[Haskell-cafe] Weird problem: Couldn't read cabal file hashable/1.2.0.0/hashable.cabal
Hi, A friend of mine is trying to install my timeplotters (see email signature). He's getting a weird error: one of the tools installs fine but the other one fails with the error Couldn't read cabal file hashable/ 1.2.0.0/hashable.cabal; curiously, so does running cabal install cabal-install. Even more curiously, hashable 1.2.0.0 does not appear anywhere in the list of dependencies, even indirect. Look: $ cabal -v3 install cabal-install searching for ghc in path. found ghc at /usr/bin/ghc (/usr/bin/ghc,[--numeric-version]) /usr/bin/ghc is version 7.0.3 looking for tool ghc-pkg near compiler in /usr/bin found ghc-pkg in /usr/bin/ghc-pkg (/usr/bin/ghc-pkg,[--version]) /usr/bin/ghc-pkg is version 7.0.3 (/usr/bin/ghc,[--supported-languages]) (/usr/bin/ghc,[--info]) Reading installed packages... (/usr/bin/ghc-pkg,[dump,--global,-v2]) (/usr/bin/ghc-pkg,[dump,--user,-v2]) (/usr/bin/ghc,[--print-libdir]) Reading available packages... Resolving dependencies... cabal: Couldn't read cabal file hashable/1.2.0.0/hashable.cabal He's using haskell platform on Ubuntu 12.04. $ ghc —version The Glorious Glasgow Haskell Compilation System, version 7.0.3 $ cabal —version cabal-install version 0.10.2 using version 1.10.1.0 of the Cabal library He *did* try erasing ~/.cabal, ~/.ghc and /usr/lib/ghc and then reinstalling haskell-platform package - it didn't change anything. He doesn't remember ever having Haskell installed before, but that can't be completely ruled out. I just tried installing a fresh Ubuntu 12.04 onto a VM and I did not have this problem that he has. What additional information can I ask him for? Maybe somebody already encountered this problem? (Actually, I have a whole strace cabal install cabal-install, but it's 33Mb - I can upload it somewhere if it could be helpful). -- Eugene Kirpichov http://www.linkedin.com/in/eugenekirpichov http://jkff.info/software/timeplotters - my performance visualization tools ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Weird problem: Couldn't read cabal file hashable/1.2.0.0/hashable.cabal
The curious thing about that strace is that it doesn't ever attempt to open hashable.cabal - in fact, it isn't attempting to open *any* .cabal file whatsoever before failing! So I'm totally confused as to why cabal might be complaining that it can't open hashable.cabal. On Sun, Jan 6, 2013 at 10:05 PM, Eugene Kirpichov ekirpic...@gmail.comwrote: Couldn't read cabal file -- Eugene Kirpichov http://www.linkedin.com/in/eugenekirpichov http://jkff.info/software/timeplotters - my performance visualization tools ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Decent docs to my visualization tools
Hi cafe, I just finally published a decent documentation website and binary distributions for my log visualization tools written in Haskell - http://jkff.info/software/timeplotters/ . I think now they might actually stand a chance of starting to be adopted by a wider circle than my friends :) Feedback and sharing would be very welcome. -- Eugene Kirpichov http://www.linkedin.com/in/eugenekirpichov ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Incremental regular expressions - article and library
Hi Haskellers, I just published an article that can be interesting to lovers of functional programming, even though it's not directly relevant to Haskell per se. http://jkff.info/articles/ire/ It's based on Dan Piponi's blogpost Fast incremental regular expression matching with monoids http://blog.sigfpe.com/2009/01/fast-incremental-regular-expression.html but expands Dan's ideas to include *locating* matches, matching multiple regular expressions at once, using a more compact datastructure than fingertrees, etc. And - sorry - the implementation is in Java, for reasons explained in the article :) -- Eugene Kirpichov http://www.linkedin.com/in/eugenekirpichov ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] tplot (out of memory)
Hi, Wow, that's weird. I wonder what kinds of fonts were missing? I was just using the default cairo font everywhere. On Fri, Nov 30, 2012 at 11:27 PM, Malcolm Wallace malcolm.wall...@me.comwrote: For the record, it turned out that the key difference between the linux machines was the fonts packages installed via RPM. The strace utility told me that the crash happened shortly after cairo/pango attempted (and failed) to open some font configuration files. After installing some of the X11 font packages (and some others too), the crash went away. On 18 Oct 2012, at 09:55, malcolm.wallace wrote: Did you ever solve this? I have a similar message ( user error (out of memory) ) arising from a different app (not tplot) that uses the Haskell Chart library (and cairo underneath). On some linux machines, it crashes, on others it works fine. I can find no environment differences between the machines. The app does not use a lot of memory, and the machine is not running out of physical or swap. Regards, Malcolm On 04 Sep, 2012,at 04:01 PM, Eugene Kirpichov ekirpic...@gmail.com wrote: Hi Manish, Please provide the input file, I'll debug this. On Mon, Sep 3, 2012 at 1:06 PM, Manish Trivedi trivman...@gmail.com wrote: Hi, I am running into a weird out of memory issue. While running timeplot over an input file having ~800 rows. From below provided info, seems like machine has enough ram (1849MB). Please let me know if anyone has pointers. # free -m total used free shared buffers cached Mem: 3825 1975 1849 0 13 71 -/+ buffers/cache: 1891 1934 Swap: 4031 111 3920 #time tplot -o out.png -or 1024x768 -k 'CurrentPerHour' 'lines' -k 'RequiredPerHour' 'lines' -if adgroup_delivery_chart.input -tf 'date %Y-%m-%d %H:%M:%OS' tplot: user error (out of memory) real 0m0.026s user 0m0.018s sys 0m0.008s -Manish ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Eugene Kirpichov http://www.linkedin.com/in/eugenekirpichov ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Eugene Kirpichov http://www.linkedin.com/in/eugenekirpichov ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Maximum bipartite matching: 24 lines
Hi, fwd = foldr (\(x,y) - M.insertWith (++) x [y]) M.empty $ S.toList g Use foldl' here, foldr is absolutely useless here and it only consumes the stack space as your operation is strict. As for the actual code: I'd prefer the code itself to be more readable, rather than have a lot of literate comments around it; currently, IMO all the uncurry's, flips, eithers, maybes and point-free style hurt readability heavily. I think it would be better to devise your own very simple datatypes for this. Maybe I'm too capricious or heretically unhaskellish, I'll probably try to write my own version as an exercise :) On Mon, Oct 22, 2012 at 1:28 PM, Stefan Klinger all-li...@stefan-klinger.de wrote: Hello. I have written a function that calculates maximum cardinality matchings on bipartite graphs. It's only 24 lines of code. It seems (tested, not proven) to run faster, use less memory, and scale better than using MaxFlow from FGL with constant weight and additional source and sink nodes. But it's not as good as Hopcroft–Karp would be. Attached is the module MaxMatching which also contains extensive documentation of the rationale behind its design. I would hope to get any feedback on this: What do you think about the approach? Did I oversee anything? Do you know of any other purely functional solution to this problem? Just as an exmaple, run `ghci MaxMatching.lhs` and then use matching $ S.fromList [(1,'a'),(1,'b'),(2,'a'),(2,'c'),(3,'b')] to calculate a maximum cardinality matching of the graph shown below. 1---a Note the somewhat awkward type of the matching \ /function, returning a Map instead of a Set, with the X edges being backwards! / \ 2 b matching :: (Ord b, Ord a) = S.Set (a, b) - M.Map b a \ / X On my machine, it takes less than 2s on 10k edges / \or 225 nodes. 3 c Comments are welcome! Thank you! Stefan -- Stefan Klinger o/klettern /\/ bis zum send plaintext only - max size 32kB - no spam \ Abfallen http://stefan-klinger.de ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Eugene Kirpichov http://www.linkedin.com/in/eugenekirpichov We're hiring! http://tinyurl.com/mirantis-openstack-engineer ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] tplot (out of memory)
Hi, I didn't - because I didn't run into this myself. Manish, maybe you did? :) On Thu, Oct 18, 2012 at 1:55 AM, malcolm.wallace malcolm.wall...@me.com wrote: Did you ever solve this? I have a similar message ( user error (out of memory) ) arising from a different app (not tplot) that uses the Haskell Chart library (and cairo underneath). On some linux machines, it crashes, on others it works fine. I can find no environment differences between the machines. The app does not use a lot of memory, and the machine is not running out of physical or swap. Regards, Malcolm On 04 Sep, 2012,at 04:01 PM, Eugene Kirpichov ekirpic...@gmail.com wrote: Hi Manish, Please provide the input file, I'll debug this. On Mon, Sep 3, 2012 at 1:06 PM, Manish Trivedi trivman...@gmail.com wrote: Hi, I am running into a weird out of memory issue. While running timeplot over an input file having ~800 rows. From below provided info, seems like machine has enough ram (1849MB). Please let me know if anyone has pointers. # free -m total used free shared buffers cached Mem: 3825 1975 1849 0 13 71 -/+ buffers/cache: 1891 1934 Swap: 4031 111 3920 #time tplot -o out.png -or 1024x768 -k 'CurrentPerHour' 'lines' -k 'RequiredPerHour' 'lines' -if adgroup_delivery_chart.input -tf 'date %Y-%m-%d %H:%M:%OS' tplot: user error (out of memory) real 0m0.026s user 0m0.018s sys 0m0.008s -Manish ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Eugene Kirpichov http://www.linkedin.com/in/eugenekirpichov ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Eugene Kirpichov http://www.linkedin.com/in/eugenekirpichov We're hiring! http://tinyurl.com/mirantis-openstack-engineer ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] 64-bit vs 32-bit haskell platform on Mac: misleading notice on Platform website?
Hi Mark, Thank you for the clarification. I think, then, that we should indeed provide a link to a notice about native libraries - like, if you're using native libraries, make sure their architecture is 32-bit or universal as well; in case of MacPorts you can achieve this by doing port install libfoo +universal; in case of brew by brew install libfoo --universal. On Mon, Oct 8, 2012 at 9:52 PM, Mark Lentczner mark.lentcz...@gmail.com wrote: I'm the source of the 32-bit recommendation, and the HP Mac distribution builder To summarize what I read in this thread: 32-bit GHC/HP didn't work with 64-bit Cario libs Some libs available via brew were 64-bit, and 32-bit ones would have to be compiled There is still some bug with 64-bit ghci and some graphics libs There is a ghc bug with 64-bit on mac (bug #7040), which isn't fixed until 7.6 There seemed to be the implication that a 64-bit ghc would work with 32-bit libs, but I don't think that's true. Mac doesn't (generally) support mixed modes in the same executable. All system libs are shipped dual-architecture. I don't think there are any pre-installed libs that are shipped 64-bit only. The problem seen with Cairo would cut both ways: If one had installed the 32-bit version of Cairo, one would see the same problem with the 64-bit HP: wrong architecture. Since code compiled with the 32-bit system is both faster, and uses less memory, and it has been the case that all libs are either shipped dual-arch, or easily available as 32-bit, and there were known problems with the 64-bit version for some use cases, it seemed to me to be best to suggest the 32-bit version by default. The major source of the problems in the OP, seem to be that MacPorts and/or brew don't appear to follow the Mac OS X lib standard of installing libs dual arch. A brief look at the MacPorts page indicated that there were various rules (OS version and processor version) that determined which arch. it built by default. Perhaps we should tell people to install the HP architecture that matches the architecture that they use for MacPorts or brew. However, I bet most people don't know, so we'd need a pointer to where they could find out the defaults for those systems, or how to establish what their system is using. Finally, I note that HP 2012.4.0.0 (out in a month) will ship with GHC 7.4.2, and so will still have the above bugs. - Mark ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Eugene Kirpichov http://www.linkedin.com/in/eugenekirpichov We're hiring! http://tinyurl.com/mirantis-openstack-engineer ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] 64-bit vs 32-bit haskell platform on Mac: misleading notice on Platform website?
Johan, should I also file the bugreport remove the suggestion to install 32-bit platform there, or is there a different place for bugs of the platform website? On Mon, Oct 8, 2012 at 7:25 AM, Johan Tibell johan.tib...@gmail.com wrote: On Mon, Oct 8, 2012 at 3:28 AM, Christiaan Baaij christiaan.ba...@gmail.com wrote: Hi, I finally found another OS X mountain lion install and can confirm the behaviour I described earlier: 32-bit: compiled code works, interpreted code works 64-bit: compiled code works, interpreted code fails Here's the test case: - cabal install gloss --flags-GLUT GLFW - cabal unpack gloss-examples - cd gloss-examples-1.7.6.2/picture/GameEvent - ghci -fno-ghci-sandbox Main.hs - main I get the following crash report: http://pastebin.com/jZjfFtm7 The weird thing is the following: When I run 'ghci' from inside 'gdb' (to find the origin for the segfault), everything works fine: ghci: segfault ghci from gdb: everything works I have no idea what's going on, so if anyone has any pointers on how to make sure ghci behaves the same in gdb please let me know. Could you please file a bug report at: http://hackage.haskell.org/trac/ghc/ Thanks! ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Eugene Kirpichov http://www.linkedin.com/in/eugenekirpichov We're hiring! http://tinyurl.com/mirantis-openstack-engineer ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] 64-bit vs 32-bit haskell platform on Mac: misleading notice on Platform website?
Hi, I installed Haskell Platform 32-bit on a fresh 64-bit mac, because the page http://www.haskell.org/platform/mac.html says: Pick the 32-bit vesion, unless you have a specific reason to use the 64-bit version. The 32-bit one is slightly faster for most programs. Then, during the installation of a package, the following happeed: Loading package cairo-0.12.3.1 ... command line: can't load .so/.DLL for: /opt/local/lib/libz.dylib (dlopen(/opt/local/lib/libz.dylib, 9): no suitable image found. Did find: /opt/local/lib/libz.dylib: mach-o, but wrong architecture) That libz.dylib is a 64-bit library and it can't be used by 32-bit Haskell platform. QUESTION: It seems to me that most people, at least most who care about slightly faster programs, are likely to run into something like this - using native 64-bit libraries. Compatibility exists only in the opposite direction. Wouldn't it be appropriate to remove this notice and ask people to use the 64-bit version unless they have a specific reason not to? -- Eugene Kirpichov http://www.linkedin.com/in/eugenekirpichov We're hiring! http://tinyurl.com/mirantis-openstack-engineer ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Choosing color of the track
Hi Manish, The meaning of @ is not what you think it is. It merely draws colored bars, it does NOT control the color of other kinds of charts. Here's how what you want can be achieved: * Remove the @ lines * Append a common prefix to the input tracks you want to be displayed on the same output track, e.g. t.: 2012-09-18 00:10:48,166 =t.CurrentPerHour13057 0.0 2012-09-18 00:10:58,155 =t.CurrentPerHour13057 0.0 .. 2012-09-18 03:58:28,159 =t.PacingReqPerHr13057 2375.0534412521242 2012-09-18 03:58:38,161 =t.PacingReqPerHr13057 2375.383005739316 * Use the within diagram kind: tplot -dk ''within[.] lines Then you'll have a single output track where data from these input tracks is displayed with different color. However, you don't control the precise color (I just never really needed to control it, I only needed it to be different for different tracks). On Mon, Sep 17, 2012 at 9:40 PM, Manish Trivedi trivman...@gmail.com wrote: Hi Folks, I am trying to plot two tracks with different colors. Following is my input file, -- 2012-09-18 00:10:48,166 @CurrentPerHour13057 Red 2012-09-18 00:10:48,166 =CurrentPerHour13057 0.0 2012-09-18 00:10:58,155 =CurrentPerHour13057 0.0 2012-09-18 00:11:08,203 =CurrentPerHour13057 0.0 2012-09-18 00:11:18,166 =CurrentPerHour13057 0.0 2012-09-18 00:11:28,159 =CurrentPerHour13057 0.0 2012-09-18 00:11:38,170 =CurrentPerHour13057 0.0 2012-09-18 00:11:48,175 =CurrentPerHour13057 0.0 2012-09-18 00:11:58,174 =CurrentPerHour13057 0.0 2012-09-18 00:12:08,216 =CurrentPerHour13057 0.0 2012-09-18 00:12:18,218 =CurrentPerHour13057 0.0 2012-09-18 03:58:28,159 @PacingReqPerHr13057 Blue 2012-09-18 03:58:28,159 =PacingReqPerHr13057 2375.0534412521242 2012-09-18 03:58:38,161 =PacingReqPerHr13057 2375.383005739316 2012-09-18 03:58:48,175 =PacingReqPerHr13057 2375.713057258422 2012-09-18 03:58:58,160 =PacingReqPerHr13057 2376.0422443063935 2012-09-18 03:59:08,192 =PacingReqPerHr13057 2376.3730727321126 2012-09-18 03:59:18,207 =PacingReqPerHr13057 2375.9038854561304 2012-09-18 03:59:28,168 =PacingReqPerHr13057 2376.232615497 2012-09-18 03:59:38,156 =PacingReqPerHr13057 2376.5619853019184 2012-09-18 03:59:48,160 =PacingReqPerHr13057 2376.892145685344 2012-09-18 03:59:58,160 =PacingReqPerHr13057 2377.65743067 - tplot -o /root/color.png -or 1024x768 -k 'CurrentPerHour' 'lines' -k 'PacingReqPerHr' 'lines' -if /root/color.input -tf 'date %Y-%m-%d %H:%M:%OS' I cant get to print plots in different color. Could anyone point out what am I doing wrong? Thanks, Manish ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Eugene Kirpichov http://www.linkedin.com/in/eugenekirpichov We're hiring! http://tinyurl.com/mirantis-openstack-engineer ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Choosing color of the track
Hi, Suppose you have data like this: 2012-09-18 00:10:48,166 =responseTime 53 ... Then you should just use -dk 'quantile 0.95' and you'll see a graph of stacked bars like [][Y] (but vertical) where XXX is min..95% and YYY is 95%..max. On Tue, Sep 18, 2012 at 11:44 AM, Manish Trivedi trivman...@gmail.com wrote: Thanks a ton Eugene. that worked like a charm :) Appreciate you looking into this and suggesting me the correct approach. I have another question that if I had single track storing response time of each request, how could I get 95th percentile of the response time. I know TimePlot wiki has quantile example but I havent been able to successfully use it. Regards, -Manish On Tue, Sep 18, 2012 at 10:48 AM, Eugene Kirpichov ekirpic...@gmail.com wrote: Hi Manish, The meaning of @ is not what you think it is. It merely draws colored bars, it does NOT control the color of other kinds of charts. Here's how what you want can be achieved: * Remove the @ lines * Append a common prefix to the input tracks you want to be displayed on the same output track, e.g. t.: 2012-09-18 00:10:48,166 =t.CurrentPerHour13057 0.0 2012-09-18 00:10:58,155 =t.CurrentPerHour13057 0.0 .. 2012-09-18 03:58:28,159 =t.PacingReqPerHr13057 2375.0534412521242 2012-09-18 03:58:38,161 =t.PacingReqPerHr13057 2375.383005739316 * Use the within diagram kind: tplot -dk ''within[.] lines Then you'll have a single output track where data from these input tracks is displayed with different color. However, you don't control the precise color (I just never really needed to control it, I only needed it to be different for different tracks). On Mon, Sep 17, 2012 at 9:40 PM, Manish Trivedi trivman...@gmail.com wrote: Hi Folks, I am trying to plot two tracks with different colors. Following is my input file, -- 2012-09-18 00:10:48,166 @CurrentPerHour13057 Red 2012-09-18 00:10:48,166 =CurrentPerHour13057 0.0 2012-09-18 00:10:58,155 =CurrentPerHour13057 0.0 2012-09-18 00:11:08,203 =CurrentPerHour13057 0.0 2012-09-18 00:11:18,166 =CurrentPerHour13057 0.0 2012-09-18 00:11:28,159 =CurrentPerHour13057 0.0 2012-09-18 00:11:38,170 =CurrentPerHour13057 0.0 2012-09-18 00:11:48,175 =CurrentPerHour13057 0.0 2012-09-18 00:11:58,174 =CurrentPerHour13057 0.0 2012-09-18 00:12:08,216 =CurrentPerHour13057 0.0 2012-09-18 00:12:18,218 =CurrentPerHour13057 0.0 2012-09-18 03:58:28,159 @PacingReqPerHr13057 Blue 2012-09-18 03:58:28,159 =PacingReqPerHr13057 2375.0534412521242 2012-09-18 03:58:38,161 =PacingReqPerHr13057 2375.383005739316 2012-09-18 03:58:48,175 =PacingReqPerHr13057 2375.713057258422 2012-09-18 03:58:58,160 =PacingReqPerHr13057 2376.0422443063935 2012-09-18 03:59:08,192 =PacingReqPerHr13057 2376.3730727321126 2012-09-18 03:59:18,207 =PacingReqPerHr13057 2375.9038854561304 2012-09-18 03:59:28,168 =PacingReqPerHr13057 2376.232615497 2012-09-18 03:59:38,156 =PacingReqPerHr13057 2376.5619853019184 2012-09-18 03:59:48,160 =PacingReqPerHr13057 2376.892145685344 2012-09-18 03:59:58,160 =PacingReqPerHr13057 2377.65743067 - tplot -o /root/color.png -or 1024x768 -k 'CurrentPerHour' 'lines' -k 'PacingReqPerHr' 'lines' -if /root/color.input -tf 'date %Y-%m-%d %H:%M:%OS' I cant get to print plots in different color. Could anyone point out what am I doing wrong? Thanks, Manish ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Eugene Kirpichov http://www.linkedin.com/in/eugenekirpichov We're hiring! http://tinyurl.com/mirantis-openstack-engineer -- Eugene Kirpichov http://www.linkedin.com/in/eugenekirpichov We're hiring! http://tinyurl.com/mirantis-openstack-engineer ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Choosing color of the track
