Re: [Haskell-cafe] Haskell (GHC 7) on ARM
Joshua Poehls jos...@poehls.me writes: Hello Ben, Hello, Sorry for the latency. I'm currently on vacation in Germany so I haven't had terribly consistent Internet access. I've Cc'd haskell-cafe@ as I've been meaning to document my experiences anyways and your email seems like a good excuse to do this. I just got a Raspberry Pi and I'm interested in running Haskell on it. So far I'm running Arch Linux ARM and I noticed there is is a GHC package available, but it is version 6.12.3. Doing research online I saw that you did some work on adding GHCi support for ARM in GHC 7.4. I was wondering if you had anything to share related to running GHC/GHCI 7.4 on ARM, specifically Arch Linux ARM. Indeed my ARM linker patch was merged into GHC 7.4.2. This means that ARM is now a fully supported target platform for GHC, complete with GHCi support (which is pretty much necessary for many ubuiquitous packages). My ARM development environment consists of a PandaBoard (and before this a BeagleBoard) running Linaro's Ubuntu distribution. For this reason, I'm afraid I won't be of terribly much help in the case of Arch. That being said, GHC has a wonderful build system which has never given me trouble (except in cases of my own stupidity). Just installing the required development packages and following the build instructions on Wiki[1] is generally quite sufficient. I've also have some notes of my own[2] where I've collected my own experiences. As you likely know, GHC doesn't have a native ARM code generator of its own, instead relying on LLVM for low-level code generation. For this reason, you'll first need to have a working LLVM build. I have found that the ARM backend in the 3.0 release is a bit buggy and therefore generally pull directly from git (HEAD on my development box is currently sitting at 7750ff1e3cbb which seems to be stable). That being said, I haven't done much work in this space recently and it's quite likely that the 3.1 release is better in this respect. Compiling LLVM is one case where I have found the limited memory of my BeagleBoard (which is I believe is similar to the Raspberry Pi) to be quite troublesome. There are cases during linking where over a gigabyte of memory is necessary. At this stage the machine can sit for hours thrashing against its poor SD card making little progress. For this reason, I would strongly recommend that you cross-compile LLVM. The process is pretty straightforward and I have collected some notes on the matter[3]. The size of GHC means that in principle one would prefer to cross-compile. Unfortunately, support[4] for this is very new (and perhaps not even working/complete[5]?) so we have to make due with what we have. The build process itself is quite simple. You will want to be very careful to ensure that the ghc/libraries/ trees are sitting on the same branch as your ghc/ tree (with the ghc/sync-all script). Inconsistency here can lead to very ambiguous build failures. Otherwise, the build is nearly foolproof (insofar as this word can describe any build process). The build takes the better part of a day on my dual-core Pandaboard. I can't recall what the maximum memory consumption was but I think it might fit in 512MB. Lastly, if I recall correctly, you will find that you'll need to first build GHC 7.0 bootstrapped from 6.12 before you can build 7.4 (which requires a fairly new stage 0 GHC). Let the list know if you encounter any issues. I'll try to dust off my own development environment once I get back to the states next week to ensure that everything still works. I've been meaning to setup the PandaBoard as a build slave as Karel's has been failing for some time now (perhaps you could look into this, Karel?). Moreover, perhaps I can find a way to produce redistributable binaries to help others get started. Cheers, - Ben [1] http://hackage.haskell.org/trac/ghc/wiki/Building [2] http://bgamari.github.com/posts/ghc-llvm-arm.html [3] http://bgamari.github.com/posts/cross-compiling_llvm.html [4] http://hackage.haskell.org/trac/ghc/wiki/CrossCompilation [5] http://www.haskell.org/pipermail/cvs-ghc/2012-February/070791.html ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] How to select n random words from a file ...
