February 2007 - Haskell

Profiling Feedback to Optimize Memoization Caching
by Tom Hawkins 23 Feb '07

23 Feb '07

After programming in Haskell for about a year now, I have found it allows we to quickly develop initial programs; thanks to the expressiveness of the language and type system. But due to performance concerns, I typically have to restructure the initial program, guided by profiling, to reduce time or memory consumption. Many times, this refactoring process helps illuminate a better strategic approach to the program. But very often, only a few inefficient functions need to be equipped with memoization. I can certainly speed up these functions with explicit memoization, usually by threading a Map or Set through the recursive decent. But doing so always degrades the legibility of the original function. Are there any tools to automate this process, so as not to clutter the code with "Have-I-been-here-before?" tests and supporting data structures? To what extent do Haskell compilers use memoization? Is there any way to guide automatic memoization? Also, do any compilers use profiling data to enable or re-adjust memoization caches of the worst offenders? In ECAD, we would call this an in-place optimization (IPO). -Tom

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Re: [Haskell] GHC/ Fortress -Parallel Computing
by Jan-Willem Maessen 23 Feb '07

23 Feb '07

On Feb 23, 2007, at 5:33 AM, Stefan Aeschbacher wrote: > Hi > > 2007/2/23, Jan-Willem Maessen <Janwillem.Maessen(a)sun.com>: >> > ... >> >> You'd be better off asking on one of the Fortress mailing lists (see >> http://fortress.sunsource.net/; I suggest joining the discuss mailing >> list and asking there). Sadly, I'm in a little to deep to really do >> the topic justice myself. I know there are community members there >> who are working on tutorial documents. > > Are these mailinglists active? At least as active as, say, the Haskell mailing list in its first five years or so! In all seriousness, there's one open-source prototype language implementation, which has been available for all of six weeks or so. The lists have only been up for about four weeks. If you post there, I guarantee there will be a minimum of six times as many well- informed Fortress implementors on the mailing list as you'll find here. -Jan-Willem Maessen Project Fortress > Judging from the archives there is not > much happening there. I already thought that joining one of these > lists would be good to see what is happening with fortress but when I > saw the content of the archives I did not subscribe and forgot about > it (until this thread came up). > > regards > > Stefan

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ETAPS 2007: Call for Participation
by João Saraiva 23 Feb '07

23 Feb '07

***************************************************************** *** *** *** ETAPS 2007 *** *** March 24 - April 1, 2007 *** *** Braga, Portugal *** *** *** *** http://www.di.uminho.pt/etaps07/ *** *** *** *** CALL FOR PARTICIPATION *** *** *** *** Normal Registration Deadline: 26th February, 2007 *** *** Students Grant Deadline : 26th February, 2007 *** *** *** ***************************************************************** The European Joint Conferences on Theory and Practice of Software (ETAPS) is the primary European forum for academic and industrial researchers working on topics related to Software Science. It is a confederation of five main conferences, several satellite workshops and other events. ETAPS 2007 is taking place in Braga, Portugal. Braga, capital of the Minho province, is an ancient city in the heart of the green and fertile region known as the Costa Verde. The region is known for its attractiveness in terms of climate, gastronomy, prices, and culture. Braga is known for its barroque churches and splendid 18th century houses. The old city is solemn and antique, but animated with commercial activity and academic life. ============================================================================ 5 Conferences- 18 Satellite Workshops- 3 Tutorials- Tool Demonstrations ============================================================================ ------------------------------------------------------------------------- Main Conferences ------------------------------------------------------------------------- CC 2007: International Conference on Compiler Construction http://cc2007.cs.brown.edu/ ESOP 2007: European Symposium on Programming http://rap.dsi.unifi.it/esop07/ FASE 2007: Fundamental Approaches to Software Engineering http://fase07.di.fc.ul.pt FOSSACS 2007: Foundations of Software Science and Computation Structures http://www2.in.tum.de/~seidl/fossacs07/ TACAS 2007: Tools and Algorithms for the Construction and Analysis of Systems http://www.doc.ic.ac.uk/tacas07/ ----------------------------------------------------------------------- Invited Speakers ----------------------------------------------------------------------- ETAPS 2007: Rance Cleaveland - University of Maryland, USA ETAPS 2007: Bertrand Meyer - ETH Zürich, Switzerland CC 2007: Don Batory - University of Texas at Austin, USA ESOP 2007: Andrew Pitts - Cambridge University, UK FASE 2007: Jan Bosch - Nokia, Finland FOSSACS 2007: Radha Jagadeesan - DePaul University, USA TACAS 2007: K. Rustan M. Leino - Microsoft Research, USA Further invited speakers are giving talks in the satellite workshops. ----------------------------------------------------------------------- Satellite Workshops ----------------------------------------------------------------------- ACCAT: Applied and Computational Category Theory http://tfs.cs.tu-berlin.de/workshops/accat2007/ AVIS: Int. Workshop on Automated Verification of Infinite-State Systems http://chacs.nrl.navy.mil/AVIS07 Bytecode: Bytecode Semantics, Verification, Analysis and Transformation http://www.sci.univr.it/~spoto/Bytecode07/ COCV: Sixth Workshop on Compiler Optimization Meets Compiler Verification http://pes.cs.tu-berlin.de/cocv2007/ FESCA: Formal Foundations of Embedded Software and Component-Based Software Architectures http://palab.dcs.kcl.ac.uk/fesca/ FinCo: Foundations of Interactive Computation http://www.cs.brown.edu/sites/finco07/ GT-VMT: Int. Workshop on Graph Transformation and Visual Modeling Techniques http://www.cs.le.ac.uk/events/GTVMT07/ HAV: Heap Analysis and Verification http://www.cs.tau.ac.il/~msagiv/hav.html HFL: Hardware design using Functional Languages http://hfl07.hflworkshop.org/ LDTA: Seventh Workshop on Language Descriptions, Tools and Applications http://www.di.uminho.pt/ldta07 MBT: Third Workshop on Model Based Testing http://react.cs.uni-sb.de/mbt2007/ MOMPES: Model-based Methodologies for Pervasive and Embedded Software http://www.di.uminho.pt/mompes OpenCert: Foundations and Techniques for Open Source Software Certification http://opencert.iist.unu.edu/ QAPL: Fifth Workshop on Quantitative Aspects of Programming Languages http://www.cse.yorku.ca/qapl07 SC: Software Composition http://ssel.vub.ac.be/sc2007 SLA++P: Model-driven High-level Programming of Embedded Systems http://web.uni-bamberg.de/wiai/gdi/SLAP07/ TERMGRAPH: Fourth International Workshop on Computing with Terms and Graphs http://www.termgraph.org.uk WITS: Seventh Workshop on Issues in the Theory of Security http://www.dsi.unive.it/IFIPWG1_7/wits2007.html ----------------------------------------------------------------------- Tutorials ----------------------------------------------------------------------- Program Transformation with Stratego/XT Martin Bravenboer (Utrecht University) and Eelco Visser (Delft University of Technology) Beyond the Generators: Practical Techniques for Real-World Software Generation Anthony M. Sloane (Macquarie University) Mobility, Ubiquity, and Security Gilles Barthe (INRIA), David Pichardie (IRISA), David Aspinall (Univ. of Edinburgh), Peter Müller (ETH Zurich), Lennart Beringer (LMU Munich) and Joe Kiniry (UC Dublin) ----------------------------------------------------------------------- Tool Demonstrations ----------------------------------------------------------------------- Demonstrations of tools presenting advances on the state of the art have been selected and are integrated in the programmes of the main conferences. ----------------------------------------------------------------------- Registration and Contact Details ----------------------------------------------------------------------- For online registration, please visit http://www.di.uminho.pt/etaps07/ and go to menu item "Registration". Contact details are available at the menu item "Contact us". In case of any questions not addressed on the web pages, please email etaps07(a)di.uminho.pt.