Hi, I'm the author and I'll reply tomorrow, sorry, going to sleep now :) thanks for the interest in the tools anyway! 17.09.2012, в 21:40, Manish Trivedi trivman...@gmail.com написал(а): Hi Folks, I am trying to plot two tracks with different colors. Following is my input file, -- 2012-09-18 00:10:48,166 @CurrentPerHour13057 Red 2012-09-18 00:10:48,166 =CurrentPerHour13057 0.0 2012-09-18 00:10:58,155 =CurrentPerHour13057 0.0 2012-09-18 00:11:08,203 =CurrentPerHour13057 0.0 2012-09-18 00:11:18,166 =CurrentPerHour13057 0.0 2012-09-18 00:11:28,159 =CurrentPerHour13057 0.0 2012-09-18 00:11:38,170 =CurrentPerHour13057 0.0 2012-09-18 00:11:48,175 =CurrentPerHour13057 0.0 2012-09-18 00:11:58,174 =CurrentPerHour13057 0.0 2012-09-18 00:12:08,216 =CurrentPerHour13057 0.0 2012-09-18 00:12:18,218 =CurrentPerHour13057 0.0 2012-09-18 03:58:28,159 @PacingReqPerHr13057 Blue 2012-09-18 03:58:28,159 =PacingReqPerHr13057 2375.0534412521242 2012-09-18 03:58:38,161 =PacingReqPerHr13057 2375.383005739316 2012-09-18 03:58:48,175 =PacingReqPerHr13057 2375.713057258422 2012-09-18 03:58:58,160 =PacingReqPerHr13057 2376.0422443063935 2012-09-18 03:59:08,192 =PacingReqPerHr13057 2376.3730727321126 2012-09-18 03:59:18,207 =PacingReqPerHr13057 2375.9038854561304 2012-09-18 03:59:28,168 =PacingReqPerHr13057 2376.232615497 2012-09-18 03:59:38,156 =PacingReqPerHr13057 2376.5619853019184 2012-09-18 03:59:48,160 =PacingReqPerHr13057 2376.892145685344 2012-09-18 03:59:58,160 =PacingReqPerHr13057 2377.65743067 - tplot -o /root/color.png -or 1024x768 -k 'CurrentPerHour' 'lines' -k 'PacingReqPerHr' 'lines' -if /root/color.input -tf 'date %Y-%m-%d %H:%M:%OS' I cant get to print plots in different color. Could anyone point out what am I doing wrong? Thanks, Manish ___ 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
Re: [Haskell-cafe] Help a young graduate haskeller to land its dream job
Hi Alfredo, You might look at the various bigdata companies. I was surprised by how many of them are using Scala or Clojure - it's definitely over 50%. Looks like FP is really gaining traction in this area. On Wed, Sep 12, 2012 at 11:48 AM, Alfredo Di Napoli alfredo.dinap...@gmail.com wrote: Hi everyone, If this mail sound strange to you, you are free to ignore it. My name is Alfredo Di Napoli and I'm a 24-year-old programmer from Rome, Italy. I've graduated in May and I'm currently working as an intern for a company involved in the defence field. In my spare time, though, I study functional programming, especially Haskell. FP is my true passion and I'm another dreamer trying to land the job he loves. In a nutshell I'm looking for every possibility to do Haskell/functional programming in Europe/North Europe. I'm throwing this stone into this pond because life has endless possibilities, who knows? :) A disclaimer, though: I'm not an expert Haskeller, but I'm very passionate about technology and I love learning (I've obviously already read LYAH and RWH). You can find more information about me (including my CV if interested) here: www.alfredodinapoli.com Oh! One last thing! I would be very grateful to everyone willing to spent two minutes of his time giving me any kind of suggestion about the FP job world or how to prepare/improve myself for the foreseeable future. Thanks again, and sorry for the OT/spammish plug. Humbly, Alfredo Di Napoli ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Eugene Kirpichov http://www.linkedin.com/in/eugenekirpichov We're hiring! http://tinyurl.com/mirantis-openstack-engineer ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] tplot (out of memory)
Hi Manish, Please provide the input file, I'll debug this. On Mon, Sep 3, 2012 at 1:06 PM, Manish Trivedi trivman...@gmail.com wrote: Hi, I am running into a weird out of memory issue. While running timeplot over an input file having ~800 rows. From below provided info, seems like machine has enough ram (1849MB). Please let me know if anyone has pointers. # free -m total used free sharedbuffers cached Mem: 3825 1975 1849 0 13 71 -/+ buffers/cache: 1891 1934 Swap: 4031111 3920 #time tplot -o out.png -or 1024x768 -k 'CurrentPerHour' 'lines' -k 'RequiredPerHour' 'lines' -if adgroup_delivery_chart.input -tf 'date %Y-%m-%d %H:%M:%OS' tplot: user error (out of memory) real0m0.026s user0m0.018s sys0m0.008s -Manish ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Eugene Kirpichov http://www.linkedin.com/in/eugenekirpichov ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] wondering about a MonadIO instance for a heap data type
Use Debug.Trace. It does not make sense to declare that heap is a monad, as a monad is an abstraction of sequencing computations, and a heap is not an abstraction of sequencing computations at all. You don't make your String class implement the rendering engine interface just because you want to use it in a computer game program, equally you dont pretend that a heap is a way of sequencing computations just because you want to sequence computations related to heaps. The actual computation in your case is the heapsort function, not the heap. If you absolutely must use IO, add IO to the functions type. 11.07.2012, в 15:19, Qi Qi qiqi...@gmail.com написал(а): Hi, I was wondering about creating an instance of MonadIO for a heap data. Any hints? data Heap a = E | T Int a (Heap a) (Heap a) deriving (Eq, Ord, Read, Show) The reason is that I want to use liftIO during a heapsort to print out intermediate results. Thanks. Qi Qi ___ 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
Re: [Haskell-cafe] wondering about a MonadIO instance for a heap data type
List is a monad because it has an associated way of sequencing computations: namely, collect results of the second computation invoked on all results of the first computation. That's not because List is a data structure (similarly to Heap), it's because it is associated with the computational abstraction of computations with multiple results. The heap data structure does not have an associated computational abstraction, at least not that one I'm aware of, and definitely not one that would make any sense in the context of heapsort. So it doesn't make sense to pretend that it does. On Wed, Jul 11, 2012 at 5:00 PM, Qi Qi qiqi...@gmail.com wrote: List [] is a monad, why not for heap data. Heap data could be an instance of Monad too. I have the heapsort function, and just wanted to rewrite a verbose version of it by using liftIO. But I would look into Debug.Trace. Thanks for your hint. Qi On Wednesday, July 11, 2012 5:28:17 PM UTC-5, Eugene Kirpichov wrote: Use Debug.Trace. It does not make sense to declare that heap is a monad, as a monad is an abstraction of sequencing computations, and a heap is not an abstraction of sequencing computations at all. You don't make your String class implement the rendering engine interface just because you want to use it in a computer game program, equally you dont pretend that a heap is a way of sequencing computations just because you want to sequence computations related to heaps. The actual computation in your case is the heapsort function, not the heap. If you absolutely must use IO, add IO to the functions type. 11.07.2012, в 15:19, Qi Qi qiqi...@gmail.com написал(а): Hi, I was wondering about creating an instance of MonadIO for a heap data. Any hints? data Heap a = E | T Int a (Heap a) (Heap a) deriving (Eq, Ord, Read, Show) The reason is that I want to use liftIO during a heapsort to print out intermediate results. Thanks. Qi Qi ___ 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 mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Eugene Kirpichov http://www.linkedin.com/in/eugenekirpichov ___ 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] Finding the average in constant space
A lot of people have done this :) eg from me: google up a fairly recent thread from me about processing streams and perhaps the keyword timeplot (writing from a dying phone, can't do myself) 27.05.2012, в 12:04, Chris Wong chrisyco+haskell-c...@gmail.com написал(а): Hello all I just came up with a way of executing multiple folds in a single pass. In short, we can write code like this: average = foldLeft $ (/) $ sumF * lengthF and it will only traverse the input list once. The code is at: https://gist.github.com/2802644 My question is: has anyone done this already? If not, I might release this on Hackage -- it seems quite useful. Chris ___ 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
Re: [Haskell-cafe] Google Summer of Code - Lock-free data structures
Though of course you can implement CAS in terms of STM, CAS is much more low-level and will probably be many times (though not asymptotically) faster. On Thu, Mar 29, 2012 at 12:01 PM, Heinrich Apfelmus apfel...@quantentunnel.de wrote: Florian Hartwig wrote: Hi everyone, I would like to do the GSoC project outlined in http://hackage.haskell.org/trac/summer-of-code/ticket/1608 One of Haskell's great strengths is its support for all kinds of concurrent and parallel programmming, so I think that the Haskell ecosystem would benefit from having a wider range of efficient concurrent data structures. Also, more selfishly, I remember reading the article in CACM last summer and thinking that the whole idea of updating data structures directly using atomic compare-and-swap was really cool, so I would love to have an excuse to play around with it. Some (initial) ideas for lock-free data structures worth implementing: 1. A lock-free priority queue, e.g. using the approach based on skip-lists explained in [2] 2. Stacks, see [1] and [3] 3. Hash tables [4] but if anyone has other suggestions, I would obviously happy to hear them. Since I don't know much about concurrency, I have a simple question: what is the difference between atomic compare-and-swap and software transactional memory? Both are lock-free? Is it possible to implement every data structure based on CAS in terms of STM? What are the drawbacks? The other way round? Best regards, Heinrich Apfelmus -- http://apfelmus.nfshost.com ___ 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
[Haskell-cafe] Inject cabal version or VCS version as a CPP macro
Hi, I'd like my program to print something like this is $program 1.0.4 git 45fea6b when invoked with --version, or at least just the 1.0.4 part. Can Cabal expose the version as a preprocessor macro by default, or do I have to use Build-Type: Custom and add a preprocessing step of my own? -- 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] Inject cabal version or VCS version as a CPP macro
Thanks, this is exactly what I was looking for! I might look some more into exposing VCS tags too, however. On Wed, Feb 22, 2012 at 12:25 PM, Roel van Dijk vandijk.r...@gmail.comwrote: For each package myPackage Cabal generates a module containing, among other things, the package's version as a Haskell value: import Paths_myPackage ( version ) import Data.Version ( showVersion ) main = showVersion version See also Accessing data files from package code in http://www.haskell.org/cabal/users-guide/ I do not now how to expose information from the VCS. 2012/2/22 Eugene Kirpichov ekirpic...@gmail.com: Hi, I'd like my program to print something like this is $program 1.0.4 git 45fea6b when invoked with --version, or at least just the 1.0.4 part. Can Cabal expose the version as a preprocessor macro by default, or do I have to use Build-Type: Custom and add a preprocessing step of my own? -- 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] Inject cabal version or VCS version as a CPP macro
Whoa, I didn't think about using Template Haskell here. Thanks. Perhaps this should be abstracted into a library. On Wed, Feb 22, 2012 at 12:40 PM, Michael Snoyman mich...@snoyman.comwrote: I have a project at work that embeds the Mercurial version in the final executable. I use Template Haskell to call the hg executable and parse its output. Here's the relevant code snippet: putStrLn $ Mercurial commit: ++ $(do let getChangeset s = let (k, v') = break (== ':') s v = dropWhile isSpace $ drop 1 v' in if k == changeset then Just v else Nothing res - qRunIO $ readProcess hg [heads] let cs = mapMaybe getChangeset $ lines res lift $ case cs of x:_ - x [] - unknown) On Wed, Feb 22, 2012 at 10:37 AM, Eugene Kirpichov ekirpic...@gmail.com wrote: Thanks, this is exactly what I was looking for! I might look some more into exposing VCS tags too, however. On Wed, Feb 22, 2012 at 12:25 PM, Roel van Dijk vandijk.r...@gmail.com wrote: For each package myPackage Cabal generates a module containing, among other things, the package's version as a Haskell value: import Paths_myPackage ( version ) import Data.Version ( showVersion ) main = showVersion version See also Accessing data files from package code in http://www.haskell.org/cabal/users-guide/ I do not now how to expose information from the VCS. 2012/2/22 Eugene Kirpichov ekirpic...@gmail.com: Hi, I'd like my program to print something like this is $program 1.0.4 git 45fea6b when invoked with --version, or at least just the 1.0.4 part. Can Cabal expose the version as a preprocessor macro by default, or do I have to use Build-Type: Custom and add a preprocessing step of my own? -- 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 -- 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] Inject cabal version or VCS version as a CPP macro
Hey,
I created a small package:
http://hackage.haskell.org/package/vcs-revision, repo
http://github.com/jkff/vcs-revision
It can be used like this:
{-# LANGUAGE TemplateHaskell #-}
import Distribution.VcsRevision.Git
import Language.Haskell.TH.Syntax
showMyGitVersion :: String
showMyGitVersion = $(do
v - qRunIO getRevision
lift $ case v of
Nothing - none
Just (hash,True) - hash ++ (with local modifications)
Just (hash,False) - hash)
On Wed, Feb 22, 2012 at 2:26 PM, Herbert Valerio Riedel h...@gnu.org wrote:
Hi,
Eugene Kirpichov ekirpic...@gmail.com writes:
I'd like my program to print something like this is $program 1.0.4 git
45fea6b when invoked with --version, or at least just the 1.0.4 part.
Here's some proof-of-concept code we use slightly modified in production
here for over a year now successfully:
https://gist.github.com/656738
The primary goal was to have a reliable version number (allowing to find
the exact corresponding git-commit in the source-code repository), and
to be able to detect when that version number is unreliable (there's
nothing more annoying than wasting time debugging the wrong
source-code...).
The idea is to dynamically infer and overwrite cabal's version when
building from the git repository, and have it accessible via the cabal's
auto-generated Paths_pkg-name module Data.Version...
...and when creating a source-dist, via runghc Setup.hs sdist the
current dynamic git-version string is embedded into the generated
.tar.gz's .cabal file, so that the source-distribution is just a plain
simple .cabal project (that could be uploaded to hackage)
hth,
hvr
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Principal Engineer, Mirantis Inc. http://www.mirantis.com/
Editor, http://fprog.ru/
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Re: [Haskell-cafe] Inject cabal version or VCS version as a CPP macro
On Wed, Feb 22, 2012 at 2:57 PM, Herbert Valerio Riedel h...@gnu.org wrote:
Eugene Kirpichov ekirpic...@gmail.com writes:
It can be used like this:
{-# LANGUAGE TemplateHaskell #-}
import Distribution.VcsRevision.Git
import Language.Haskell.TH.Syntax
showMyGitVersion :: String
showMyGitVersion = $(do
v - qRunIO getRevision
lift $ case v of
Nothing - none
Just (hash,True) - hash ++ (with local modifications)
Just (hash,False) - hash)
Btw, I'm wondering (haven't tried myself), when using TH to generate the
version string, does GHC's and/or cabal's dependency tracking
a) reliably refresh the generated hash so that you can be sure it's
the git-commit id compiled into the binary is reliable, and
b) avoid re-generating the TH file and redundant recompilation if the
git commit-id hasn't changed?
Do you mean all this in the context where this resides in a library rather
than an application? I haven't thought about that yet.
hvr
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Eugene Kirpichov
Principal Engineer, Mirantis Inc. http://www.mirantis.com/
Editor, http://fprog.ru/
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Re: [Haskell-cafe] Hierarchical tracing for debugging laziness
Thanks! I released it: http://hackage.haskell.org/package/htrace http://github.com/jkff/htrace On Wed, Jan 25, 2012 at 4:18 AM, Felipe Almeida Lessa felipe.le...@gmail.com wrote: Really nice! Looks like it could be a useful mini-package on Hackage. -- Felipe. -- 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
[Haskell-cafe] Hierarchical tracing for debugging laziness
Hi cafe,
Look how one can watch the evaluation tree of a computation, to debug
laziness-related problems.
{-# LANGUAGE BangPatterns #-}
module HTrace where
import Data.List (foldl')
import Data.IORef
import System.IO.Unsafe
level = unsafePerformIO $ newIORef 0
htrace str x = unsafePerformIO $ do
lvl - readIORef level
putStrLn (replicate (4*lvl) ' ' ++ str)
writeIORef level (lvl+1)
let !vx = x
writeIORef level lvl
return vx
xs = map (\x - htrace (show x) x) [1..10]
s = foldl (\a b - htrace + (a+b)) 0 xs
s2 = foldl' (\a b - htrace + (a+b)) 0 xs
b = htrace b 2
c = htrace c 3
a = htrace a $ b + c
x = htrace x $ b + c
*HTrace a
a
b
c
5
*HTrace x
x
5
*HTrace s
+
+
+
+
+
+
+
+
+
+
1
2
3
4
5
6
7
8
9
10
55
(reload)
*HTrace s2
+
1
+
2
+
3
+
4
+
5
+
6
+
7
+
8
+
9
+
10
55
--
Eugene Kirpichov
Principal Engineer, Mirantis Inc. http://www.mirantis.com/
Editor, http://fprog.ru/
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Re: [Haskell-cafe] Natural Transformations and fmap
Have you tried generating a free theorem for :- ? (I haven't as I'm writing from my phone) 24.01.2012, в 9:06, Ryan Ingram ryani.s...@gmail.com написал(а): On Mon, Jan 23, 2012 at 8:05 PM, Daniel Fischer daniel.is.fisc...@googlemail.com wrote: On Tuesday 24 January 2012, 04:39:03, Ryan Ingram wrote: At the end of that paste, I prove the three Haskell monad laws from the functor laws and monoid-ish versions of the monad laws, but my proofs all rely on a property of natural transformations that I'm not sure how to prove; given type m :- n = (forall x. m x - n x) class Functor f where fmap :: forall a b. (a - b) - f a - f b -- Functor identity law: fmap id = id -- Functor composition law fmap (f . g) = fmap f . fmap g Given Functors m and n, natural transformation f :: m :- n, and g :: a - b, how can I prove (f . fmap_m g) = (fmap_n g . f)? Unless I'm utterly confused, that's (part of) the definition of a natural transformation (for non-category-theorists). Alright, let's pretend I know nothing about natural transformations and just have the type declaration type m :- n = (forall x. m x - n x) And I have f :: M :- N g :: A - B instance Functor M -- with proofs of functor laws instance Functor N -- with proofs of functor laws How can I prove fmap g. f :: M A - N B = f . fmap g :: M A - N B I assume I need to make some sort of appeal to the parametricity of M :- N. Is there some more fundamental law of natural transformations that I'm not aware of that I need to use? Is it possible to write a natural transformation in Haskell that violates this law? -- ryan ___ 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] Is there a way to do *allocation* profiling with a breakdown by type?