Hi, I'm clearly new to haskell, and I suppose those is a basic question, but after a bit of searching I've been unable to figure out the best way to do this. I was first trying to find out how to, say, get a random element from a list, but I'm starting to think that may not be the best way (because list access isn't constant time, among other reasons). So, I wonder if there is a more direct way to just get a random word from a wordfile (i.e. one word per line) ... can anyone suggest a method? Ideally I'd like to be able to adapt this to get n random words from several files (i.e. randomly select n words from all files; i.e. just read them into one merged array and choose from there?) Thanks for any advice ... -- Noon Silk Fancy a quantum lunch? https://sites.google.com/site/quantumlunch/ Every morning when I wake up, I experience an exquisite joy — the joy of being this signature. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] converting functional dependencies to type families
On Thu, 7 Jun 2012, Simon Peyton-Jones wrote: Very useful! Maybe worth turning into a page on the Haskell wiki? I created one: http://www.haskell.org/haskellwiki/Functional_dependencies_vs._type_families ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to select n random words from a file ...
Hi, Look up reservoir sampling, it will most probably help. On Sun, Jun 10, 2012 at 6:21 AM, Noon Silk noonsli...@gmail.com wrote: Hi, I'm clearly new to haskell, and I suppose those is a basic question, but after a bit of searching I've been unable to figure out the best way to do this. I was first trying to find out how to, say, get a random element from a list, but I'm starting to think that may not be the best way (because list access isn't constant time, among other reasons). So, I wonder if there is a more direct way to just get a random word from a wordfile (i.e. one word per line) ... can anyone suggest a method? Ideally I'd like to be able to adapt this to get n random words from several files (i.e. randomly select n words from all files; i.e. just read them into one merged array and choose from there?) Thanks for any advice ... -- Noon Silk Fancy a quantum lunch? https://sites.google.com/site/quantumlunch/ Every morning when I wake up, I experience an exquisite joy — the joy of being this signature. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Eugene Kirpichov Principal Engineer, Mirantis Inc. http://www.mirantis.com/ Editor, http://fprog.ru/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Two parallel libraries from Japan
Hello everyone, I, Takayuki, author of Paraiso, would like to make some follow ups. First, the published version of the first paper on Paraiso is now available from http://iopscience.iop.org/1749-4699/5/1/015003 . Please go ahead and read it because the typeset is better, the journal is an open-access one and it has a most-read ranking! Second, I have started to refactor Paraiso. Please refer to the blog http://nushisblogger.blogspot.jp/search/label/ICFDP for the latest specifications and examples. Comments are welcome! -- MURANUSHI Takayuki The Hakubi Center for Advanced Research, Kyoto University http://www.hakubi.kyoto-u.ac.jp/02_mem/h22/muranushi.html 2012/6/7 Kazu Yamamoto k...@iij.ad.jp Hello cafe, I would like to announce two parallel libraries from Japan. - Paraiso (http://hackage.haskell.org/package/Paraiso) The purpose of this library is to design a high-level language for implementing explicit partial-differential equations solvers on supercomputers as well as today's advanced personal computers. Muranushi-san is also known as the author of Monadius and one of the two translators of Learn you. - GTALib (http://hackage.haskell.org/package/GTALib) This package provides the core functionalities of the GTA (Generate, Test, and Aggregate) programming framework on Haskell See Test, and Aggregate - A Calculation-based Framework for Systematic Parallel Programming with MapReduce for more information. Regards, --Kazu ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] ANN: scrobble-0.1.0.1: Scrobbling server
Heyo, If you use Last.fm/Libre.fm you might be interested in running your own local scrobbling server in Haskell. $ cabal update $ cabal install scrobble $ scrobble-server 8910 Source is here with further instructions for audio players and such: https://github.com/chrisdone/scrobble Exactly what the server does with the scrobbles it receives is purely up to you, use it as a library and do as you please. Personally I might work on a Last.fm replacement, at least as far as the statistics/reporting generation goes. Ciao! ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Two parallel libraries from Japan
