimitrov wrote: > I implemented your method, with these minimal changes (i.e. just using a main > driver in the same file.) > >> countUnigrams :: Handle -> IO (M.Map S.ByteString Int) >> countUnigrams = foldLines (\ m s -> M.insertWith (+) s 1

Re: [Haskell-cafe] Computing the memory footprint of a HashMap ByteString Int (Was: How on Earth Do You Reason about Space?)

On Wed, Jun 1, 2011 at 4:24 PM, Aleksandar Dimitrov wrote: > One additional thought: it might be interesting to provide this outside of > this > mailing list, perhaps as a documentation addendum to unordered-containers, > since > it really explains the size needs for HashMaps of ByteStrings to f

[Haskell-cafe] Oracle Sessions in Takusen

Hello, Could anyone explain strange behavior of Takusen with OracleDB (OraClient 11.x)? Several sequential sessions give "Seqmentation Fault" error. In case of nested sessions it works well. {-# LANGUAGE ScopedTypeVariables #-} module Main where import Database.Oracle.Enumerator import Control.Mo

Re: [Haskell-cafe] Computing the memory footprint of a HashMap ByteString Int (Was: How on Earth Do You Reason about Space?)

Hello Johan, On Wed, Jun 01, 2011 at 08:52:04AM +0200, Johan Tibell wrote: > I thought it'd be educational to do some back-of-the-envelope > calculations to see how much memory we'd expect to use to store words > in a HashMap ByteString Int. Thank you for your writeup, which is very informative!

Re: [Haskell-cafe] How on Earth Do You Reason about Space?

Aleksandar Dimitrov writes: > Now, here's some observations: on a 75M input file (minuscule, compared to > what > I actually need) this program will eat 30M of heap space (says profiling) and > return in 14 secs. > > I have two problems with that: a) that's too much heap space, b) the actual >

Re: [Haskell-cafe] How on Earth Do You Reason about Space?

Hi John, > I think the issue is data sharing, as Brandon mentioned. A bytestring > consists of an offset, length, and a pointer. You're using a chunk size of > 64k, which means the generated bytestrings all have a pointer to that 64k of > data. Suppose there's one new word in that 64k, and it's

Re: [Haskell-cafe] maybe a GHC bug but not sure

And after a lot more sleep and some digging, it turns out that the build script was forcing GCC to build the .o file as a 32 bit binary, and thus causing the "magic" mismatch. On Mon, May 30, 2011 at 11:20 PM, Edward Amsden wrote: > When building the Haskell Objective C bindings tool from >

Re: [Haskell-cafe] How on Earth Do You Reason about Space?

That sounds like a plausible reason why naive copying explodes space. Something like string interning would be good here... and since you're hashing already... Edward Excerpts from Daniel Fischer's message of Wed Jun 01 06:46:24 -0400 2011: > On Wednesday 01 June 2011 12:28:28, John Lato wrote: >

Re: [Haskell-cafe] How on Earth Do You Reason about Space?

On Wednesday 01 June 2011 12:28:28, John Lato wrote: > There are a few solutions to this. The first is to make a copy of the > bytestring so only the required data is retained. In my experiments > this wasn't helpful, but it would depend on your corpus. The second is > to start with smaller chun

Re: [Haskell-cafe] How on Earth Do You Reason about Space?

On Wednesday 01 June 2011 12:13:54, John Lato wrote: > > From: Brandon Moore > > > > > > I was worried data sharing might mean your keys > > retain entire 64K chunks of the input. However, it > > seems enumLines depends on the StringLike ByteString > > instance, which just converts to and from S

Re: [Haskell-cafe] *GROUP HUG*

On Wednesday 01 June 2011 12:25:06, Adrien Haxaire wrote: > On Wed, 01 Jun 2011 11:46:36 +0200, Henning Thielemann wrote: > > Really, you can write foldr in terms of foldl? So far I was glad I > > could > > manage the opposite direction. > > i didn't try it, that was just an example of how stran

Re: [Haskell-cafe] How on Earth Do You Reason about Space?

On Wed, Jun 1, 2011 at 12:55 AM, Aleksandar Dimitrov < aleks.dimit...@googlemail.com> wrote: > On Tue, May 31, 2011 at 11:30:06PM +0100, John Lato wrote: > > > None of these leak space for me (all compiled with ghc-7.0.3 -O2). > > Performance was pretty comparable for every version, although > Ale

Re: [Haskell-cafe] *GROUP HUG*

On Wed, 01 Jun 2011 11:46:36 +0200, Henning Thielemann wrote: Really, you can write foldr in terms of foldl? So far I was glad I could manage the opposite direction. i didn't try it, that was just an example of how strange/interesting the enthusiasm appeared to me when i started Haskell. go

Re: [Haskell-cafe] How on Earth Do You Reason about Space?

> > From: Brandon Moore > > > I was worried data sharing might mean your keys > retain entire 64K chunks of the input. However, it > seems enumLines depends on the StringLike ByteString > instance, which just converts to and from String. > That can't be efficient, but I suppose it avoids excessive

Re: [Haskell-cafe] *GROUP HUG*

Adrien Haxaire schrieb: > I fully agree. These are two of the three reasons which made me choose > haskell as the functional language to learn. Coding fortran all day, I > wanted a new approach on programming. The strong scientific roots of > haskell would give me stuff to learn and discover for a

[Haskell-cafe] ANN: dtd-types 0.2.0.0

The dtd-types package provides types for processing XML DTDs in Haskell. These types are intended to be compatible with and extend the set of types provided by John Millikin's xml-types package. The consensus seems to be to leave this as a separate package and not to merge it with xml-types. This

Re: [Haskell-cafe] ANNOUNCE: CamHac: Haskell Hackathon in Cambridge, UK, 12-14 August 2011

On 26/05/2011 15:35, Simon Marlow wrote: CamHac is happening - come and spend a long weekend in Cambridge hacking Haskell code in great surroundings with fantastic company! Full details on the wiki page: http://www.haskell.org/haskellwiki/CamHac When: Friday-Sunday 12-14 August 2011 Where: the

Re: [Haskell-cafe] Enabling GADTs breaks Rank2Types code compilation - Why?

On Tue, May 31, 2011 at 11:13 PM, wrote: > It definitely felt like I was running up against something like the > monomorphism restriction, but my bindings were function and not > pattern bindings, so I couldn't understand what was going on.  I had > even gone and re-read the GHC documentation > (h