Hi, I've got a program that seems to spend much of its time allocating short-lived objects, which therefore don't show up in +RTS -hy or alike. Is there a way to get a breakdown by type of the objects that are being *allocated* but not necessarily retained (disappear after gen0)? -- 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
[Haskell-cafe] Encouraging performance with ghc 7.4
Hi cafe, Just wanted to inform you that I've been benchmarking my compute-intensive stuff on ghc 7.0.4 vs 7.4.0, and 7.4.0 gave a large speedup - one program that took 2.9s on a particular input is now taking 2.2s. This result is repeatable. So I encourage people to try out GHC 7.4.0. Some stuff may stop compiling (I had to do 3 basically one-line fixes in 3 packages before I got mine to compile), but I didn't encounter other problems. Below is +RTS -s of two runs: one compiled with ghc 7.4.0 and another with 7.0.4. I can make a more detailed comparison if it's useful and if someone tells me how - I thought about including +RTS -p, but Simon Marlow wrote recently that it has started giving meaningful results only in 7.4, so comparison with 7.0.4 would be unfair. However in this case I'm sure that the program is heavily compute-bound by the following two functions (because it's always compute-bound by them): 1) https://github.com/jkff/timeplot/blob/master/Tools/TimePlot/Plots.hs#L226 2) https://github.com/jkff/timeplot/blob/master/Tools/TimePlot/Conf.hs - localToUTC and strptime. jkff@jkff-laptop ~/projects/logs/... $ tplot -if e.trace -dk 'within[.] cumsum 10' -o e.png +RTS -s tplot -if e.trace -dk within[.] cumsum 10 -o e.png +RTS -s 2,751,756,296 bytes allocated in the heap 135,129,112 bytes copied during GC 33,149,720 bytes maximum residency (22 sample(s)) 1,755,868 bytes maximum slop 56 MB total memory in use (0 MB lost due to fragmentation) Generation 0: 4994 collections, 0 parallel, 0.22s, 0.23s elapsed Generation 1:22 collections, 0 parallel, 0.08s, 0.09s elapsed INIT time0.01s ( 0.00s elapsed) MUT time2.61s ( 2.91s elapsed) GCtime0.30s ( 0.32s elapsed) EXIT time0.00s ( 0.00s elapsed) Total time2.91s ( 3.22s elapsed) %GC time 10.1% (9.8% elapsed) Alloc rate1,051,262,083 bytes per MUT second Productivity 89.6% of total user, 80.9% of total elapsed jkff@jkff-laptop ~/projects/logs/... $ tplot -if e.trace -dk 'within[.] cumsum 10' -o e.png +RTS -s 2,161,811,620 bytes allocated in the heap 107,589,660 bytes copied during GC 34,799,400 bytes maximum residency (22 sample(s)) 1,721,152 bytes maximum slop 58 MB total memory in use (0 MB lost due to fragmentation) Tot time (elapsed) Avg pause Max pause Gen 0 3899 colls, 0 par0.13s0.14s 0.s0.0003s Gen 122 colls, 0 par0.08s0.09s 0.0043s0.0482s INITtime0.00s ( 0.00s elapsed) MUT time2.03s ( 2.28s elapsed) GC time0.21s ( 0.23s elapsed) EXITtime0.00s ( 0.00s elapsed) Total time2.26s ( 2.51s elapsed) %GC time 9.3% (9.1% elapsed) Alloc rate1,056,397,390 bytes per MUT second Productivity 90.7% of total user, 81.5% of total elapsed -- 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] Encouraging performance with ghc 7.4
I got even more encouraging results on another input - 5 vs 7 seconds: === GHC 7.4.0 == jkff@jkff-laptop ~/projects/logs/... $ tplot -if lat.trace -dk 'within[.] duration quantile 10 0.25,0.5,0.75,0.9,0.95' -o lat3.png +RTS -s 2,809,230,872 bytes allocated in the heap 358,393,440 bytes copied during GC 42,478,364 bytes maximum residency (68 sample(s)) 1,833,848 bytes maximum slop 113 MB total memory in use (0 MB lost due to fragmentation) Tot time (elapsed) Avg pause Max pause Gen 0 4740 colls, 0 par0.39s0.40s 0.0001s0.0005s Gen 168 colls, 0 par0.42s0.48s 0.0071s0.1157s INITtime0.00s ( 0.00s elapsed) MUT time3.76s ( 4.01s elapsed) GC time0.82s ( 0.88s elapsed) EXITtime0.00s ( 0.00s elapsed) Total time4.59s ( 4.89s elapsed) %GC time 17.8% (18.0% elapsed) Alloc rate744,774,183 bytes per MUT second Productivity 82.2% of total user, 77.2% of total elapsed GHC 7.0.4 === jkff@jkff-laptop ~/projects/logs/... $ tplot -if lat.trace -dk 'within[.] duration quantile 10 0.25,0.5,0.75,0.9,0.95' -o lat3.png +RTS -s tplot -if lat.trace -dk within[.] duration quantile 10 0.25,0.5,0.75,0.9,0.95 -o lat3.png +RTS -s 4,024,048,244 bytes allocated in the heap 419,997,300 bytes copied during GC 44,546,920 bytes maximum residency (70 sample(s)) 1,840,208 bytes maximum slop 113 MB total memory in use (0 MB lost due to fragmentation) Generation 0: 6995 collections, 0 parallel, 0.63s, 0.64s elapsed Generation 1:70 collections, 0 parallel, 0.39s, 0.43s elapsed INIT time0.01s ( 0.00s elapsed) MUT time5.96s ( 6.17s elapsed) GCtime1.02s ( 1.08s elapsed) EXIT time0.00s ( 0.00s elapsed) Total time6.99s ( 7.24s elapsed) %GC time 14.6% (14.9% elapsed) Alloc rate674,478,767 bytes per MUT second Productivity 85.3% of total user, 82.3% of total elapsed On Wed, Jan 18, 2012 at 8:22 PM, Eugene Kirpichov ekirpic...@gmail.comwrote: Hi cafe, Just wanted to inform you that I've been benchmarking my compute-intensive stuff on ghc 7.0.4 vs 7.4.0, and 7.4.0 gave a large speedup - one program that took 2.9s on a particular input is now taking 2.2s. This result is repeatable. So I encourage people to try out GHC 7.4.0. Some stuff may stop compiling (I had to do 3 basically one-line fixes in 3 packages before I got mine to compile), but I didn't encounter other problems. Below is +RTS -s of two runs: one compiled with ghc 7.4.0 and another with 7.0.4. I can make a more detailed comparison if it's useful and if someone tells me how - I thought about including +RTS -p, but Simon Marlow wrote recently that it has started giving meaningful results only in 7.4, so comparison with 7.0.4 would be unfair. However in this case I'm sure that the program is heavily compute-bound by the following two functions (because it's always compute-bound by them): 1) https://github.com/jkff/timeplot/blob/master/Tools/TimePlot/Plots.hs#L226 2) https://github.com/jkff/timeplot/blob/master/Tools/TimePlot/Conf.hs - localToUTC and strptime. jkff@jkff-laptop ~/projects/logs/... $ tplot -if e.trace -dk 'within[.] cumsum 10' -o e.png +RTS -s tplot -if e.trace -dk within[.] cumsum 10 -o e.png +RTS -s 2,751,756,296 bytes allocated in the heap 135,129,112 bytes copied during GC 33,149,720 bytes maximum residency (22 sample(s)) 1,755,868 bytes maximum slop 56 MB total memory in use (0 MB lost due to fragmentation) Generation 0: 4994 collections, 0 parallel, 0.22s, 0.23s elapsed Generation 1:22 collections, 0 parallel, 0.08s, 0.09s elapsed INIT time0.01s ( 0.00s elapsed) MUT time2.61s ( 2.91s elapsed) GCtime0.30s ( 0.32s elapsed) EXIT time0.00s ( 0.00s elapsed) Total time2.91s ( 3.22s elapsed) %GC time 10.1% (9.8% elapsed) Alloc rate1,051,262,083 bytes per MUT second Productivity 89.6% of total user, 80.9% of total elapsed jkff@jkff-laptop ~/projects/logs/... $ tplot -if e.trace -dk 'within[.] cumsum 10' -o e.png +RTS -s 2,161,811,620 bytes allocated in the heap 107,589,660 bytes copied during GC 34,799,400 bytes maximum residency (22 sample(s)) 1,721,152 bytes maximum slop 58 MB total memory in use (0 MB lost due to fragmentation) Tot time (elapsed) Avg pause Max pause Gen 0 3899 colls, 0 par0.13s0.14s 0.s 0.0003s Gen 122 colls, 0 par0.08s0.09s 0.0043s 0.0482s INITtime0.00s ( 0.00s elapsed) MUT time2.03s ( 2.28s elapsed) GC time0.21s ( 0.23s elapsed
[Haskell-cafe] __GLASGOW_HASKELL__ for GHC 7.4
Hi, I'm fixing a build error in a package that depends on the RTS API, which changed in 7.4, using #if __GLASGOW_HASKELL__ = 740. However, build log shows that __GLASGOW_HASKELL__ is still 704, not 740 as I'd expect. Is this a bug? -- 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] __GLASGOW_HASKELL__ for GHC 7.4
My bad, it *should* really be 704. http://www.haskell.org/ghc/docs/latest/html/users_guide/options-phases.html#c-pre-processor On Tue, Jan 17, 2012 at 3:35 PM, Eugene Kirpichov ekirpic...@gmail.comwrote: Hi, I'm fixing a build error in a package that depends on the RTS API, which changed in 7.4, using #if __GLASGOW_HASKELL__ = 740. However, build log shows that __GLASGOW_HASKELL__ is still 704, not 740 as I'd expect. Is this a bug? -- Eugene Kirpichov Principal Engineer, Mirantis Inc. http://www.mirantis.com/ Editor, http://fprog.ru/ -- 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] GHC exceeding command line length limit with split-objs - and a possible fix
Thanks, looks like I already succeeded by downloading xcode 3. Now my original question remains - is such a change a good idea? (I've already found the place in code where the fix has to be made; should take an hour of work at most) On Wed, Jan 11, 2012 at 6:07 PM, Hans Aberg haber...@telia.com wrote: On 11 Jan 2012, at 13:38, John Lato wrote: I used https://github.com/kennethreitz/osx-gcc-installer/downloads to get a real gcc on Lion. Biggish download, but it worked. I've also seen reports of success by self-compiling gcc, or by installing XCode 4 on top of an existing XCode 3 installation. GCC 4.6.2 builds on OS X 10.7 with Xcode 4.2. Build GMP 5.0.2 with clang, and then GCC with /usr/bin/gcc - llvm-gcc-4.2. I think I saw someone guild GCC 4.7, but this is highest stable. Hans From: Eugene Kirpichov ekirpic...@gmail.com Oh well... looks like building ghc won't be easy, as it doesn't build with llvm-gcc and it's not easy to get a real gcc on Lion. But I don't stop trying :) -- 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] GHC exceeding command line length limit with split-objs - and a possible fix
Hi Brandon, Thanks - looks like this would be a modification of the linking stage, splitting it into two parts: batching objects and then actually linking them. Do you think that what I originally proposed is still a good thing to have before implementing your solution? (it definitely would be for myself, as it's easier to do and I'd then quicker become able to build my application with split-objs and shrink its executable size from 11 to 2Mb) On Wed, Jan 11, 2012 at 9:48 PM, Brandon Allbery allber...@gmail.comwrote: On Wed, Jan 11, 2012 at 02:12, Eugene Kirpichov ekirpic...@gmail.comwrote: I think a nice fix would be to employ gcc's ability to read options from a file - gcc @file - and write overly long option strings into temp files. What immediately occurs to me is, what if the problem (or another manifestation of same) occurs in the ld step? OS X's ld(1) doesn't have such an option /per se/, and binutils ld(1) does not reliably create valid Mach-O objects. I would consider batching split-objs files into static archives (see ar(1) and ranlib(1)). This also has the advantages of being portable (other platforms other have length limits; I believe it's the main reason split-objs is disabled by default on e.g. Solaris) and that with many linkers it's faster than individual objects because it can use the archive table of contents to speed up searching for files and symbols. -- brandon s allbery allber...@gmail.com wandering unix systems administrator (available) (412) 475-9364 vm/sms -- 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
[Haskell-cafe] GHC exceeding command line length limit with split-objs - and a possible fix
Hi, I'm building gtk2hs on a mac with -fsplit-objs, and during compilation of the largest file, which produces about 7000 split objects, the linking phase fails. I'm assuming that's because the command line length has been exceeded, because other files compile fine, without -fsplit-objs it compiles fine too, and it compiles fine *with* -fsplit-objs on other OS - so perhaps the reason is in mac's tempfile name generation (they're longer than on other platforms) or something. Anyway. I think a nice fix would be to employ gcc's ability to read options from a file - gcc @file - and write overly long option strings into temp files. It'd be fun for me to implement this as my first contribution to ghc; is this a good idea in general? -- 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] GHC exceeding command line length limit with split-objs - and a possible fix
Oh well... looks like building ghc won't be easy, as it doesn't build with llvm-gcc and it's not easy to get a real gcc on Lion. But I don't stop trying :) On Wed, Jan 11, 2012 at 11:12 AM, Eugene Kirpichov ekirpic...@gmail.comwrote: Hi, I'm building gtk2hs on a mac with -fsplit-objs, and during compilation of the largest file, which produces about 7000 split objects, the linking phase fails. I'm assuming that's because the command line length has been exceeded, because other files compile fine, without -fsplit-objs it compiles fine too, and it compiles fine *with* -fsplit-objs on other OS - so perhaps the reason is in mac's tempfile name generation (they're longer than on other platforms) or something. Anyway. I think a nice fix would be to employ gcc's ability to read options from a file - gcc @file - and write overly long option strings into temp files. It'd be fun for me to implement this as my first contribution to ghc; is this a good idea in general? -- Eugene Kirpichov Principal Engineer, Mirantis Inc. http://www.mirantis.com/ Editor, http://fprog.ru/ -- 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
[Haskell-cafe] All the random packages
Hi, I came across the beautiful algorithm for O(1) generation of rational discrete distributions http://www.keithschwarz.com/darts-dice-coins/ and though it'd be fun to implement it in Haskell and put on Hackage, but then it turned out that there's about a dozen random number packages, so I'm not sure to which one to contribute, or better to roll out my own package and encourage authors of the other packages to reference it and fit under their interface. What do you think? Which random number packages are considered to be most mature or perhaps promising - i.e., contributing to which ones will bring the community the most benefit? Is there any effort on unifying them going on? -- 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] Type class for sequences with dependent types
Will this help?
data List a b where
List :: [a] - List a a
05.01.2012, в 17:12, Robbert Krebbers mailingli...@robbertkrebbers.nl
написал(а):
Hello,
in a Haskell development I have to represent paths that have elements of
alternating types. GADTs allow me to do this easily:
data AltList :: * - * - * where
Nil :: AltList a a
ICons :: Int - AltList Int b - AltList () b
UCons :: () - AltList () b - AltList Int b
Since I have various kinds of these data structures I defined a type class
for common operations on such data structures.
class DepSequence l where
nil :: l a a
app :: l a b - l b c - l a c
The instance for AltList is as follows:
instance DepSequence AltList where
nil = Nil
Nil `app` k = k
ICons i l `app` k = ICons i (l `app` k)
UCons i l `app` k = UCons i (l `app` k)
This all works nicely, however, I also want ordinary lists to be an instance
of this class too. I tried the following:
type IntListAlt a b = [Int]
instance DepSequence IntListAlt where
nil = []
app = (++)
But GHC does not like this, it yields:
Type synonym `IntListAlt' should have 2 arguments, but has been
given none In the instance declaration for `DepList IntListAlt'
The following alternative works, but it is quite ugly
newtype IntList a b = IntList { getList :: [Int] }
instance DepSequence IntList where
nil = IntList []
app l k = IntList (getList l ++ getList k)
and also does not give me a nil of type [Int] and an app of type [Int] -
[Int] - [Int].
Does anyone know whether Haskell allows me to do this in a better way?