Thanks these look very interesting! It seems that the parallelism is only available vai the JoinList module, am i correct in thinking this (or at least that is the only place where it is clearly inidicated in the haddock and source code). Are there any plans to leverage Cloud Haskell once the mature variant is released? -Carter On Thu, Jun 7, 2012 at 4:21 AM, Kazu Yamamoto k...@iij.ad.jp wrote: Hello cafe, I would like to announce two parallel libraries from Japan. - Paraiso (http://hackage.haskell.org/package/Paraiso) The purpose of this library is to design a high-level language for implementing explicit partial-differential equations solvers on supercomputers as well as today's advanced personal computers. Muranushi-san is also known as the author of Monadius and one of the two translators of Learn you. - GTALib (http://hackage.haskell.org/package/GTALib) This package provides the core functionalities of the GTA (Generate, Test, and Aggregate) programming framework on Haskell See Test, and Aggregate - A Calculation-based Framework for Systematic Parallel Programming with MapReduce for more information. Regards, --Kazu ___ 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] Haskell User Group Hamburg (Germany) - Meeting Thursday June 14th 2012
Hello cafe, there's an upcomming meeting of the Haskell user group Hamburg next Thursday (June 14th). We'll start 19:00 at the Xing AG in Hamburg (Gänsemarkt 43, 20354 Hamburg). Falko Peters will give a short talk about hedis ( http://hackage.haskell.org/package/hedis), a Redis client written in Haskell. Although this announcement is written in english the talk will be given in german. So if you are interested to come, have a look at our doodle (also in german) and give us a short note if you want to join us. http://www.doodle.com/3fz45uqupp8pzutb Further announcements will be made via Twitter, so you may want to follow https://twitter.com/hug_hh. Stefan Schmidt ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to select n random words from a file ...
On Sun, Jun 10, 2012 at 6:21 AM, Noon Silk noonsli...@gmail.com wrote: Hi, I'm clearly new to haskell, and I suppose those is a basic question, but after a bit of searching I've been unable to figure out the best way to do this. I was first trying to find out how to, say, get a random element from a list, but I'm starting to think that may not be the best way (because list access isn't constant time, among other reasons). So, I wonder if there is a more direct way to just get a random word from a wordfile (i.e. one word per line) ... can anyone suggest a method? My preferred option, assuming the file sizes make it amenable, is to use Iteratees to fold the wordlists into an IntMap of words. You can then take the size of the map and choose n unique Ints in the range. Note that any algorithm is going to include these basic steps. (Get the size, pick randoms, access the words at the key/line number). The most direct approach would basically be imperative and in the IO monad, using things like openFile and hSeek. This approach gets harder if you want to pull words out of multiple wordlists. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] attoparsec double precision, quickCheck and aeson
On Wed, Jun 6, 2012 at 6:20 AM, Doug McIlroy d...@cs.dartmouth.eduwrote: Last I looked (admittedly quite a while ago), the state of the art was strtod in http://www.netlib.org/fp/dtoa.c. (Alas, dtoa.c achieves calculational perfection via a murmuration of #ifdefs.) That was indeed the state of the art for about three decades, until Florian Loitsch showed up in 2010 with an algorithm that is usually far faster: http://www.serpentine.com/blog/2011/06/29/here-be-dragons-advances-in-problems-you-didnt-even-know-you-had/ Unfortunately, although I've written Haskell bindings to his library, said library is written in C++, and our FFI support for C++ libraries is negligible and buggy. As a result, that code is disabled by default. It's disheartening to hear that important Haskell code has needlessly fallen from perfection--perhaps even deliberately. Indeed (and yes, it's deliberate). If I had the time to spare, I'd attempt to fix the situation by porting Loitsch's algorithm to Haskell or C, but either one would be a lot of work - the library is 5,600 lines of tricky code. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to select n random words from a file ...
An interesting related problem is if you are only allowed one pass through the data how would you randomly choose one word. -- -- Regards, KC ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