Best,
Robbert
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Re: [Haskell-cafe] Reifying case expressions [was: Re: On stream processing, and a new release of timeplot coming]
2011/12/26 Gábor Lehel illiss...@gmail.com On Sun, Dec 25, 2011 at 9:19 PM, Eugene Kirpichov ekirpic...@gmail.com wrote: Hello Heinrich, Thanks, that's sure some food for thought! A few notes: * This is indeed analogous to Iteratees. I tried doing the same with Iteratees but failed, so I decided to put together something simple of my own. * The Applicative structure over this stuff is very nice. I was thinking, what structure to put on - and Applicative seems the perfect fit. It's also possible to implement Arrows - but I once tried and failed; however, I was trying that for a more complex stream transformer datatype (a hybrid of Iteratee and Enumerator). * StreamSummary is trivially a bifunctor. I actually wanted to make it an instance of Bifunctor, but it was in the category-extras package and I hesitated to reference this giant just for this purpose :) Probably bifunctors should be in prelude. Edward Kmett has been splitting that up into a variety of smaller packages, for instance: http://hackage.haskell.org/package/bifunctors Actually it's not a bifunctor - it's a functor in one argument and contrafunctor in the other. Is there a name for such a structure? * Whereas StreamSummary a r abstracts deconstruction of lists, the dual datatype (StreamSummary a r -) abstracts construction; however I just now (after looking at your first definition of length) understood that it is trivially isomorphic to the regular list datatype - you just need to be non-strict in the state - listify :: ListTo a [a] = CaseOf [] (\x - fmap (x:) listify). So you don't need functions of the form (forall r . ListTo a r - ListTo b r) - you just need (ListTo b [a]). This is a revelation for me. On Sun, Dec 25, 2011 at 2:25 PM, Heinrich Apfelmus apfel...@quantentunnel.de wrote: Eugene Kirpichov wrote: In the last couple of days I completed my quest of making my graphing utility timeplot ( http://jkff.info/software/timeplotters ) not load the whole input dataset into memory and consequently be able to deal with datasets of any size, provided however that the amount of data to *draw* is not so large. On the go it also got a huge speedup - previously visualizing a cluster activity dataset with a million events took around 15 minutes and a gig of memory, now it takes 20 seconds and 6 Mb max residence. (I haven't yet uploaded to hackage as I have to give it a bit more testing) The refactoring involved a number of interesting programming patterns that I'd like to share with you and ask for feedback - perhaps something can be simplified. The source is at http://github.com/jkff/timeplot The datatype of incremental computations is at https://github.com/jkff/timeplot/blob/master/Tools/TimePlot/Incremental.hs. Strictness is extremely important here - the last memory leak I eliminated was lack of bang patterns in teeSummary. Your StreamSummary type has a really nice interpretation: it's a reification of case expressions. For instance, consider the following simple function from lists to integers length :: [a] - Int length xs = case xs of [] - 0 (y:ys) - 1 + length ys We want to reify the case expression as constructor of a data type. What type should it have? Well, a case expression maps a list xs to a result, here of type Int, via two cases: the first case gives a result and the other maps a value of type a to a function from lists to results again. This explanation was probably confusing, so I'll just go ahead and define a data type that represents functions from lists [a] to some result of type r data ListTo a r = CaseOf r (a - ListTo a r) interpret :: ListTo a r - ([a] - r) interpret (CaseOf nil cons) xs = case xs of [] - nil (y:ys) - interpret (cons y) ys As you can see, we are just mapping each CaseOf constructor back to a built-in case expression. Likewise, each function from lists can be represented in terms of our new data type: simply replace all built-in case expressions with the new constructor length' :: ListTo a Int length' = CaseOf (0) (\x - fmap (1+) length') length = interpret length' The CaseOf may look a bit weird, but it's really just a straightforward translation of the case expression you would use to define the function go instead. Ok, this length function is really inefficient because it builds a huge expression of the form (1+(1+...)). Let's implement a strict variant instead lengthL :: ListTo a Int lengthL = go 0 where go !n = CaseOf (n) (\x - go (n+1)) While we're at it, let's translate two more list functions foldL' :: (b - a - b) - b - ListTo a b foldL' f b = Case b (\a - foldL' f $! f b a) sumL:: ListTo Int Int sumL
[Haskell-cafe] Convert Double to Data.Fixed
Hi cafe, How do I most efficiently convert a Double to a Data.Fixed? I'm asking because I want to convert fractional seconds to the seconds field of Data.Time.TimeOfDay, which is Pico = Data.Fixed.Fixed E12. For now the fastest thing I came up with was fromIntegral (round (sec*100)) / fromIntegral 100, but this frankly sucks and is rather slow, there must be a better way. -- 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] Reifying case expressions [was: Re: On stream processing, and a new release of timeplot coming]
Whoa. Sebastian, you're my hero — I've been struggling with defining Arrow for ListTransformer for a substantial time without success, and here you got it, dramatically simpler than I thought it could be done (I was using explicit queues). I wonder if now this datatype of yours is isomorphic to StreamSummary b r - StreamSummary a r. 26.12.2011, в 19:56, Sebastian Fischer fisc...@nii.ac.jp написал(а): On Sun, Dec 25, 2011 at 11:25 AM, Heinrich Apfelmus apfel...@quantentunnel.de wrote: Your StreamSummary type has a really nice interpretation: it's a reification of case expressions [on lists]. nice observation! For instance, consider the following simple function from lists to integers length :: [a] - Int length xs = case xs of [] - 0 (y:ys) - 1 + length ys We want to reify the case expression as constructor of a data type. [...] data ListTo a r = CaseOf r (a - ListTo a r) interpret :: ListTo a r - ([a] - r) interpret (CaseOf nil cons) xs = case xs of [] - nil (y:ys) - interpret (cons y) ys [...] Likewise, each function from lists can be represented in terms of our new data type [...] length' :: ListTo a Int length' = CaseOf (0) (\x - fmap (1+) length') length = interpret length' This version of `length` is tail recursive while the previous version is not. In general, all functions defined in terms of `ListTo` and `interpret` are spine strict - they return a result only after consuming all input list constructors. This is what Eugene observed when defining the identity function as idC = CaseOf [] (\x - (x:) $ idC) This version does not work for infinite lists. Similarly, `head` and `take` cannot be defined as lazily as in the standard libraries. We can support lazier list consumers by adding a case to the ListTo type that allows to stop consuming the list. To avoid confusion, I chose new names for my new types. data ListConsumer a b = Done !b | Continue !b (a - ListConsumer a b) The interpretation function just ignores the remaining input in the case of `Done`: consumeList :: ListConsumer a b - [a] - b consumeList (Done b) _ = b consumeList (Continue b _) [] = b consumeList (Continue _ f) (x:xs) = consumeList (f x) xs We can define lazier versions of `head` and `take` as follows: headC :: ListConsumer a a headC = Continue (error head of empty list) Done takeC :: Int - ListConsumer a [a] takeC 0 = Done [] takeC n = Continue [] (\x - (x:) $ takeC (n-1)) However, we still cannot define a lazy version of the identity funtion with list consumers. The identity function and `takeC` belong to a special case of a list consumers because they also *produce* lists. We can define a specialized type for list transformers that consume and produce lists. One advantage of this specialization will be that we can define a lazy version of the identity function. The transformer type can have functor and applicative instances similar to the consumer type to compose transformers in parallel. Additionally, it can have category and arrow instances to compose transformers sequentially. Here is a type for lazy list transformers: data ListTransformer a b = Cut | Put b (ListTransformer a b) | Get (a - ListTransformer a b) A transformer can either cut off the input list and return the empty list, output a new element before transforming the input, or consume one element from the input list and transform the remaining elements. The interpretation function should make this clearer: transformList :: ListTransformer a b - [a] - [b] transformList Cut _ = [] transformList (Put b t) xs = b : transformList t xs transformList (Get _) [] = [] transformList (Get f) (x:xs) = transformList (f x) xs Note that, if the transformer wants to read another element that is not there, it simply returns the empty list. Now we can define a lazy identity function and another version of `take`: idT :: ListTransformer a a idT = Get (\x - Put x idT) takeT :: Int - ListTransformer a a takeT 0 = Cut takeT n = Get (\x - Put x (takeT (n-1))) Here is another translation of a common list function: filterT :: (a - Bool) - ListTransformer a a filterT p = Get (\x - if p x then Put x (filterT p) else filterT p) `filterT` is an example for a function that can consume several input elements before producing an output element. Other examples for functions of this kind are chunking functions: pairsT :: ListTransformer a (a,a) pairsT = Get (\x - Get (\y - Put (x,y) pairsT)) chunks :: Int - ListTransformer a [a] chunks n = collect n where collect 0 = Put [] (chunks n) collect m = Get (\x -
Re: [Haskell-cafe] Reifying case expressions [was: Re: On stream processing, and a new release of timeplot coming]
On Tue, Dec 27, 2011 at 7:23 AM, Sebastian Fischer fisc...@nii.ac.jpwrote: 2011/12/26 Eugene Kirpichov ekirpic...@gmail.com Whoa. Sebastian, you're my hero — I've been struggling with defining Arrow for ListTransformer for a substantial time without success, and here you got it, dramatically simpler than I thought it could be done (I was using explicit queues). This stuff is tricky. I noticed that my Applicative instance did not satisfy all required laws. I think I could fix this by changing the implementation of pure to pure x = Put x $ pure x in analogy to the ZipList instance. At least, QuickCheck does not complain anymore (I did not write proofs). The original definition of `pure` was inspired by Chris Smith's post on the connection of Category/Applicative and Arrow: http://cdsmith.wordpress.com/2011/08/13/arrow-category-applicative-part-iia/ However, even with the fixed Applicative instance, the Arrow instance does not satisfy all laws. ListTransformer seems to be a type that has valid Category and Applicative instances which do not give rise to a valid Arrow instance as outlined by Chris. One of his additional axioms relating Category and Applicative does not hold. I have extended the (corrected) code with QuickCheck tests: https://gist.github.com/1521467 Thanks, I'll take a look. I wonder if now this datatype of yours is isomorphic to StreamSummary b r - StreamSummary a r. Not sure what you mean here. StreamSummary seems to be the same as ListConsumer but I don't see how functions from consumers to consumers are list transformers, i.e., functions from lists to lists. Well. They are isomorphic, if list transformers are represented as functions from lists. I'm assuming they could be with the other representation too. type ListT a b = forall r . ([b] - r) - ([a] - r) there :: ([a] - [b]) - ListT a b there as2bs bs2r = bs2r . as2bs back :: ListT a b - ([a] - [b]) back f = f id Sebastian -- 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] Reifying case expressions [was: Re: On stream processing, and a new release of timeplot coming]
Hello Heinrich, Thanks, that's sure some food for thought! A few notes: * This is indeed analogous to Iteratees. I tried doing the same with Iteratees but failed, so I decided to put together something simple of my own. * The Applicative structure over this stuff is very nice. I was thinking, what structure to put on - and Applicative seems the perfect fit. It's also possible to implement Arrows - but I once tried and failed; however, I was trying that for a more complex stream transformer datatype (a hybrid of Iteratee and Enumerator). * StreamSummary is trivially a bifunctor. I actually wanted to make it an instance of Bifunctor, but it was in the category-extras package and I hesitated to reference this giant just for this purpose :) Probably bifunctors should be in prelude. * Whereas StreamSummary a r abstracts deconstruction of lists, the dual datatype (StreamSummary a r -) abstracts construction; however I just now (after looking at your first definition of length) understood that it is trivially isomorphic to the regular list datatype - you just need to be non-strict in the state - listify :: ListTo a [a] = CaseOf [] (\x - fmap (x:) listify). So you don't need functions of the form (forall r . ListTo a r - ListTo b r) - you just need (ListTo b [a]). This is a revelation for me. On Sun, Dec 25, 2011 at 2:25 PM, Heinrich Apfelmus apfel...@quantentunnel.de wrote: Eugene Kirpichov wrote: In the last couple of days I completed my quest of making my graphing utility timeplot ( http://jkff.info/software/**timeplottershttp://jkff.info/software/timeplotters) not load the whole input dataset into memory and consequently be able to deal with datasets of any size, provided however that the amount of data to *draw* is not so large. On the go it also got a huge speedup - previously visualizing a cluster activity dataset with a million events took around 15 minutes and a gig of memory, now it takes 20 seconds and 6 Mb max residence. (I haven't yet uploaded to hackage as I have to give it a bit more testing) The refactoring involved a number of interesting programming patterns that I'd like to share with you and ask for feedback - perhaps something can be simplified. The source is at http://github.com/jkff/**timeplothttp://github.com/jkff/timeplot The datatype of incremental computations is at https://github.com/jkff/**timeplot/blob/master/Tools/** TimePlot/Incremental.hshttps://github.com/jkff/timeplot/blob/master/Tools/TimePlot/Incremental.hs. Strictness is extremely important here - the last memory leak I eliminated was lack of bang patterns in teeSummary. Your StreamSummary type has a really nice interpretation: it's a reification of case expressions. For instance, consider the following simple function from lists to integers length :: [a] - Int length xs = case xs of [] - 0 (y:ys) - 1 + length ys We want to reify the case expression as constructor of a data type. What type should it have? Well, a case expression maps a list xs to a result, here of type Int, via two cases: the first case gives a result and the other maps a value of type a to a function from lists to results again. This explanation was probably confusing, so I'll just go ahead and define a data type that represents functions from lists [a] to some result of type r data ListTo a r = CaseOf r (a - ListTo a r) interpret :: ListTo a r - ([a] - r) interpret (CaseOf nil cons) xs = case xs of [] - nil (y:ys) - interpret (cons y) ys As you can see, we are just mapping each CaseOf constructor back to a built-in case expression. Likewise, each function from lists can be represented in terms of our new data type: simply replace all built-in case expressions with the new constructor length' :: ListTo a Int length' = CaseOf (0) (\x - fmap (1+) length') length = interpret length' The CaseOf may look a bit weird, but it's really just a straightforward translation of the case expression you would use to define the function go instead. Ok, this length function is really inefficient because it builds a huge expression of the form (1+(1+...)). Let's implement a strict variant instead lengthL :: ListTo a Int lengthL = go 0 where go !n = CaseOf (n) (\x - go (n+1)) While we're at it, let's translate two more list functions foldL' :: (b - a - b) - b - ListTo a b foldL' f b = Case b (\a - foldL' f $! f b a) sumL:: ListTo Int Int sumL= foldL' (\b a - a+b) 0 And now we can go for the point of this message: unlike ordinary functions from lists, we can compose these in lock-step! In particular, the following applicative instance instance Applicative (ListTo a) where pure b = CaseOf b (const $ pure b) (CaseOf f fs) * (CaseOf x xs) = CaseOf (f x) (\a - fs a * xs a) allows us to write a function
Re: [Haskell-cafe] Reifying case expressions [was: Re: On stream processing, and a new release of timeplot coming]
On Mon, Dec 26, 2011 at 12:19 AM, Eugene Kirpichov ekirpic...@gmail.comwrote: Hello Heinrich, Thanks, that's sure some food for thought! A few notes: * This is indeed analogous to Iteratees. I tried doing the same with Iteratees but failed, so I decided to put together something simple of my own. * The Applicative structure over this stuff is very nice. I was thinking, what structure to put on - and Applicative seems the perfect fit. It's also possible to implement Arrows - but I once tried and failed; however, I was trying that for a more complex stream transformer datatype (a hybrid of Iteratee and Enumerator). * StreamSummary is trivially a bifunctor. I actually wanted to make it an instance of Bifunctor, but it was in the category-extras package and I hesitated to reference this giant just for this purpose :) Probably bifunctors should be in prelude. * Whereas StreamSummary a r abstracts deconstruction of lists, the dual datatype (StreamSummary a r -) abstracts construction; however I just now (after looking at your first definition of length) understood that it is trivially isomorphic to the regular list datatype - you just need to be non-strict in the state - listify :: ListTo a [a] = CaseOf [] (\x - fmap (x:) listify). So you don't need functions of the form (forall r . ListTo a r - ListTo b r) - you just need (ListTo b [a]). This is a revelation for me. Oops, this is wrong! You cannot create a working listify that would produce the list [1..] when applied to the list [1..]. So production of elements also needs to be explicitly abstracted by the dual type. On Sun, Dec 25, 2011 at 2:25 PM, Heinrich Apfelmus apfel...@quantentunnel.de wrote: Eugene Kirpichov wrote: In the last couple of days I completed my quest of making my graphing utility timeplot ( http://jkff.info/software/**timeplottershttp://jkff.info/software/timeplotters) not load the whole input dataset into memory and consequently be able to deal with datasets of any size, provided however that the amount of data to *draw* is not so large. On the go it also got a huge speedup - previously visualizing a cluster activity dataset with a million events took around 15 minutes and a gig of memory, now it takes 20 seconds and 6 Mb max residence. (I haven't yet uploaded to hackage as I have to give it a bit more testing) The refactoring involved a number of interesting programming patterns that I'd like to share with you and ask for feedback - perhaps something can be simplified. The source is at http://github.com/jkff/**timeplothttp://github.com/jkff/timeplot The datatype of incremental computations is at https://github.com/jkff/**timeplot/blob/master/Tools/** TimePlot/Incremental.hshttps://github.com/jkff/timeplot/blob/master/Tools/TimePlot/Incremental.hs. Strictness is extremely important here - the last memory leak I eliminated was lack of bang patterns in teeSummary. Your StreamSummary type has a really nice interpretation: it's a reification of case expressions. For instance, consider the following simple function from lists to integers length :: [a] - Int length xs = case xs of [] - 0 (y:ys) - 1 + length ys We want to reify the case expression as constructor of a data type. What type should it have? Well, a case expression maps a list xs to a result, here of type Int, via two cases: the first case gives a result and the other maps a value of type a to a function from lists to results again. This explanation was probably confusing, so I'll just go ahead and define a data type that represents functions from lists [a] to some result of type r data ListTo a r = CaseOf r (a - ListTo a r) interpret :: ListTo a r - ([a] - r) interpret (CaseOf nil cons) xs = case xs of [] - nil (y:ys) - interpret (cons y) ys As you can see, we are just mapping each CaseOf constructor back to a built-in case expression. Likewise, each function from lists can be represented in terms of our new data type: simply replace all built-in case expressions with the new constructor length' :: ListTo a Int length' = CaseOf (0) (\x - fmap (1+) length') length = interpret length' The CaseOf may look a bit weird, but it's really just a straightforward translation of the case expression you would use to define the function go instead. Ok, this length function is really inefficient because it builds a huge expression of the form (1+(1+...)). Let's implement a strict variant instead lengthL :: ListTo a Int lengthL = go 0 where go !n = CaseOf (n) (\x - go (n+1)) While we're at it, let's translate two more list functions foldL' :: (b - a - b) - b - ListTo a b foldL' f b = Case b (\a - foldL' f $! f b a) sumL:: ListTo Int Int sumL= foldL' (\b a - a+b) 0 And now we can go for the point of this message: unlike
Re: [Haskell-cafe] strict, lazy, non-strict, eager
I applaud the pedantry, but I must admit that the tone of the original email is unusually harsh for the Haskell community, even though not so harsh as to really make me (for example) scared. On Sat, Dec 24, 2011 at 12:47 PM, Murray Campbell mur...@sonology.netwrote: On Sat, Dec 24, 2011 at 08:54:43AM +0100, Yves Parès wrote: See that's typically the speech that scares people away from Haskell... -- The ⥠is a lie. 2011/12/24 Albert Y. C. Lai [1]tre...@vex.net [ snip. ] I find this sort of discussion is precisely what draws me to, and keeps me in pursuit of Haskell. There are many approaches to producing code that are designed (to use a charitable term) to be minimally frightening at the expense of rigour. The dogged and uncompromising attitude of many in the Haskell community is inspiring to me, knowing as I do that, while I don't *need* to follow the more rarified flights of mathematical fancy to get things done, the ecosystem in which I am choosing to work is being built by those who can. It's not as though the problem of writing good code has been solved. It appears to be quite hard! Isn't Haskell the place where the difficult and nit-picky questions ought to be raised and researched? It's too late to avoid success at all costs but please don't banish our precious pedantry! Scare on! Murray Campbell ___ 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] Parallel Karatsuba - A Weird speed up value greater than 4 on an Intel Quadcore CPU!
Superlinear speedup can occur due to the increased cache size. 24.12.2011, в 19:49, Burak Ekici ekcbu...@hotmail.com написал(а): Dear List, I am trying to parallelize Karatsuba multiplication with Haskell's second generation strategies. Although, I am running the code on an Intel quad-core CPU, I abnormally have a speedup much greater than 4, around 10, which means a weird parallelization or something occurs. I would be appreciated, if anyone make some comments on the issue explaining the possible reasons why this weird incident occurs? Here is the basic parallel portion of the code: karatsuba :: Int - [Bool] - [Bool] - [Bool] karatsuba _ [] _ = [] karatsuba _ _ [] = [] karatsuba currentDepth xs ys | (l 32 || currentDepth = limit) = mul xs ys | otherwise = (x `add` (replicate l False ++ (z `add` (replicate l False ++ y `Main.using` strategy where l = (min (length xs) (length ys)) `div` 2 (xs0, xs1) = splitAt l xs (ys0, ys1) = splitAt l ys x = (normalize (karatsuba (currentDepth+1) xs0 ys0)) y = (normalize (karatsuba (currentDepth+1) xs1 ys1)) z = ((karatsuba (currentDepth+1) (add xs0 xs1) (add ys0 ys1)) `sub` (normalize (karatsuba (currentDepth+1) xs0 ys0)) `sub` (normalize (karatsuba (currentDepth+1) xs1 ys1))) strategy res = do (Main.rpar) (x) (Main.rpar) (y) (Main.rpar) (z) Main.rdeepseq res Many thanks in advance and kind regards. Saluti, Burak. ___ 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
Re: [Haskell-cafe] Parallel Karatsuba - A Weird speed up value greater than 4 on an Intel Quadcore CPU!
Well, assume that cache is x times faster than main memory and that the hot working set size is y, and cache size of one core is z, and that the algorithm is really bound by memory access. Then some simple math should give the answer :) I can't do it myself now as I don't have a pen and paper at the moment. 24.12.2011, в 19:58, Burak Ekici ekcbu...@hotmail.com написал(а): First of all, thanks a lot for your quick answer! However, the question is what are the approximate limits of this super-linear speedup? I mean, is it acceptable, if parallelization happens even 100 time faster? How can I calculate the limits of this speedup via the cache size of my processor? Cheers, Burak. CC: haskell-cafe@haskell.org From: ekirpic...@gmail.com Subject: Re: [Haskell-cafe] Parallel Karatsuba - A Weird speed up value greater than 4 on an Intel Quadcore CPU! Date: Sat, 24 Dec 2011 19:53:26 +0400 To: ekcbu...@hotmail.com Superlinear speedup can occur due to the increased cache size. 24.12.2011, в 19:49, Burak Ekici ekcbu...@hotmail.com написал(а): Dear List, I am trying to parallelize Karatsuba multiplication with Haskell's second generation strategies. Although, I am running the code on an Intel quad-core CPU, I abnormally have a speedup much greater than 4, around 10, which means a weird parallelization or something occurs. I would be appreciated, if anyone make some comments on the issue explaining the possible reasons why this weird incident occurs? Here is the basic parallel portion of the code: karatsuba :: Int - [Bool] - [Bool] - [Bool] karatsuba _ [] _ = [] karatsuba _ _ [] = [] karatsuba currentDepth xs ys | (l 32 || currentDepth = limit) = mul xs ys | otherwise = (x `add` (replicate l False ++ (z `add` (replicate l False ++ y `Main.using` strategy where l = (min (length xs) (length ys)) `div` 2 (xs0, xs1) = splitAt l xs (ys0, ys1) = splitAt l ys x = (normalize (karatsuba (currentDepth+1) xs0 ys0)) y = (normalize (karatsuba (currentDepth+1) xs1 ys1)) z = ((karatsuba (currentDepth+1) (add xs0 xs1) (add ys0 ys1)) `sub` (normalize (karatsuba (currentDepth+1) xs0 ys0)) `sub` (normalize (karatsuba (currentDepth+1) xs1 ys1))) strategy res = do (Main.rpar) (x) (Main.rpar) (y) (Main.rpar) (z) Main.rdeepseq res Many thanks in advance and kind regards. Saluti, Burak. ___ 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
Re: [Haskell-cafe] Parallel Karatsuba - A Weird speed up value greater than 4 on an Intel Quadcore CPU!
If the cache was infinitely faster, then doubling it would give an infinite speedup for an algorithm whose working set was exactly one core's cache size. 24.12.2011, в 19:58, Burak Ekici ekcbu...@hotmail.com написал(а): First of all, thanks a lot for your quick answer! However, the question is what are the approximate limits of this super-linear speedup? I mean, is it acceptable, if parallelization happens even 100 time faster? How can I calculate the limits of this speedup via the cache size of my processor? Cheers, Burak. CC: haskell-cafe@haskell.org From: ekirpic...@gmail.com Subject: Re: [Haskell-cafe] Parallel Karatsuba - A Weird speed up value greater than 4 on an Intel Quadcore CPU! Date: Sat, 24 Dec 2011 19:53:26 +0400 To: ekcbu...@hotmail.com Superlinear speedup can occur due to the increased cache size. 24.12.2011, в 19:49, Burak Ekici ekcbu...@hotmail.com написал(а): Dear List, I am trying to parallelize Karatsuba multiplication with Haskell's second generation strategies. Although, I am running the code on an Intel quad-core CPU, I abnormally have a speedup much greater than 4, around 10, which means a weird parallelization or something occurs. I would be appreciated, if anyone make some comments on the issue explaining the possible reasons why this weird incident occurs? Here is the basic parallel portion of the code: karatsuba :: Int - [Bool] - [Bool] - [Bool] karatsuba _ [] _ = [] karatsuba _ _ [] = [] karatsuba currentDepth xs ys | (l 32 || currentDepth = limit) = mul xs ys | otherwise = (x `add` (replicate l False ++ (z `add` (replicate l False ++ y `Main.using` strategy where l = (min (length xs) (length ys)) `div` 2 (xs0, xs1) = splitAt l xs (ys0, ys1) = splitAt l ys x = (normalize (karatsuba (currentDepth+1) xs0 ys0)) y = (normalize (karatsuba (currentDepth+1) xs1 ys1)) z = ((karatsuba (currentDepth+1) (add xs0 xs1) (add ys0 ys1)) `sub` (normalize (karatsuba (currentDepth+1) xs0 ys0)) `sub` (normalize (karatsuba (currentDepth+1) xs1 ys1))) strategy res = do (Main.rpar) (x) (Main.rpar) (y) (Main.rpar) (z) Main.rdeepseq res Many thanks in advance and kind regards. Saluti, Burak. ___ 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
Re: [Haskell-cafe] Parallel Karatsuba - A Weird speed up value greater than 4 on an Intel Quadcore CPU!
I mean exactly 2x one cores cache size of course. 24.12.2011, в 20:06, Eugene Kirpichov ekirpic...@gmail.com написал(а): If the cache was infinitely faster, then doubling it would give an infinite speedup for an algorithm whose working set was exactly one core's cache size. 24.12.2011, в 19:58, Burak Ekici ekcbu...@hotmail.com написал(а): First of all, thanks a lot for your quick answer! However, the question is what are the approximate limits of this super-linear speedup? I mean, is it acceptable, if parallelization happens even 100 time faster? How can I calculate the limits of this speedup via the cache size of my processor? Cheers, Burak. CC: haskell-cafe@haskell.org From: ekirpic...@gmail.com Subject: Re: [Haskell-cafe] Parallel Karatsuba - A Weird speed up value greater than 4 on an Intel Quadcore CPU! Date: Sat, 24 Dec 2011 19:53:26 +0400 To: ekcbu...@hotmail.com Superlinear speedup can occur due to the increased cache size. 24.12.2011, в 19:49, Burak Ekici ekcbu...@hotmail.com написал(а): Dear List, I am trying to parallelize Karatsuba multiplication with Haskell's second generation strategies. Although, I am running the code on an Intel quad-core CPU, I abnormally have a speedup much greater than 4, around 10, which means a weird parallelization or something occurs. I would be appreciated, if anyone make some comments on the issue explaining the possible reasons why this weird incident occurs? Here is the basic parallel portion of the code: karatsuba :: Int - [Bool] - [Bool] - [Bool] karatsuba _ [] _ = [] karatsuba _ _ [] = [] karatsuba currentDepth xs ys | (l 32 || currentDepth = limit) = mul xs ys | otherwise = (x `add` (replicate l False ++ (z `add` (replicate l False ++ y `Main.using` strategy where l = (min (length xs) (length ys)) `div` 2 (xs0, xs1) = splitAt l xs (ys0, ys1) = splitAt l ys x = (normalize (karatsuba (currentDepth+1) xs0 ys0)) y = (normalize (karatsuba (currentDepth+1) xs1 ys1)) z = ((karatsuba (currentDepth+1) (add xs0 xs1) (add ys0 ys1)) `sub` (normalize (karatsuba (currentDepth+1) xs0 ys0)) `sub` (normalize (karatsuba (currentDepth+1) xs1 ys1))) strategy res = do (Main.rpar) (x) (Main.rpar) (y) (Main.rpar) (z) Main.rdeepseq res Many thanks in advance and kind regards. Saluti, Burak. ___ 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
Re: [Haskell-cafe] strict, lazy, non-strict, eager
On Sat, Dec 24, 2011 at 10:49 PM, Dan Doel dan.d...@gmail.com wrote: On Sat, Dec 24, 2011 at 2:31 AM, Albert Y. C. Lai tre...@vex.net wrote: 1. a function f is strict if f ⊥ = ⊥ 2. ⊥ represents any computation which does not terminate, i.e. an exception or an infinite loop 3. strict describes the denotational semantics All three of these statements are true. The only potentially controversial one is 2, but any term that the operational semantics would identify as simple non-termination (which is invariably what they're talking about when they say 2; not some partially defined term) will be given denotation ⊥. B. Actually there are more, but apparently two is already enough to cause all kinds of incoherent statements. If I draw your attention to algebraic semantics, will you start saying it is too lazy, need to make it more idempotent? Yes, there are more than two. And they don't exist in completely separate vacuums from one another. Denotational and operational properties are sometimes (often?) correlated. And algebraic semantics is often the sweet spot for reasoning about the structure of the operational or denotational semantics of your code, without bringing in all the irrelevant details from the latter two. I can make a denotational semantics for System F where each term is denoted by its normal form (an operational concept). I think it's good to be clear on all these specifics, and people could do with a better recognition of the difference between (non-)strict and (lazy)eager (hint: you can have an eager, non-strict language). Can you elaborate? That's apparently my blind spot. But it isn't necessarily a problem that people speak in terms of more than one at once. The different kinds of semantics aren't in conflict with one another. The main problem would be that such casual mixing prevents newcomers from learning the distinctions by osmosis. -- Dan ___ 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] strict, lazy, non-strict, eager
Thanks, this makes sense. On Sun, Dec 25, 2011 at 10:03 AM, Dan Doel dan.d...@gmail.com wrote: On Sun, Dec 25, 2011 at 12:14 AM, Eugene Kirpichov ekirpic...@gmail.com wrote: On Sat, Dec 24, 2011 at 10:49 PM, Dan Doel dan.d...@gmail.com wrote: I think it's good to be clear on all these specifics, and people could do with a better recognition of the difference between (non-)strict and (lazy)eager (hint: you can have an eager, non-strict language). Can you elaborate? That's apparently my blind spot. A while back, there was a paper on something called (I believe) optimistic evaluation. The strategy goes like this: when you evaluate 'f x', first you start evaluating 'x'. If that takes too long, or you encounter an exception, you (re)thunk it, and continue evaluating the body of f lazy style, in case you don't really need x. This is arguably eager, since you reduce arguments to functions immediately if possible. And it has some advantages over lazy evaluation in common cases. For instance, it avoids foldl building up a huge nested thunk that would cause a stack overflow. But it isn't strict, because const 5 undefined is still 5. You can also imagine sparking on every function application, so that arguments automatically get reduced in parallel, and as soon as possible. I think that's been determined to not be very effective, though. -- Dan -- 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] book.realworldhaskell.org is down
Thanks. Now it's working - it wasn't at the moment of my email. On Sun, Dec 25, 2011 at 11:21 AM, Tom Murphy amin...@gmail.com wrote: realworldhaskell.org/book On Dec 25, 2011 1:46 AM, Eugene Kirpichov ekirpic...@gmail.com wrote: See subject. Is this expected? -- 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 -- 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
[Haskell-cafe] On stream processing, and a new release of timeplot coming
Hi Cafe,
In the last couple of days I completed my quest of making my graphing
utility timeplot ( http://jkff.info/software/timeplotters ) not load the
whole input dataset into memory and consequently be able to deal with
datasets of any size, provided however that the amount of data to *draw* is
not so large. On the go it also got a huge speedup - previously visualizing
a cluster activity dataset with a million events took around 15 minutes and
a gig of memory, now it takes 20 seconds and 6 Mb max residence.
(I haven't yet uploaded to hackage as I have to give it a bit more testing)
The refactoring involved a number of interesting programming patterns that
I'd like to share with you and ask for feedback - perhaps something can be
simplified.
The source is at http://github.com/jkff/timeplot
The datatype of incremental computations is at
https://github.com/jkff/timeplot/blob/master/Tools/TimePlot/Incremental.hs .
Strictness is extremely important here - the last memory leak I eliminated
was lack of bang patterns in teeSummary.
There's an interesting function statefulSummary that shows how closures
allow you to achieve encapsulation over an unknown piece of state -
curiously enough, you can't define StreamSummary a r as StreamSummary {
init :: s, insert :: a-s-s, finalize :: s-r } (existentially qualified
over s), as then you can't define summaryByKey - you don't know what type
to store in the states map.
It is used to incrementally build all plots simultaneously, shown by the
main loop in makeChart at
https://github.com/jkff/timeplot/blob/master/Tools/TimePlot.hs
Incremental building of plots of different types is at
https://github.com/jkff/timeplot/blob/master/Tools/TimePlot/Plots.hs
There are also a few interesting functions in that file - e.g.
edges2eventsSummary, which applies a summary over a stream of long events
to a stream of rise/fall edges.
This means that you can define a stream transformer (Stream a - Stream
b) as a function (StreamSummary b - StreamSummary a), which can be much
easier. I have to think more about this idea.
--
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Principal Engineer, Mirantis Inc. http://www.mirantis.com/
Editor, http://fprog.ru/
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[Haskell-cafe] Drawing charts over a lot of data
Hi cafe, Are there any (possibly unfinished?) libraries dedicated to drawing charts over large amounts of data? I mean, such amounts that you don't want to store the whole set of input data in memory and instead you prefer to do one or a few passes over the input, calling the library's drawing functions for each data point. I'm currently using the excellent Chart package http://hackage.haskell.org/package/Chart , but it seems to require quite a bit of work to become usable in this mode (I haven't looked really deep yet). So, I'd be happy if someone pointed me to an existing package (I didn't find one on hackage) or if someone expressed interest in making Chart avoid having the whole input in memory. -- 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] Ridiculously slow FFI, or cairo binding?
Hi Axel,
When do you expect to publish an updated version of gtk2hs on hackage?
On Thu, Nov 3, 2011 at 1:02 PM, Eugene Kirpichov ekirpic...@gmail.com wrote:
Hi,
The actual thanks for tracking this down go to Vincent Hanquez for finding
that we're doing a lot of gmp calls (and for making me aware of ltrace), and
to Felipe Lessa for finding that this is caused by poor code generated for
cFloatConv :)
Your changes look identical to those that I made in my copy.
On Thu, Nov 3, 2011 at 11:41 AM, Axel Simon axel.si...@in.tum.de wrote:
Hi Eugene,
On 02.11.2011, at 17:34, Eugene Kirpichov wrote:
Heh.
Guess what!
A simple {-# INLINE cFloatConv #-} helped to the same extent!
Axel, I think this change should be pretty easy to incorporate, and it
probably makes sense to inline all other functions in Types.chs too.
I've added INLINE pragmas to all these odd c2hs marshalling functions.
Could you pull and check if I've done it correctly?
Thanks for tracking this down!
Axel
Would you like me to send the trivial darcs patch or the gtk2hs team
will take care of this?
On Wed, Nov 2, 2011 at 7:29 PM, Felipe Almeida Lessa
felipe.le...@gmail.com wrote:
On Wed, Nov 2, 2011 at 11:24 AM, Jean-Marie Gaillourdet
j...@gaillourdet.net wrote:
Hi Eugene,
did you try using the SPECIALIZE pragma? It is part of the Haskell 98
and Haskell 2010 specifications.
I don't think it's going to make any difference, as the core already
have an specialized poor version. See my first e-mail.
--
Felipe.
--
Eugene Kirpichov
Principal Engineer, Mirantis Inc. http://www.mirantis.com/
Editor, http://fprog.ru/
--
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Principal Engineer, Mirantis Inc. http://www.mirantis.com/
Editor, http://fprog.ru/
--
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Principal Engineer, Mirantis Inc. http://www.mirantis.com/
Editor, http://fprog.ru/
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Re: [Haskell-cafe] Ridiculously slow FFI, or cairo binding?
Hi,
The actual thanks for tracking this down go to Vincent Hanquez for finding
that we're doing a lot of gmp calls (and for making me aware of ltrace),
and to Felipe Lessa for finding that this is caused by poor code generated
for cFloatConv :)
Your changes look identical to those that I made in my copy.
On Thu, Nov 3, 2011 at 11:41 AM, Axel Simon axel.si...@in.tum.de wrote:
Hi Eugene,
On 02.11.2011, at 17:34, Eugene Kirpichov wrote:
Heh.
Guess what!
A simple {-# INLINE cFloatConv #-} helped to the same extent!
Axel, I think this change should be pretty easy to incorporate, and it
probably makes sense to inline all other functions in Types.chs too.
I've added INLINE pragmas to all these odd c2hs marshalling functions.
Could you pull and check if I've done it correctly?
Thanks for tracking this down!
Axel
Would you like me to send the trivial darcs patch or the gtk2hs team
will take care of this?
On Wed, Nov 2, 2011 at 7:29 PM, Felipe Almeida Lessa
felipe.le...@gmail.com wrote:
On Wed, Nov 2, 2011 at 11:24 AM, Jean-Marie Gaillourdet
j...@gaillourdet.net wrote:
Hi Eugene,
did you try using the SPECIALIZE pragma? It is part of the Haskell 98
and Haskell 2010 specifications.
I don't think it's going to make any difference, as the core already
have an specialized poor version. See my first e-mail.
--
Felipe.
--
Eugene Kirpichov
Principal Engineer, Mirantis Inc. http://www.mirantis.com/
Editor, http://fprog.ru/
--
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Editor, http://fprog.ru/
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[Haskell-cafe] Ridiculously slow FFI, or cairo binding?
Hello,
I've got two very simple programs that draw a very simple picture using
cairo, doing a couple hundred thousand of cairo calls.
One program is in C++. The other is in Haskell and uses the cairo library
bindings.
The C++ program completes in a fraction of a second, the Haskell program
takes about 7-8 seconds to run. They produce exactly the same output.
What could be at fault here? Why are the cairo bindings working so slow? (I
suppose there isn't too much cairo-specific stuff here, perhaps it's a
general FFI question?)
#include cairo.h
int main() {
cairo_surface_t *surface =
cairo_image_surface_create(CAIRO_FORMAT_ARGB32, 1024, 768);
cairo_t *cr = cairo_create(surface);
cairo_set_source_rgb(cr, 0, 255, 0);
for(int x = 0; x 1024; x += 2) for(int y = 0; y 768; y += 2) {
cairo_rectangle(cr, x, y, 1, 1);
cairo_fill(cr);
}
cairo_surface_write_to_png(surface, picture.png);
return 0;
}
module Main where
import qualified Graphics.Rendering.Cairo as C
import Control.Monad
main = C.withImageSurface C.FormatARGB32 1024 768 $ \s - do
C.renderWith s $ do
C.setSourceRGBA 0 255 0 255
forM_ [0,2..1024] $ \x - do
forM_ [0,2..768] $ \y - do
C.rectangle x y 1 1
C.fill
C.surfaceWriteToPNG s picture.png
--
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Principal Engineer, Mirantis Inc. http://www.mirantis.com/
Editor, http://fprog.ru/
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Re: [Haskell-cafe] Ridiculously slow FFI, or cairo binding?
I forgot to specify my environment.
Windows Server 2008 R2 x64, ghc 7.0.3.
However, I observed the same speed differences on a 64-bit ubuntu with ghc
6.12 - I profiled my application with cairo-trace, and cairo-perf-trace
drew in a fraction of a second the picture that my Haskell program spend a
dozen seconds drawing.
On Wed, Nov 2, 2011 at 1:17 PM, Eugene Kirpichov ekirpic...@gmail.comwrote:
Hello,
I've got two very simple programs that draw a very simple picture using
cairo, doing a couple hundred thousand of cairo calls.
One program is in C++. The other is in Haskell and uses the cairo library
bindings.
The C++ program completes in a fraction of a second, the Haskell program
takes about 7-8 seconds to run. They produce exactly the same output.
What could be at fault here? Why are the cairo bindings working so slow?
(I suppose there isn't too much cairo-specific stuff here, perhaps it's a
general FFI question?)
#include cairo.h
int main() {
cairo_surface_t *surface =
cairo_image_surface_create(CAIRO_FORMAT_ARGB32, 1024, 768);
cairo_t *cr = cairo_create(surface);
cairo_set_source_rgb(cr, 0, 255, 0);
for(int x = 0; x 1024; x += 2) for(int y = 0; y 768; y += 2) {
cairo_rectangle(cr, x, y, 1, 1);
cairo_fill(cr);
}
cairo_surface_write_to_png(surface, picture.png);
return 0;
}
module Main where
import qualified Graphics.Rendering.Cairo as C
import Control.Monad
main = C.withImageSurface C.FormatARGB32 1024 768 $ \s - do
C.renderWith s $ do
C.setSourceRGBA 0 255 0 255
forM_ [0,2..1024] $ \x - do
forM_ [0,2..768] $ \y - do
C.rectangle x y 1 1
C.fill
C.surfaceWriteToPNG s picture.png
--
Eugene Kirpichov
Principal Engineer, Mirantis Inc. http://www.mirantis.com/
Editor, http://fprog.ru/
--
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Editor, http://fprog.ru/
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Re: [Haskell-cafe] Ridiculously slow FFI, or cairo binding?
Hi Claude, I suspected that the issue could be about unsafe foreign imports - all imports in the cairo bindings are safe. I compiled myself a version of cairo bindings with the rectangle and fill functions marked as unsafe. Unfortunately that didn't help the case at all, even though the core changed FFI calls from __pkg_ccall_GC to __pkg_ccall. The performance stayed the same; the overhead is elsewhere. On Wed, Nov 2, 2011 at 1:31 PM, Claude Heiland-Allen cla...@goto10.orgwrote: On 02/11/11 09:17, Eugene Kirpichov wrote: Hello, I've got two very simple programs that draw a very simple picture using cairo, doing a couple hundred thousand of cairo calls. One program is in C++. The other is in Haskell and uses the cairo library bindings. The C++ program completes in a fraction of a second, the Haskell program takes about 7-8 seconds to run. They produce exactly the same output. What could be at fault here? Why are the cairo bindings working so slow? (I suppose there isn't too much cairo-specific stuff here, perhaps it's a general FFI question?) I filed a bug report about this some months ago, having noticed similar slowness: gtk2hs ticket #1228 cairo performance is very bad http://hackage.haskell.org/**trac/gtk2hs/ticket/1228http://hackage.haskell.org/trac/gtk2hs/ticket/1228 My conclusion was that it isn't FFI being slow, but some other reason, possibly too much redirection / high level fanciness in the implementation of cairo bindings that the compiler can't see through to optimize aggressively, or possibly some Double / CDouble / realToFrac rubbishness. Claude __**_ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/**mailman/listinfo/haskell-cafehttp://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] Ridiculously slow FFI, or cairo binding?
Oh. This is pretty crazy, I wonder what they're doing with GMP so much...
I modified the Haskell program to use cairo directly, even with safe calls,
and it now takes the same time as the C program.
{-# LANGUAGE ForeignFunctionInterface #-}
module Main where
import qualified Graphics.Rendering.Cairo as C
import Control.Monad
import Foreign
import Foreign.C.Types
import Foreign.C.String
foreign import ccall cairo.h cairo_image_surface_create
cairo_image_surface_create :: CInt - CInt - CInt - IO (Ptr ())
foreign import ccall cairo.h cairo_create cairo_create :: Ptr () - IO
(Ptr ())
foreign import ccall cairo.h cairo_set_source_rgb cairo_set_source_rgb ::
Ptr () - CDouble - CDouble - CDouble - IO ()
foreign import ccall cairo.h cairo_rectangle cairo_rectangle :: Ptr () -
CDouble - CDouble - CDouble - CDouble - IO ()
foreign import ccall cairo.h cairo_fill cairo_fill :: Ptr () - IO ()
foreign import ccall cairo.h cairo_surface_write_to_png
cairo_surface_write_to_png :: Ptr () - CString - IO ()
main = do
s - cairo_image_surface_create 0 1024 768
cr - cairo_create s
cairo_set_source_rgb cr 0 255 0
forM_ [0,2..1024] $ \x - do
forM_ [0,2..768] $ \y - do
cairo_rectangle cr x y 1 1
cairo_fill cr
pic - newCString picture.png
cairo_surface_write_to_png s pic
On Wed, Nov 2, 2011 at 1:58 PM, Vincent Hanquez t...@snarc.org wrote:
On 11/02/2011 09:51 AM, Eugene Kirpichov wrote:
Hi Claude,
I suspected that the issue could be about unsafe foreign imports - all
imports in the cairo bindings are safe.
I compiled myself a version of cairo bindings with the rectangle and
fill functions marked as unsafe.
Unfortunately that didn't help the case at all, even though the core
changed FFI calls from __pkg_ccall_GC to __pkg_ccall. The performance
stayed the same; the overhead is elsewhere.
doing a ltrace, i think the reason is pretty obvious, there's a lot of
GMP calls:
__gmpz_init(0x7f5043171730, 1, 0x7f5043171750, 0x7f5043171740,
0x7f50431d2508) = 0x7f50431d2530
__gmpz_mul(0x7f5043171730, 0x7f5043171750, 0x7f5043171740, 0x7f50431d2538,
0x7f50431d2508) = 1
__gmpz_init(0x7f5043171728, 1, 0x7f5043171748, 0x7f5043171738,
0x7f50431d2538) = 0x7f50431d2568
__gmpz_mul(0x7f5043171728, 0x7f5043171748, 0x7f5043171738, 0x7f50431d2570,
0x7f50431d2538) = 1
__gmpn_gcd_1(0x7f50431d2580, 1, 1, 1, 1) = 1
repeated thousand of time
before each call cairo calls.
just to make sure, the C version doesn't exhibit this behavior.
--
Vincent
__**_
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Re: [Haskell-cafe] Ridiculously slow FFI, or cairo binding?
+gtk2hs-users
On Wed, Nov 2, 2011 at 2:10 PM, Eugene Kirpichov ekirpic...@gmail.comwrote:
Oh. This is pretty crazy, I wonder what they're doing with GMP so much...
I modified the Haskell program to use cairo directly, even with safe
calls, and it now takes the same time as the C program.
{-# LANGUAGE ForeignFunctionInterface #-}
module Main where
import qualified Graphics.Rendering.Cairo as C
import Control.Monad
import Foreign
import Foreign.C.Types
import Foreign.C.String
foreign import ccall cairo.h cairo_image_surface_create
cairo_image_surface_create :: CInt - CInt - CInt - IO (Ptr ())
foreign import ccall cairo.h cairo_create cairo_create :: Ptr () - IO
(Ptr ())
foreign import ccall cairo.h cairo_set_source_rgb cairo_set_source_rgb
:: Ptr () - CDouble - CDouble - CDouble - IO ()
foreign import ccall cairo.h cairo_rectangle cairo_rectangle :: Ptr ()
- CDouble - CDouble - CDouble - CDouble - IO ()
foreign import ccall cairo.h cairo_fill cairo_fill :: Ptr () - IO ()
foreign import ccall cairo.h cairo_surface_write_to_png
cairo_surface_write_to_png :: Ptr () - CString - IO ()
main = do
s - cairo_image_surface_create 0 1024 768
cr - cairo_create s
cairo_set_source_rgb cr 0 255 0
forM_ [0,2..1024] $ \x - do
forM_ [0,2..768] $ \y - do
cairo_rectangle cr x y 1 1
cairo_fill cr
pic - newCString picture.png
cairo_surface_write_to_png s pic
On Wed, Nov 2, 2011 at 1:58 PM, Vincent Hanquez t...@snarc.org wrote:
On 11/02/2011 09:51 AM, Eugene Kirpichov wrote:
Hi Claude,
I suspected that the issue could be about unsafe foreign imports - all
imports in the cairo bindings are safe.
I compiled myself a version of cairo bindings with the rectangle and
fill functions marked as unsafe.
Unfortunately that didn't help the case at all, even though the core
changed FFI calls from __pkg_ccall_GC to __pkg_ccall. The performance
stayed the same; the overhead is elsewhere.
doing a ltrace, i think the reason is pretty obvious, there's a lot of
GMP calls:
__gmpz_init(0x7f5043171730, 1, 0x7f5043171750, 0x7f5043171740,
0x7f50431d2508) = 0x7f50431d2530
__gmpz_mul(0x7f5043171730, 0x7f5043171750, 0x7f5043171740,
0x7f50431d2538, 0x7f50431d2508) = 1
__gmpz_init(0x7f5043171728, 1, 0x7f5043171748, 0x7f5043171738,
0x7f50431d2538) = 0x7f50431d2568
__gmpz_mul(0x7f5043171728, 0x7f5043171748, 0x7f5043171738,
0x7f50431d2570, 0x7f50431d2538) = 1
__gmpn_gcd_1(0x7f50431d2580, 1, 1, 1, 1) = 1
repeated thousand of time
before each call cairo calls.
just to make sure, the C version doesn't exhibit this behavior.
--
Vincent
__**_
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Editor, http://fprog.ru/
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Re: [Haskell-cafe] Ridiculously slow FFI, or cairo binding?
Any idea how to debug why all the GMP calls? I'm looking at even the auto-generated source for cairo bindings, but I don't see anything at all that could lead to *thousands* of them. On Wed, Nov 2, 2011 at 2:14 PM, Vincent Hanquez t...@snarc.org wrote: On 11/02/2011 10:10 AM, Eugene Kirpichov wrote: Oh. This is pretty crazy, I wonder what they're doing with GMP so much... I modified the Haskell program to use cairo directly, even with safe calls, and it now takes the same time as the C program. yep, i ended up doing the exact same thing for testing, foreign import ccall cairo_rectangle my_rectangle :: CI.Cairo - CDouble - CDouble - CDouble - CDouble - IO () and just replacing the rectangle call make almost all the difference for me (almost as fast as C) -- Vincent -- 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] Fwd: Ridiculously slow FFI, or cairo binding?
Yay!!!
I made a small change in Types.chs and got my original cairo-binding-based
program to be just as blazing fast. The only problem I have with this is
that I used multiparameter type classes.
Dear gtk2hs team! Is it possible to incorporate my changes? I'm pretty sure
people will be happy by an order-of-magnitude speedup. Probably the stuff
could be wrapped in #define's for those who aren't using GHC and can't use
multiparameter type classes?
I am pretty sure I could have done the same with rewrite rules, but I tried
for a while and to no avail.
FAILED SOLUTION: rewrite rules
cFloatConv :: (RealFloat a, RealFloat b) = a - b
cFloatConv = realToFrac
{-# NOINLINE cFloatConv #-}
{-# RULES cFloatConv/float2Double cFloatConv = float2Double #-}
{-# RULES cFloatConv/double2Float cFloatConv = double2Float #-}
{-# RULES cFloatConv/self cFloatConv = id #-}
For some reason, the rules don't fire. Anyone got an idea why?
SUCCEEDED SOLUTION: multiparameter type classes
I rewrote cFloatConv like this:
import GHC.Float
class (RealFloat a, RealFloat b) = CFloatConv a b where
cFloatConv :: a - b
cFloatConv = realToFrac
instance CFloatConv Double Double where cFloatConv = id
instance CFloatConv Double CDouble
instance CFloatConv CDouble Double
instance CFloatConv Float Float where cFloatConv = id
instance CFloatConv Float Double where cFloatConv = float2Double
instance CFloatConv Double Float where cFloatConv = double2Float
and replaced a couple of constraints in functions below by usage of
CFloatConv.
On Wed, Nov 2, 2011 at 2:25 PM, Felipe Almeida Lessa felipe.le...@gmail.com
wrote:
+gtk2hs-devel
On Wed, Nov 2, 2011 at 8:15 AM, Eugene Kirpichov ekirpic...@gmail.com
wrote:
Any idea how to debug why all the GMP calls?
I'm looking at even the auto-generated source for cairo bindings, but I
don't see anything at all that could lead to *thousands* of them.
Found them. Look at the Types module and you'll see
cFloatConv :: (RealFloat a, RealFloat b) = a - b
cFloatConv = realToFrac
This function (or its cousins peekFloatConv, withFloatConv...) are
used *everywhere*.
Looking at this module with ghc-core we see that GHC compiled a
generic version of cFloatConv:
Graphics.Rendering.Cairo.Types.$wcFloatConv
:: forall a_a3TN b_a3TO.
(RealFloat a_a3TN, RealFrac b_a3TO) =
a_a3TN - b_a3TO
[GblId,
Arity=3,
Unf=Unf{Src=vanilla, TopLvl=True, Arity=3, Value=True,
ConLike=True, Cheap=True, Expandable=True,
Guidance=IF_ARGS [3 3 0] 12 0}]
Graphics.Rendering.Cairo.Types.$wcFloatConv =
\ (@ a_a3TN)
(@ b_a3TO)
(w_s5zg :: RealFloat a_a3TN)
(ww_s5zj :: RealFrac b_a3TO)
(w1_s5zA :: a_a3TN) -
fromRational
@ b_a3TO
($p2RealFrac @ b_a3TO ww_s5zj)
(toRational
@ a_a3TN
($p1RealFrac
@ a_a3TN ($p1RealFloat @ a_a3TN w_s5zg))
w1_s5zA)
Note that this is basically cFloatConv = fromRational . toRational.
*However*, GHC also compiled a Double - Double specialization:
Graphics.Rendering.Cairo.Types.cFloatConv1
:: Double - Double
[GblId,
Arity=1,
Unf=Unf{Src=InlineStable, TopLvl=True, Arity=1, Value=True,
ConLike=True, Cheap=True, Expandable=True,
Guidance=ALWAYS_IF(unsat_ok=True,boring_ok=False)
Tmpl= \ (eta_B1 [Occ=Once!] :: Double) -
case eta_B1 of _ { D# ww_a5v3 [Occ=Once] -
case $w$ctoRational ww_a5v3
of _ { (# ww2_a5v8 [Occ=Once], ww3_a5v9 [Occ=Once] #) -
$wfromRat ww2_a5v8 ww3_a5v9
}
}}]
Graphics.Rendering.Cairo.Types.cFloatConv1 =
\ (eta_B1 :: Double) -
case eta_B1 of _ { D# ww_a5v3 -
case $w$ctoRational ww_a5v3
of _ { (# ww2_a5v8, ww3_a5v9 #) -
$wfromRat ww2_a5v8 ww3_a5v9
}
}
...which is also equivalent to fromRational . toRational however with
the type class inlined! Oh, god...
Cheers,
--
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Re: [Haskell-cafe] Fwd: Ridiculously slow FFI, or cairo binding?
Sorry for re-sending, my previous attempt got ignored by gtk2hs-devel
mailing list as I wasn't subscribed. Now I am.
On Wed, Nov 2, 2011 at 3:14 PM, Eugene Kirpichov ekirpic...@gmail.comwrote:
Yay!!!
I made a small change in Types.chs and got my original cairo-binding-based
program to be just as blazing fast. The only problem I have with this is
that I used multiparameter type classes.
Dear gtk2hs team! Is it possible to incorporate my changes? I'm pretty
sure people will be happy by an order-of-magnitude speedup. Probably the
stuff could be wrapped in #define's for those who aren't using GHC and
can't use multiparameter type classes?
I am pretty sure I could have done the same with rewrite rules, but I
tried for a while and to no avail.
FAILED SOLUTION: rewrite rules
cFloatConv :: (RealFloat a, RealFloat b) = a - b
cFloatConv = realToFrac
{-# NOINLINE cFloatConv #-}
{-# RULES cFloatConv/float2Double cFloatConv = float2Double #-}
{-# RULES cFloatConv/double2Float cFloatConv = double2Float #-}
{-# RULES cFloatConv/self cFloatConv = id #-}
For some reason, the rules don't fire. Anyone got an idea why?
SUCCEEDED SOLUTION: multiparameter type classes
I rewrote cFloatConv like this:
import GHC.Float
class (RealFloat a, RealFloat b) = CFloatConv a b where
cFloatConv :: a - b
cFloatConv = realToFrac
instance CFloatConv Double Double where cFloatConv = id
instance CFloatConv Double CDouble
instance CFloatConv CDouble Double
instance CFloatConv Float Float where cFloatConv = id
instance CFloatConv Float Double where cFloatConv = float2Double
instance CFloatConv Double Float where cFloatConv = double2Float
and replaced a couple of constraints in functions below by usage of
CFloatConv.
On Wed, Nov 2, 2011 at 2:25 PM, Felipe Almeida Lessa
felipe.le...@gmail.com wrote:
+gtk2hs-devel
On Wed, Nov 2, 2011 at 8:15 AM, Eugene Kirpichov ekirpic...@gmail.com
wrote:
Any idea how to debug why all the GMP calls?
I'm looking at even the auto-generated source for cairo bindings, but I
don't see anything at all that could lead to *thousands* of them.
Found them. Look at the Types module and you'll see
cFloatConv :: (RealFloat a, RealFloat b) = a - b
cFloatConv = realToFrac
This function (or its cousins peekFloatConv, withFloatConv...) are
used *everywhere*.
Looking at this module with ghc-core we see that GHC compiled a
generic version of cFloatConv:
Graphics.Rendering.Cairo.Types.$wcFloatConv
:: forall a_a3TN b_a3TO.
(RealFloat a_a3TN, RealFrac b_a3TO) =
a_a3TN - b_a3TO
[GblId,
Arity=3,
Unf=Unf{Src=vanilla, TopLvl=True, Arity=3, Value=True,
ConLike=True, Cheap=True, Expandable=True,
Guidance=IF_ARGS [3 3 0] 12 0}]
Graphics.Rendering.Cairo.Types.$wcFloatConv =
\ (@ a_a3TN)
(@ b_a3TO)
(w_s5zg :: RealFloat a_a3TN)
(ww_s5zj :: RealFrac b_a3TO)
(w1_s5zA :: a_a3TN) -
fromRational
@ b_a3TO
($p2RealFrac @ b_a3TO ww_s5zj)
(toRational
@ a_a3TN
($p1RealFrac
@ a_a3TN ($p1RealFloat @ a_a3TN w_s5zg))
w1_s5zA)
Note that this is basically cFloatConv = fromRational . toRational.
*However*, GHC also compiled a Double - Double specialization:
Graphics.Rendering.Cairo.Types.cFloatConv1
:: Double - Double
[GblId,
Arity=1,
Unf=Unf{Src=InlineStable, TopLvl=True, Arity=1, Value=True,
ConLike=True, Cheap=True, Expandable=True,
Guidance=ALWAYS_IF(unsat_ok=True,boring_ok=False)
Tmpl= \ (eta_B1 [Occ=Once!] :: Double) -
case eta_B1 of _ { D# ww_a5v3 [Occ=Once] -
case $w$ctoRational ww_a5v3
of _ { (# ww2_a5v8 [Occ=Once], ww3_a5v9 [Occ=Once] #) -
$wfromRat ww2_a5v8 ww3_a5v9
}
}}]
Graphics.Rendering.Cairo.Types.cFloatConv1 =
\ (eta_B1 :: Double) -
case eta_B1 of _ { D# ww_a5v3 -
case $w$ctoRational ww_a5v3
of _ { (# ww2_a5v8, ww3_a5v9 #) -
$wfromRat ww2_a5v8 ww3_a5v9
}
}
...which is also equivalent to fromRational . toRational however with
the type class inlined! Oh, god...
Cheers,
--
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Re: [Haskell-cafe] Ridiculously slow FFI, or cairo binding?
Hi,
No, I didn't, as I read in the GHC docs that it is deprecated in favor of
the RULES pragma (I wanted to replace specifically with floatToDouble and
doubleToFloat).
On Wed, Nov 2, 2011 at 5:24 PM, Jean-Marie Gaillourdet
j...@gaillourdet.netwrote:
Hi Eugene,
did you try using the SPECIALIZE pragma? It is part of the Haskell 98 and
Haskell 2010 specifications.
On 02.11.2011, at 12:14, Eugene Kirpichov wrote:
Yay!!!
I made a small change in Types.chs and got my original
cairo-binding-based program to be just as blazing fast. The only problem I
have with this is that I used multiparameter type classes.
Dear gtk2hs team! Is it possible to incorporate my changes? I'm pretty
sure people will be happy by an order-of-magnitude speedup. Probably the
stuff could be wrapped in #define's for those who aren't using GHC and
can't use multiparameter type classes?
I am pretty sure I could have done the same with rewrite rules, but I
tried for a while and to no avail.
FAILED SOLUTION: rewrite rules
cFloatConv :: (RealFloat a, RealFloat b) = a - b
cFloatConv = realToFrac
{-# NOINLINE cFloatConv #-}
{-# RULES cFloatConv/float2Double cFloatConv = float2Double #-}
{-# RULES cFloatConv/double2Float cFloatConv = double2Float #-}
{-# RULES cFloatConv/self cFloatConv = id #-}
See [1] in GHC User Guide.
cFloatConv :: (RealFloat a, RealFloat b) = a - b
cFloatConv = realToFrac -- or try fromRational . toRational
{-# SPECIALIZE cFloatConv :: Float - Double #-}
{-# SPECIALIZE cFloatConv :: Double - Float #-}
I did not try to compile or even benchmark this code. But I think it might
help in your case.
Cheers,
Jean
[1]:
http://www.haskell.org/ghc/docs/latest/html/users_guide/pragmas.html#specialize-pragma
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Re: [Haskell-cafe] Ridiculously slow FFI, or cairo binding?
Heh.
Guess what!
A simple {-# INLINE cFloatConv #-} helped to the same extent!
Axel, I think this change should be pretty easy to incorporate, and it
probably makes sense to inline all other functions in Types.chs too.
Would you like me to send the trivial darcs patch or the gtk2hs team
will take care of this?
On Wed, Nov 2, 2011 at 7:29 PM, Felipe Almeida Lessa
felipe.le...@gmail.com wrote:
On Wed, Nov 2, 2011 at 11:24 AM, Jean-Marie Gaillourdet
j...@gaillourdet.net wrote:
Hi Eugene,
did you try using the SPECIALIZE pragma? It is part of the Haskell 98 and
Haskell 2010 specifications.
I don't think it's going to make any difference, as the core already
have an specialized poor version. See my first e-mail.
--
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Re: [Haskell-cafe] Fwd: Ridiculously slow FFI, or cairo binding?
Thanks! I'll definitely consider your library in the future, but for now,
as we can see, there's no necessity in rewriting cFloatConv at all - {-#
INLINE #-} suffices :)
On Thu, Nov 3, 2011 at 3:30 AM, wren ng thornton w...@freegeek.org wrote:
On 11/2/11 7:14 AM, Eugene Kirpichov wrote:
I rewrote cFloatConv like this:
import GHC.Float
class (RealFloat a, RealFloat b) = CFloatConv a b where
cFloatConv :: a - b
cFloatConv = realToFrac
instance CFloatConv Double Double where cFloatConv = id
instance CFloatConv Double CDouble
instance CFloatConv CDouble Double
instance CFloatConv Float Float where cFloatConv = id
instance CFloatConv Float Double where cFloatConv = float2Double
instance CFloatConv Double Float where cFloatConv = double2Float
If you're going the MPTC route, I suggest you use
logfloat:Data.Number.**RealToFrac[1].
I don't have the CDouble and CFloat instances, but I could add them. The
instances themselves are only moderately more clever than yours ---namely
using CPP for portability to non-GHC compilers--- but I think it's good for
people to rally around one implementation of the solution instead of having
a bunch of copies of the same thing, each poorly maintained because of the
distributedness.
[1] http://hackage.haskell.org/**packages/archive/logfloat/0.**
12.1/doc/html/Data-Number-**RealToFrac.htmlhttp://hackage.haskell.org/packages/archive/logfloat/0.12.1/doc/html/Data-Number-RealToFrac.html
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Re: [Haskell-cafe] lazy A-star search
Anton, I think the mapM inside searchBy is incorrect. You're threading state between exploration of different branches, which you I think shouldn't be doing. 30.10.2011, в 19:44, Anton Kholomiov anton.kholom...@gmail.com написал(а): I'm misunderstanding astar. I've thought that 'whole route'-heuristic will prevent algorithm from going in circles. The more you circle around the more the whole route distance is. Thank you for showing this. Here is an updated version. searchBy function contains a state. State value accumulates visited nodes: -- | Heuristic search. Nodes are visited from smaller to greater. searchBy :: Ord b = (a - b) - (a - a - Ordering) - Tree a - [a] searchBy f heur t = evalState (searchBy' f heur t) S.empty searchBy' :: Ord b = (a - b) - (a - a - Ordering) - Tree a - State (S.Set b) [a] searchBy' f heur (Node v ts) = get = phi where phi visited | S.member (f v) visited = return [] | otherwise = put (S.insert (f v) visited) (v :) . foldr (mergeBy heur) [] $ mapM (searchBy' f heur) ts I need to add function Ord b = (a - b). It converts tree nodes into visited nodes. I'm using it for saving distance-values alongside with nodes in astar algorithm. In attachment you can find algorithm with your example. 2011/10/27 Ryan Ingram ryani.s...@gmail.com Also, this wasn't clear in my message, but the edges in the graph only go one way; towards the top/right; otherwise the best path is ABCDEHIJ :) On Thu, Oct 27, 2011 at 10:48 AM, Ryan Ingram ryani.s...@gmail.com wrote: You're missing one of the key insights from A-star (and simple djikstra, for that matter): once you visit a node, you don't have to visit it again. Consider a 5x2 2d graph with these edge costs: B 1 C 1 D 1 E 9 J 1 1 1 1 1 A 2 F 2 G 2 H 2 I with the start node being A, the target node being J, and the heuristic being manhattan distance. Your search will always try to take the top route, on every node along the bottom path, even though you visit every node along the top route in your first try at reaching the goal. You need a way to mark that a node is visited and remove it from future consideration, or else you're wasting work. A-star will visit the nodes in the order ABCDE FGHIJ; your algorithm visits the nodes in the order ABCDE FCDE GDE HE IJ. -- ryan On Sat, Oct 22, 2011 at 5:28 AM, Anton Kholomiov anton.kholom...@gmail.com wrote: Recently I was looking for an A-star search algorithm. I've found a package but I couldn't understand the code. Then I saw some blogposts but they were difficult to understand too. I thought about some easier solution that relies on laziness. And I've come to this: Heuristic search is like depth-first search but solutions in sub-trees are concatenated with mergeBy function, that concatenates two list by specific order: module Search where import Control.Applicative import Data.Function(on) import Control.Arrow(second) import Data.Tree -- | Heuristic search. Nodes are visited from smaller to greater. searchBy :: (a - a - Ordering) - Tree a - [a] searchBy heur (Node v ts) = v : foldr (mergeBy heur) [] (searchBy heur $ ts) -- | Merge two lists. Elements concatenated in specified order. mergeBy :: (a - a - Ordering) - [a] - [a] - [a] mergeBy _ a [] = a mergeBy _ []b = b mergeBy p (a:as)(b:bs) | a `p` b == LT= a : mergeBy p as (b:bs) | otherwise = b : mergeBy p bs (a:as) Now we can define specific heuristic search in terms of searchBy: -- | Heuristic is distance to goal. bestFirst :: Ord h = (a - h) - (a - [a]) - a - [a] bestFirst dist alts = searchBy (compare `on` dist) . unfoldTree (\a - (a, alts a)) -- | A-star search. -- Heuristic is estimated length of whole path. astar :: (Ord h, Num h) = (a - h) - (a - [(a, h)]) - a - [a] astar dist alts s0 = fmap fst $ searchBy (compare `on` astarDist) $ unfoldTree gen (s0, 0) where astarDist (a, d) = dist a + d gen (a, d) = d `seq` ((a, d), second (+d) $ alts a) I'm wondering is it effective enough? Anton ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe Search.hs ___ 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] When does the UNPACK pragma work?
Hi,
I'm trying to speed up Data.Time (the time package) 'cause my program is
spending a very substantial fraction of time manipulating dates.
I decided to start with strictifying and unpacking the date/time types, as
there's no point in having them be lazy and I indeed had a lot of allocation
in date/time arithmetic in my performance profile.
data UTCTime = UTCTime {
utctDay :: {-# UNPACK #-} !Day,
utctDayTime :: {-# UNPACK #-} !DiffTime
}
(unpacks and strictness mine)
newtype Day = ModifiedJulianDay {toModifiedJulianDay :: Integer}
newtype DiffTime = MkDiffTime Pico
And Pico is also essentially a newtype for Integer.
So, I'm getting warnings on this definition of UTCTime.
QUESTION: Is it the case that I can only UNPACK primitive fields, and not
even their newtypes?
Data\Time\Clock\UTC.hs:30:16:
Warning: Ignoring unusable UNPACK pragma on the
first argument of `UTCTime'
In the definition of data constructor `UTCTime'
In the data type declaration for `UTCTime'
Data\Time\Clock\UTC.hs:30:16:
Warning: Ignoring unusable UNPACK pragma on the
second argument of `UTCTime'
In the definition of data constructor `UTCTime'
In the data type declaration for `UTCTime'
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Re: [Haskell-cafe] When does the UNPACK pragma work?
Oh, I see, thanks!
So then, I guess, the solution would be to use a fixed-precision integer
type instead.
On Fri, Oct 28, 2011 at 1:54 PM, Daniel Fischer
daniel.is.fisc...@googlemail.com wrote:
On Friday 28 October 2011, 11:41:15, Eugene Kirpichov wrote:
newtype Day = ModifiedJulianDay {toModifiedJulianDay :: Integer}
newtype DiffTime = MkDiffTime Pico
And Pico is also essentially a newtype for Integer.
So, I'm getting warnings on this definition of UTCTime.
QUESTION: Is it the case that I can only UNPACK primitive fields, and
not even their newtypes?
The problem is that you can't {-# UNPACK #-} Integer.
You can only unpack single-constructor types.
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Re: [Haskell-cafe] When does the UNPACK pragma work?
Another question: Can I unpack some fields in a record and not unpack
others? Does their order matter then?
On Fri, Oct 28, 2011 at 1:57 PM, Eugene Kirpichov ekirpic...@gmail.comwrote:
Oh, I see, thanks!
So then, I guess, the solution would be to use a fixed-precision integer
type instead.
On Fri, Oct 28, 2011 at 1:54 PM, Daniel Fischer
daniel.is.fisc...@googlemail.com wrote:
On Friday 28 October 2011, 11:41:15, Eugene Kirpichov wrote:
newtype Day = ModifiedJulianDay {toModifiedJulianDay :: Integer}
newtype DiffTime = MkDiffTime Pico
And Pico is also essentially a newtype for Integer.
So, I'm getting warnings on this definition of UTCTime.
QUESTION: Is it the case that I can only UNPACK primitive fields, and
not even their newtypes?
The problem is that you can't {-# UNPACK #-} Integer.
You can only unpack single-constructor types.
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Re: [Haskell-cafe] When does the UNPACK pragma work?
On Fri, Oct 28, 2011 at 2:32 PM, Daniel Fischer daniel.is.fisc...@googlemail.com wrote: On Friday 28 October 2011, 11:57:54, Eugene Kirpichov wrote: Another question: Can I unpack some fields in a record and not unpack others? Yes, no problem with that. Does their order matter then? In what way? The order of the fields in the definition of the type will determine the order in which the components (pointers/unpacked values) appear in the constructor. That may influence performance, but I wouldn't expect a significant difference. Oh, OK. I was just thinking, maybe, you can only unpack a prefix of the field set... -- 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
[Haskell-cafe] Cross-compilation x64 - x86 easier under Ubuntu 11.10 with multiarch?
Hi cafe, Ubuntu 11.10 has been released, which includes support for multiarch https://wiki.ubuntu.com/MultiarchSpec Am I right that this will facilitate compiling Haskell code into x86 binaries on an x64 machine? -- 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
[Haskell-cafe] Packaged my log visualization tools
Hello cafe, I've packaged my log visualization tools in binary form for several platforms. Perhaps those of you who have better things to do than struggle installing them from source will find this useful :) Here you go: http://jkff.info/presentations/two-visualization-tools.pdf Documentation http://jkff.info/software/timeplotters-0.1-1_win32.zip Windows (any architecture) http://jkff.info/software/timeplotters-0.1-1_i386.deb Debian (i386) http://jkff.info/software/timeplotters-0.1-1_amd64.deb Debian (amd64) http://jkff.info/software/timeplotters-0.1-1_i386.tar.gz *nix binaries (i386), require gtk2.0, gmp3, libc6. http://jkff.info/software/timeplotters-0.1-1_amd64.tar.gz *nix binaries (amd64), require gtk2.0, gmp3, libc6. -- 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] regex-applicative library needs your help! (algorithmic challenge)
Hi, I don't see how fallback to NFA simulation is really a failure wrt DoS attacks. It's not exponential in time or memory, just linear memory (in size of regex) instead of constant, and slower than DFA. On Wed, Sep 14, 2011 at 1:29 AM, Roman Cheplyaka r...@ro-che.info wrote: * Chris Kuklewicz hask...@list.mightyreason.com [2011-09-13 08:21:55+0100] I wrote regex-tdfa, the efficient (though not yet lightning fast) Posix-like engine. You are not the first to want an efficient Perl-like engine. The answer you seek flows from Russ Cox (though in C++): http://google-opensource.blogspot.com/2010/03/re2-principled-approach-to-regular.html http://code.google.com/p/re2/ Quoting relevant bit: It also finds the leftmost-first match, the same match that Perl would, and can return submatch information. The one significant exception is that RE2 drops support for backreferences¹ and generalized zero-width assertions, because they cannot be implemented efficiently. Hi Chris, thanks for the response. There's one thing about Cox's work that I don't understand. On the page [1] he mentions that the algorithm falls back to direct NFA simulation (search for If all else fails on that page). This defeats his goal of defending against DoS attacks (the second paragraph of that page). And I wouldn't be comfortable with an algorithm that is worst-case exponential either. Then there's another issue: I specifically want a combinator library, and not every automaton-based algorithm can serve this purpose in a statically typed language (unless there's some clever trick I don't know). [1]: http://swtch.com/~rsc/regexp/regexp3.html -- Roman I. Cheplyaka :: http://ro-che.info/ ___ 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
[Haskell-cafe] alex 3.0 broken with Data.ByteString.Lazy - w2c conversion missing (fix attached)
Hi Simon,
I found a bug in alex-3.0 and I'm attaching a fixed source file -
templates/wrappers.hs (modified against alex-3.0 from cabal unpack).
Explanation:
I was installing bytestring-lexing 0.2.1 and it failed to install with
alex 3.0, which was released on Aug 4.
It succeeded, however, with the most recent earlier alex 2.3.5.
Turns out that the wrapper for lazy bytestrings (strict are ok) had
alexGetByte not doing w2c conversion:
alexGetByte (_, cs) | ByteString.null cs = Nothing
| otherwise = Just (ByteString.head cs,
(ByteString.head cs, ByteString.tail cs))
It should say ByteString.w2c $ ByteString.head cs here.
With this and an additional import of Data.ByteString.Internal (w2c),
the generated code compiles.
To reproduce, cabal unpack bytestring-lexing and try installing it.
Installation will fail, then manually alex the .x files in
Data/ByteString/Lex{,/Lazy} and try ghci'ing to them, doing the
modification I did and ghci'ing again.
--
Eugene Kirpichov
Principal Engineer, Mirantis Inc. http://www.mirantis.com/
Editor, http://fprog.ru/
wrappers.hs
Description: Binary data
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Re: [Haskell-cafe] Analyzing slow performance of a Haskell program
What about using unsafe array indexing operations? (i.e. array `unsafeAt` index)
2011/8/7 Chris Yuen kizzx2+hask...@gmail.com:
Here is an updated version using Data.Array.Unboxed http://ideone.com/YXuVL
And the profile http://hpaste.org/49940
Still taking 5+ minutes...
Chris
On Sun, Aug 7, 2011 at 5:20 PM, Daniel Fischer
daniel.is.fisc...@googlemail.com wrote:
On Sunday 07 August 2011, 10:52:20, Max Bolingbroke wrote:
In short I don't see how to get further without changing the algorithm
or doing some hacks like manual unrolling. Maybe someone else has some
ideas?
Well, the C# implementation uses arrays for lookup while the Haskell
version uses list lookups
in (tens !! fromIntegral t) ++ wordify x
and case'd functions
lenTens 0 = 0
lenTens 1 = 3
lenTens 2 = 6
lenTens 3 = 6
lenTens 4 = 5
lenTens 5 = 5
lenTens 6 = 5
lenTens 7 = 7
lenTens 8 = 6
lenTens 9 = 6
wordify is only called once at the end, so that should not have a
measurable impact, but the lenXXXs might.
I'm not sure what
CaseLen.$wlenTens :: GHC.Prim.Int# - GHC.Prim.Int#
[GblId,
Arity=1,
Str=DmdType L,
Unf=Unf{Src=vanilla, TopLvl=True, Arity=1, Value=True,
ConLike=True, Cheap=True, Expandable=True,
Guidance=IF_ARGS [12] 11 0}]
CaseLen.$wlenTens =
\ (ww_shY :: GHC.Prim.Int#) -
case ww_shY of _ {
__DEFAULT -
CaseLen.lenTens1
`cast` (CoUnsafe GHC.Types.Int GHC.Prim.Int#
:: GHC.Types.Int ~ GHC.Prim.Int#);
0 - 0;
1 - 3;
2 - 6;
3 - 6;
4 - 5;
5 - 5;
6 - 5;
7 - 7;
8 - 6;
9 - 6
}
means at a lower level, but it's certainly worth trying out whether an
unboxed array lookup is faster.
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Principal Engineer, Mirantis Inc. http://www.mirantis.com/
Editor, http://fprog.ru/
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Re: [Haskell-cafe] Haskell fgl example
I've got a small example here https://github.com/jkff/minxmod/blob/master/Buchi.hs . 2011/7/19 Rohit Agrawalla rohit.agrawa...@gmail.com: I am new to haskell and the haskell fgl (functional graph library). l am looking for some examples of the haskell fgl. Would appreciate any pointers regarding the same. -- Rohit ___ 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] pointer equality
reallyUnsafePointerEq#, and it really is as unsafe as it sounds :) 20.07.2011, в 7:51, Nikhil A. Patil patil.nik...@gmail.com написал(а): Hi, Is there any way of getting the following code to immediately return True without performing the element-by-element comparison? Essentially this boils down to checking whether pointers are equal before comparing the contents. main = print $ f == f where f = [1..10^9] Thanks!! nikhil ___ 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
Re: [Haskell-cafe] Patterns for processing large but finite streams
Plain old lazy lists do not allow me to combine multiple concurrent computations, e.g. I cannot define average from sum and length. 2011/7/1 Heinrich Apfelmus apfel...@quantentunnel.de: Eugene Kirpichov wrote: I'm rewriting timeplot to avoid holding the whole input in memory, and naturally a problem arises: How to represent large but finite streams and functions that process them, returning other streams or some kinds of aggregate values? Examples: * Adjacent differences of a stream of numbers * Given a stream of numbers with times, split it into buckets by time of given width and produce a stream of (bucket, 50%,75% and 90% quantiles in this bucket) * Sum a stream of numbers Is this, perhaps, what comonads are for? Or iteratees? Plain old lazy lists? Best regards, Heinrich Apfelmus -- http://apfelmus.nfshost.com ___ 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] Patterns for processing large but finite streams
I meant the average of the whole list - given a sumS and lengthS (S for Stream), write meanS as something like liftS2 (/) sumS lengthS. Or is that possible with lazy lists too? (looks like arrows actually - which arrow is appropriate here?) 2011/7/1 Malcolm Wallace malcolm.wall...@me.com: Sure you can. runningAverage :: Int - [Double] - [Double] runningAverage n xs = let chunk = take n xs in (sum chunk / length chunk) : runningAverage (tail xs) Lazy lists are absolutely ideal for this purpose. Regards, Malcolm On 1 Jul 2011, at 07:33, Eugene Kirpichov wrote: Plain old lazy lists do not allow me to combine multiple concurrent computations, e.g. I cannot define average from sum and length. 2011/7/1 Heinrich Apfelmus apfel...@quantentunnel.de: Eugene Kirpichov wrote: I'm rewriting timeplot to avoid holding the whole input in memory, and naturally a problem arises: How to represent large but finite streams and functions that process them, returning other streams or some kinds of aggregate values? Examples: * Adjacent differences of a stream of numbers * Given a stream of numbers with times, split it into buckets by time of given width and produce a stream of (bucket, 50%,75% and 90% quantiles in this bucket) * Sum a stream of numbers Is this, perhaps, what comonads are for? Or iteratees? Plain old lazy lists? Best regards, Heinrich Apfelmus -- http://apfelmus.nfshost.com ___ 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 -- 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] Patterns for processing large but finite streams
Alexey, your definition of mean does not look like liftS2 (/) sum length - you have to manually fuse these computations. I'm asking for a formalism that does this fusion automatically (and guaranteedly). 2011/7/1 Alexey Khudyakov alexey.sklad...@gmail.com: On Fri, Jul 1, 2011 at 12:21 PM, Eugene Kirpichov ekirpic...@gmail.com wrote: I meant the average of the whole list - given a sumS and lengthS (S for Stream), write meanS as something like liftS2 (/) sumS lengthS. Or is that possible with lazy lists too? Sure you can. Sum, length and mean could be calculated as left fold. If you need to calculate more that one statistic at time you can combine accumulators sum = foldl (+) 0 length = foldl (\n _ - n+1) 0 data Mean Double Int mean = foldl (\(Mean m n) x - Mean (m + (x - m) / fromIntegral (n+1)) (n+1)) (Mean 0 0) AFAIU iteratees basically use same technique. -- 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] Patterns for processing large but finite streams
Thanks but I'm afraid that's still not quite what I'm looking for; guess I'll have to define my desire by my implementation - so once it's ready I'll show the result to cafe :) 2011/7/1 Alexey Khudyakov alexey.sklad...@gmail.com: On Fri, Jul 1, 2011 at 12:54 PM, Eugene Kirpichov ekirpic...@gmail.com wrote: Alexey, your definition of mean does not look like liftS2 (/) sum length - you have to manually fuse these computations. Well it was fused for numerical stability I'm asking for a formalism that does this fusion automatically (and guaranteedly). Joining accumulators is quite straightforward. So is joining of initial state. Just creating a joinAcc :: (acc1 - x - acc1) - (acc2 - x - acc2) - (acc1,acc2) - x - (acc1,acc2) joinAcc f1 f2 (s1,s2) x = (f1 s1 x, f2 s2 x) Still you have to handle them separately. sum' = foldl (+) 0 len = foldl (\n _ - n+1) 0 sumLen = foldl (joinAcc (+) (\n _ - n+1)) (0,0) There is more regular approach but it only works with statistics. (function which do not depend on order of elements in the sample) For every statistics monoid for its evaluation could be constructed. For example sum: newtype Sum a = Sum a instance Num a = Monoid (Sum a) where mempty = Sum 0 mappend (Sum a) (Sum b) = Sum (a+b) Composition of these monoids becomes trivial. Just use I pursued this approach in monoid-statistics[1] package. It's reasonably well documented [1] http://hackage.haskell.org/package/monoid-statistics -- 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] Patterns for processing large but finite streams
Hi, You're right, reifying stream processing functions seems indeed the way to go - and that looks even more like arrows :) I thought of something like this: data SP i o = Yield [o] (Maybe (Maybe i - SP i o)) Scalar functions like sum and length are just SP's that return a single item in the output stream. sum :: (Num a) = SP a a sum = sum' 0 where sum' s = Yield [] $ Just $ maybe (Yield [s] Nothing) (sum' . (s+)) Adjacent differences would be like liftA2 (-) input laggedInput laggedInput would be like: laggedInput :: SP i i laggedInput = li Nothing where li maybePrev = Yield (maybe2list maybePrev) $ Just $ maybe empty (li . Just) Looks like this can be made into an instance of Arrow and can be composed etc. 2011/7/1 Heinrich Apfelmus apfel...@quantentunnel.de: Eugene Kirpichov wrote: Plain old lazy lists do not allow me to combine multiple concurrent computations, e.g. I cannot define average from sum and length. I meant the average of the whole list - given a sumS and lengthS (S for Stream), write meanS as something like liftS2 (/) sumS lengthS. Or is that possible with lazy lists too? (looks like arrows actually - which arrow is appropriate here?) That's a very good point. Just to clarify for everyone: Eugene wants to write the function average almost *literally* as average xs = sum xs / length xs but he wants the functions sum and length to fuse, so that the input stream xs is *not* shared as a whole. I have thought about this problem for a while actually and have observed the following: 1) You are not looking for a representation of streams, but for a representation of *functions* on streams. The essence of a function on streams is its case analysis of the input. Hence, the simplest solution is to make the case analysis explicit: data StringTo a = CaseOf a (Char - StringTo a) -- function on a stream (here: String) interpret :: StringTo a - (String - a) interpret (CaseOf nil cons) [] = nil interpret (CaseOf nil cons) (x:xs) = interpret (cons x) xs instance Applicative StringTo where pure a = CaseOf a (const $ pure a) (CaseOf nil1 cons1) * (CaseOf nil2 cons2) = CaseOf (nil1 $ nil2) (\c - cons1 c * cons2 c) length = go 0 where go n = CaseOf n (\_ - go $! n+1) average = liftA2 (/) sum length In other words, if you reify case .. of expression , you will be able to fuse them. 2) If Haskell were to support some kind of evaluation under the lambda (partial evaluation, head normal form instead of weak head normal form), it would be unnecessary to make the case expressions implicit. Rather, the applicative instance could be written as follows instance Applicative ((-) String) where pure a = const a f * x = \cs - case cs of [] - f [] $ x [] (c:cs) - let f' cs = f (c:cs) -- partial evaluation on this x' cs = x (c:cs) in f' `partialseq` x' `partialseq` (f' * x') cs We could simply write average = liftA2 (/) sum length and everything would magically fuse. 3) John Hughes has already thought about this problem in his PhD thesis. :) (but it is not available for download on the internet, unfortunately. :( ). His solution was a SYNCHLIST primitive in conjunction with some sort of parallelism PAR. Basically, the SYNCHLIST primitive only allows simultaneous access to the input stream and the parallelism is used to make that simultaneity happen. Best regards, Heinrich Apfelmus -- http://apfelmus.nfshost.com ___ 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
[Haskell-cafe] Patterns for processing large but finite streams
Hi, I'm rewriting timeplot to avoid holding the whole input in memory, and naturally a problem arises: How to represent large but finite streams and functions that process them, returning other streams or some kinds of aggregate values? Examples: * Adjacent differences of a stream of numbers * Given a stream of numbers with times, split it into buckets by time of given width and produce a stream of (bucket, 50%,75% and 90% quantiles in this bucket) * Sum a stream of numbers Is this, perhaps, what comonads are for? Or iteratees? -- 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] Conditional IO ?
| otherwise = return () or: handleParseErrors errors = when (not . null $ errors) $ writeFile . 2011/6/20 Dmitri O.Kondratiev doko...@gmail.com: Hi, What is right way to do conditional IO? For example, I need to write to file errors only in case they exist, otherwise my function should do nothing: handleParseErrors errors | (not . null) errors = writeFile parse-errors.txt (show errors) | otherwise = ? What should be an 'otherwise' case ? Thanks! ___ 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] Installing Gtk2Hs on Win32
Hi, http://www.gtk.org/download/win32.php http://www.gtk.org/download/win64.php search for all-in one bundle. 2011/6/10 Dmitri O.Kondratiev doko...@gmail.com: Please help to find pre-compiled binary libraries of Gtk+ for Win32. Gtk2Hs insatll instructions at: http://code.haskell.org/gtk2hs/INSTALL tells us: [quote] Building on Windows Installation on Windows is nearly as easy as on Unix platforms. However, you need to download the pre-compiled binary libraries of Gtk+ and all it's dependent libraries. Point your browser to http://www.gtk.org/download-windows.html and download one of the All-in-one bundles. Note that you do *not* need to install MinGW nor MSys (but it does not hurt if they are installed on your system). Install the binaries by unpacking them into a directory without spaces. [/quote] This link (http://www.gtk.org/download-windows.html) is dead. Where to get pre-compiled binary libraries of Gtk+ ? Thanks! ___ 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] Errors installing 'Haskell Charts'
Hi, You forgot to install gtk2hs-buildtools, it includes pkg-config. 2011/6/10 Dmitri O.Kondratiev doko...@gmail.com: I am trying to install HaskellCharts at: http://dockerz.net/twd/HaskellCharts Running: cabal update cabal install gtk2hs-buildtools cabal install gtk cabal install chart goes well untill 'cabal install chart' which results in: C:\wks\RCAcabal install chart Resolving dependencies... C:\Users\DKONDR~1\AppData\Local\Temp\cairo-0.12.03136\cairo-0.12.0\Gtk2HsSetup.h s:25:2: warning: #warning Setup.hs is guessing the version of Cabal. If compilat ion of Setup.hs fails use -DCABAL_VERSION_MINOR=x for Cabal version 1.x.0 when b uilding (prefixed by --ghc-option= when using the 'cabal' command) [1 of 2] Compiling Gtk2HsSetup ( C:\Users\DKONDR~1\AppData\Local\Temp\cairo -0.12.03136\cairo-0.12.0\Gtk2HsSetup.hs, C:\Users\DKONDR~1\AppData\Local\Temp\ca iro-0.12.03136\cairo-0.12.0\dist\setup\Gtk2HsSetup.o ) [2 of 2] Compiling Main ( C:\Users\DKONDR~1\AppData\Local\Temp\cairo -0.12.03136\cairo-0.12.0\Setup.hs, C:\Users\DKONDR~1\AppData\Local\Temp\cairo-0. 12.03136\cairo-0.12.0\dist\setup\Main.o ) Linking C:\Users\DKONDR~1\AppData\Local\Temp\cairo-0.12.03136\cairo-0.12.0\dist\ setup\setup.exe ... Configuring cairo-0.12.0... setup.exe: The program pkg-config version =0.9.0 is required but it could not be found. C:\Users\DKONDR~1\AppData\Local\Temp\glib-0.12.03136\glib-0.12.0\Gtk2HsSetup.hs: 25:2: warning: #warning Setup.hs is guessing the version of Cabal. If compilatio n of Setup.hs fails use -DCABAL_VERSION_MINOR=x for Cabal version 1.x.0 when bui lding (prefixed by --ghc-option= when using the 'cabal' command) [1 of 2] Compiling Gtk2HsSetup ( C:\Users\DKONDR~1\AppData\Local\Temp\glib- 0.12.03136\glib-0.12.0\Gtk2HsSetup.hs, C:\Users\DKONDR~1\AppData\Local\Temp\glib -0.12.03136\glib-0.12.0\dist\setup\Gtk2HsSetup.o ) [2 of 2] Compiling Main ( C:\Users\DKONDR~1\AppData\Local\Temp\glib- 0.12.03136\glib-0.12.0\Setup.hs, C:\Users\DKONDR~1\AppData\Local\Temp\glib-0.12. 03136\glib-0.12.0\dist\setup\Main.o ) Linking C:\Users\DKONDR~1\AppData\Local\Temp\glib-0.12.03136\glib-0.12.0\dist\se tup\setup.exe ... Configuring glib-0.12.0... setup.exe: The program pkg-config version =0.9.0 is required but it could not be found. cabal: Error: some packages failed to install: Chart-0.14 depends on glib-0.12.0 which failed to install. cairo-0.12.0 failed during the configure step. The exception was: ExitFailure 1 gio-0.12.0 depends on glib-0.12.0 which failed to install. glib-0.12.0 failed during the configure step. The exception was: ExitFailure 1 gtk-0.12.0 depends on glib-0.12.0 which failed to install. pango-0.12.0 depends on glib-0.12.0 which failed to install. Where to get glib-0.12.0 ? Thanks! ___ 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] *GROUP HUG*
Why so? I think it wouldn't. data FList a = FNil | FCons Int a (FList a) empty = FNil len FNil = 0 len (FCons n _) = n cons x xs = FCons (1 + len xs) x xs tail (FCons _ _ xs) = xs 2011/5/24 Tony Morris tonymor...@gmail.com: On 24/05/11 22:41, Johannes Waldmann wrote: Then tell me, why does calculating the length of a (Haskell) list has O(n) complexity. Infiniticity aside, tail would become O(n) if you store a length with each cons cell. -- Tony Morris http://tmorris.net/ ___ 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] Markov chain algorithm (from The Practice of Programming, Kernighan/Pike)
Because insertWith has a different type than your code needs. It's not like a - b - b, it's a - a - a and (:) is not like this. Try insertWith (++ or flip (++)) [(Moby, Dick)] 2011/5/11 michael rice nowg...@yahoo.com It's hard to improve on a 20 line Awk program for generating text but I thought it would be fun to investigate a Haskell solution. Why can't I cons an element onto an existing list? Michael Prelude Data.List Data.Map insertWith (:) (Moby, Dick) will (fromList [((Joe, Blow),[is]), ((Moby, Dick),[may])]) interactive:1:11: Occurs check: cannot construct the infinite type: a = [a] Expected type: a Inferred type: [a] In the first argument of `insertWith', namely `(:)' In the expression: insertWith (:) (Moby, Dick) will (fromList [((Joe, Blow), [is]), ((Moby, Dick), [may])]) Prelude Data.List Data.Map ___ 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
[Haskell-cafe] Cairo package broken on Windows, or am I cooking it wrong?
Hello, After a moderate struggle with getting gtk2hs to install on Windows, I tried to install Chart and got a linker message saying _cairo_image_surface_get_data was missing. After another struggle I figured that if I launch ghci -lcairo-2 then everything works fine. I tried patching cairo.cabal by adding this line: extra-libraries: cairo-2 and reinstalling cairo. This helped, I could install Chart without problems. My question is: Should this line be added to cairo.cabal, or should everything have worked fine in some other magical way, but did not, because of some other error? How can I diagnose what's wrong? How is cabal install generally supposed to find that a dll is needed, if I don't write it down in the extra-libraries field? -- 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] For Project Euler #1 isn't it more efficient to generate just the numbers you need? Spoiler
One doesn't have to touch them to compute their sum. 2011/5/7 KC kc1...@gmail.com: Do you mean O(1) complexity? Don't you have to touch at least the multiples of 3 5 making it O(k) where is the number of multiples of 3 and the number of multiples of 5? On Fri, May 6, 2011 at 10:10 PM, Lyndon Maydwell maydw...@gmail.com wrote: If you're looking for efficiency, I believe you can actually do #1 in constant time: On Sat, May 7, 2011 at 7:31 AM, cas...@istar.ca wrote: -- Instead of this -- sumMultiples3or5 s = sum [x | x - [3..s-1], x `mod` 3 == 0 || x `mod` 5 == 0] -- Isn't this faster sumMultiples3or5 s = sum ([x | x - [3,6..s-1]] `merge` [x | x - [5,10..s-1]]) merge xs [] = xs merge [] ys = ys merge txs@(x:xs) tys@(y:ys) | x y = x : xs `merge` tys | x y = y : txs `merge` ys | otherwise = x : xs `merge` ys ___ 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 -- -- Regards, KC ___ 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] ANNOUNCE: iterIO-0.1 - iteratee-based IO with pipe operators
Sounds just terrific! Thanks! 06.05.2011, в 8:15, David Mazieres dm-list-haskell-c...@scs.stanford.edu написал(а): Hi, everyone. I'm pleased to announce the release of a new iteratee implementation, iterIO: http://hackage.haskell.org/package/iterIO IterIO is an attempt to make iteratees easier to use through an interface based on pipeline stages reminiscent of Unix command pipelines. Particularly if you've looked at iteratees before and been intimidated, please have a look at iterIO to see if it makes them more accessible. Some aspects of iterIO that should simplify learning and using iteratees are: * Every aspect of the library is thoroughly document in haddock including numerous examples of use. * Enumerators are easy to build out of iteratees. * There is no difference between enumerators and enumeratees (i.e., inner pipeline stages). The former is just a type-restricted version of the latter. * Parsing combinators provide detailed error reporting and support LL(*) rather than LL(1) parsing, leading to fewer non-intuitive parsing failures. A couple of tricks avoid consuming excessive memory for backtracking. * Super-fast LL(1) parsing is also available through seamless integration with attoparsec. * A universal exception mechanism works across invocations of mtl monad transformers, thereby unifying error handling. * All pipe operators have uniform semantics, eliminating corner cases. In particular, if the writing end of a pipe fails, the reading end always gets EOF, allowing it to clean up resources. * One can catch exceptions thrown by any contiguous subset of stages in a pipeline. Moreover, enumerator exception handlers can resume downstream stages that haven't failed. * The package is full of useful iteratees and enumerators, including basic file and socket processing, parsec-like combinators, string search, zlib/gzip compression, SSL, HTTP, and loopback enumerator/iteratee pairs for testing a protocol implementation against itself. Please enjoy. I'd love to hear feedback. David ___ 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
Re: [Haskell-cafe] ANN: timeplot-0.3.0 - the analyst's swiss army knife for visualizing ad-hoc log files
Hello, Sorry for the broken link: the correct link to the presentation is: http://jkff.info/presentations/two-visualization-tools.pdf 2011/4/30 Eugene Kirpichov ekirpic...@gmail.com: Hello fellow haskellers, I announce the release of timeplot-0.3.0, the analyst's swiss army knife for visualizing ad-hoc log files. Links: * http://jkff.info/presentation/two-visualization-tools - a presentation saying what the tools are all about and giving plenty of graphical examples on cluster computing use cases. At the end of the presentation there's also a couple of slides about installation. It is a little bit outdated, it corresponds to versions just before 0.3.0. * http://hackage.haskell.org/package/timeplot * http://github.com/jkff/timeplot * The sibling tool, splot - for visualizing the activity of many concurrent processes - http://hackage.haskell.org/package/splot and http://github.com/jkff/splot . It has also gotten a couple of new features since my last announcement. The major new feature of tplot is the introduction of subplots, the 'within' plots. It allows one to plot data from several sub-tracks on one track of the graph: - several line- or dot-plots - several plots of sums or cumulative sums, perhaps stacked (to see how the sub-tracks contribute to the total sum - e.g. if your log speaks about different types of overhead and you wish to see how they contribute to the total) - stacked activity count plot - a generalization of the previous activity count plot, which allows you to, given a log saying like Machine started servicing job JOB1 ... Machine finished servicing job JOB1 etc, plot how many machines are servicing each job at any moment, in a stacked fashion - so, how loads by different jobs contribute to the whole cluster's load. The activity frequency plot plots the same on a relative scale. The syntax is, for example: within[.] dots or within[.] acount or even within[.] duration cumsum stacked etc. Note that these are of course just example use cases and the tool is universal, it is not in any sense specialized to clusters, jobs, overheads or actually even to logs. I'd like to encourage you to give it a try and look around for a use case :) If you do give the tool a try, please tell me if something goes wrong, be it an installation problem or a bug (the version is fresh released, so this is quite possible). -- Eugene Kirpichov Principal Engineer, Mirantis Inc. http://www.mirantis.com/ Editor, http://fprog.ru/ -- 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
[Haskell-cafe] ANN: timeplot-0.3.0 - the analyst's swiss army knife for visualizing ad-hoc log files
Hello fellow haskellers, I announce the release of timeplot-0.3.0, the analyst's swiss army knife for visualizing ad-hoc log files. Links: * http://jkff.info/presentation/two-visualization-tools - a presentation saying what the tools are all about and giving plenty of graphical examples on cluster computing use cases. At the end of the presentation there's also a couple of slides about installation. It is a little bit outdated, it corresponds to versions just before 0.3.0. * http://hackage.haskell.org/package/timeplot * http://github.com/jkff/timeplot * The sibling tool, splot - for visualizing the activity of many concurrent processes - http://hackage.haskell.org/package/splot and http://github.com/jkff/splot . It has also gotten a couple of new features since my last announcement. The major new feature of tplot is the introduction of subplots, the 'within' plots. It allows one to plot data from several sub-tracks on one track of the graph: - several line- or dot-plots - several plots of sums or cumulative sums, perhaps stacked (to see how the sub-tracks contribute to the total sum - e.g. if your log speaks about different types of overhead and you wish to see how they contribute to the total) - stacked activity count plot - a generalization of the previous activity count plot, which allows you to, given a log saying like Machine started servicing job JOB1 ... Machine finished servicing job JOB1 etc, plot how many machines are servicing each job at any moment, in a stacked fashion - so, how loads by different jobs contribute to the whole cluster's load. The activity frequency plot plots the same on a relative scale. The syntax is, for example: within[.] dots or within[.] acount or even within[.] duration cumsum stacked etc. Note that these are of course just example use cases and the tool is universal, it is not in any sense specialized to clusters, jobs, overheads or actually even to logs. I'd like to encourage you to give it a try and look around for a use case :) If you do give the tool a try, please tell me if something goes wrong, be it an installation problem or a bug (the version is fresh released, so this is quite possible). -- 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] tplot and splot - analyst's swiss army knifes for visualizing log files
Hello Ferenc,
Thank you for reporting the bug - it's very curious, I will look into
it in the nearest couple of days.
Could you please send me privately the actual input file on which the
program crashes?
I have added a downloadable link to the presentation to all places
where the slideshare link was present (finally making some use of my
hosting...).
Here it is: http://jkff.info/presentations/two-visualization-tools.pdf
2011/3/17 Ferenc Wagner wf...@niif.hu:
Eugene Kirpichov ekirpic...@gmail.com writes:
2010/12/17 Henning Thielemann schlepp...@henning-thielemann.de:
Eugene Kirpichov schrieb:
I've published a large presentation about two Haskell-based tools of
mine - tplot and splot.
Their motto is visualize system behavior from logs with a shell
one-liner.
Based on my experience, they usually seem to live up to this motto.
http://www.slideshare.net/jkff/two-visualization-tools
[attention attractor: the presentation has *really a lot* of pictures]
... and complete TeX code attached! :-) However can I also view a simple
PDF document of the presentation?
You can download the PDF here -
http://www.slideshare.net/jkff/two-visualization-tools/download
(however one has to be logged in to Slideshare, for example with a
facebook acct., for this link to work)
Just in case, I'm also attaching a PDF of the current version to this
email, but visiting the link is preferable, since I'll be updating the
contents.
Please, if at all possible, link an up-to-date downloadable PDF from the
documentation (http://hackage.haskell.org/package/timeplot) or from the
homepage (http://haskell.org/haskellwiki/Timeplot) to make our life
easier!
Anyway, your tools look very interesting, I gave tplot a shot.
Unfortunately, I hit various strange failures:
$ head -4 or.log
Mar 8 18:55:11 =overrun 1
Mar 8 18:55:13 =overrun 6
Mar 8 18:55:15 =overrun 13
Mar 8 18:55:16 =overrun 3
$ wc -l or.log
466 or.log
$ ls -l or.log overruns466.log
lrwxrwxrwx 1 wferi wferi 15 Mar 17 14:45 or.log - overruns466.log
-rw-rw-r-- 1 wferi wferi 12587 Mar 17 14:35 overruns466.log
$ tplot -if or.log -tf 'date %b %e %T' -o overruns.png -k 'overrun' 'sum 10'
This worked just fine. However, when given the same file with a longer
name, tplot does not terminate:
$ tplot -if overruns466.log -tf 'date %b %e %T' -o overruns.png -k 'overrun'
'sum 10'
^C
while doing the same the other way around still works:
$ cat overruns466.log | tplot -if - -tf 'date %b %e %T' -o overruns.png -k
'overrun' 'sum 10'
Choosing any other extension (svg, pdf or ps) also results in
nontermination (or at least unbearable runtime and memory consumption).
Adding a simple no-op statement, like:
diff -ur ../timeplot-0.2.19/Tools/TimePlot.hs ./Tools/TimePlot.hs
--- ../timeplot-0.2.19/Tools/TimePlot.hs 2011-03-09 11:36:24.0
+0100
+++ ./Tools/TimePlot.hs 2011-03-17 16:42:57.247625607 +0100
@@ -627,6 +627,7 @@
when (null args || args == [--help]) $ showHelp exitSuccess
case (readConf args) of
Conf conf - do
+ putStr
let render = case (outFormat conf) of {
PNG - \c w h f - const () `fmap` renderableToPNGFile c w h f;
PDF - renderableToPDFFile ;
also results in nontermination, even in the previously working case.
Something is clearly wrong here, seemingly in the runtime IO system.
--
Thanks,
Feri.
GHC 6.12.1
Chart-0.14
bytestring-0.9.1.5
bytestring-lexing-0.2.1
cairo-0.11.0
colour-2.3.1
containers-0.3.0.0
data-accessor-0.2.1.3
data-accessor-template-0.2.1.7
haskell98-1.0.1.1
regex-tdfa-1.1.4
strptime-1.0.1
time-1.1.4
--
Eugene Kirpichov
Principal Engineer,
Mirantis Inc. http://www.mirantis.com/
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Re: [Haskell-cafe] Haskell IDE
A year and something ago I used Leksah and I was reasonably satisfied with what it had to offer at that time. If I'm understanding correctly, it has been much improved since. However, now I actually use vim - but that's because I'm scared of trying to install Leksah on Windows (maybe it isn't hard, I haven't tried) and because I'm only doing rather tiny things with Haskell at the moment. 2011/3/3 Hauschild, Klaus (EXT) klaus.hauschild@siemens.com: Hi Haskellers, whats your Haskell IDE of choise? Currently I use leksah. Is the EclipseFP Plugin for Eclipse a real alternative? Thanks Klaus ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Eugene Kirpichov Senior Software Engineer, Mirantis Inc. http://www.mirantis.com/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Haskell platform installation failure on OS X 10.6.6 (intel)
Hello, Below is an experience report from Artem (cc'd) on a failed installation of Haskell platform on a Mac. OS: OS X 10.6.6 CPU: Intel Core i5 Platform downloaded from: http://lambda.haskell.org/hp-tmp/2010.2.0.0/haskell-platform-2010.2.0.0.i386.dmg Sequence of actions: Downloaded the file, mounted the image, ran Install new GHC, pressed OK until the following screen appeared http://i.imgur.com/GGdbg.png - there the Install button was disabled; pressing change install location did not help since only 1 option was available there, and it was already selected. After that, Artem tried to uninstall GHC, but unsuccessfully, since OS told that it was not installed. Then he tried to install the platform, and eventually got the following error around moving files into place: http://i.imgur.com/YHb22.png I've also heard somewhat similar problem reports on installing haskell-platform on OS X from other people (I myself don't have it) - like being unable to install it without first installing XCode, etc. Can anyone help resolve this issue? I'm sure this is not expected behavior. What further information would help find the cause? -- Eugene Kirpichov Senior Software Engineer, Mirantis Inc. http://www.mirantis.com/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell platform installation failure on OS X 10.6.6 (intel)
Thanks Gregory, Indeed xcode was not installed - however I wonder, why is it a dependency? It seems quite a heavyweight thing to require for installing Haskell, and this requirement may very well be a good reason to *not* install it... Could you please point me to the ticket you opened? I was not able to google it. 2011/2/24 Gregory Collins g...@gregorycollins.net: Hello, Usually this is because XCode is not installed. I believe the README states that this is a dependency for the install process. I opened a ticket with GHC HQ a while ago re: making this scenario friendlier for users. G. On Thu, Feb 24, 2011 at 3:41 PM, Eugene Kirpichov ekirpic...@gmail.com wrote: Hello, Below is an experience report from Artem (cc'd) on a failed installation of Haskell platform on a Mac. OS: OS X 10.6.6 CPU: Intel Core i5 Platform downloaded from: http://lambda.haskell.org/hp-tmp/2010.2.0.0/haskell-platform-2010.2.0.0.i386.dmg Sequence of actions: Downloaded the file, mounted the image, ran Install new GHC, pressed OK until the following screen appeared http://i.imgur.com/GGdbg.png - there the Install button was disabled; pressing change install location did not help since only 1 option was available there, and it was already selected. After that, Artem tried to uninstall GHC, but unsuccessfully, since OS told that it was not installed. Then he tried to install the platform, and eventually got the following error around moving files into place: http://i.imgur.com/YHb22.png I've also heard somewhat similar problem reports on installing haskell-platform on OS X from other people (I myself don't have it) - like being unable to install it without first installing XCode, etc. Can anyone help resolve this issue? I'm sure this is not expected behavior. What further information would help find the cause? -- Eugene Kirpichov Senior Software Engineer, Mirantis Inc. http://www.mirantis.com/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Gregory Collins g...@gregorycollins.net -- Eugene Kirpichov Senior Software Engineer, Mirantis Inc. http://www.mirantis.com/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