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Re: [Haskell] GHC/ Fortress -Parallel Computing
by goenzoy＠web.de 23 Feb '07

23 Feb '07

Hallo Jan-Willem, Hallo all, Thanks for the clarification first. And coming to your statement > We've certainly looked to the FP community for inspiration in many aspects of the language > is there anything planned to advice programmers what use Haskell, to code in Fortress. The document what I have in mind in this direction is a Introduction in Lisp for Python programmer. http://norvig.com/python-lisp.html Any feedback welcome Regards Gottfried www.wirtschaftswunder.co.uk www.5152.eu > -----Ursprüngliche Nachricht----- > Von: Jan-Willem Maessen <Janwillem.Maessen(a)sun.com> > Gesendet: 20.02.07 15:58:14 > An: "Gottfried F. Zojer" <goenzoy(a)web.de> > CC: haskell(a)haskell.org > Betreff: Re: [Haskell] GHC/ Fortress -Parallel Computing > > On Feb 19, 2007, at 4:17 PM, Gottfried F. Zojer wrote: > > > Hallo to all, > > > > > > Just curious after reading a posting on the internet. > > Is somebody using Fortress in combination with Haskell ( GHC) in a > > parallel setup. > > http://en.wikipedia.org/wiki/Fortress_programming_language > > Not to my knowledge. The Fortress implementation is still at the > prototype stage; the prototype runs on the JVM, and JVM/Haskell > interoperability is known to be a bit tricky. In general there are > substantial challenges to integrating two languages with independent > garbage-collected run time systems. Add in independent notions of > transactional memory, rather different thread scheduling models, and > so forth and the problem becomes trickier still. > > That said, there is certainly at least one Haskell programmer writing > Fortress code (I wrote much of the library and some of the code > examples in the language implementation). We've certainly looked to > the FP community for inspiration in many aspects of the language. My > favorite example: Fortress generators are essentially build forms for > algebras in the Boom hierarchy, and we're effectively doing library- > driven foldr/build elimination (except in this algebra it's map- > reduce/build instead). > > -Jan-Willem Maessen > Project Fortress > Sun Microsystems > > > http://research.sun.com/projects/plrg/faq/index.html > > http://fortress.sunsource.net/ > > > > > > Thanks for any feedback > > > > > > Regards > > > > Gottfried > > > > www.wirtschaftswunder.co.uk > > > > www.5152.eu > > _______________________________________________ > > Haskell mailing list > > Haskell(a)haskell.org > > http://www.haskell.org/mailman/listinfo/haskell > >

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research position at Nokia Research Center Cambridge US
by jamey.hicks＠nokia.com 22 Feb '07

22 Feb '07

Position available: Senior Research Engineer We seek an exceptional, highly motivated individual who is interested in a unique opportunity to collaborate with a world-class academic research community. This position is for the Armo project at NRC Cambridge (http://research.nokia.com/locations/cambridge/) using Bluespec hardware description language (http://www.bluespec.com/) to radically improve Nokia's ability to develop advanced SOCs and corresponding software for future mobile phones and mobile computers. We are investigating co-development of hardware and software components for such devices. Success in the project will lead to both academic publication as well as a significant positive impact on Nokia products and engineering. The ideal candidate will have an advanced degree and several years of industrial research experience. In addition to being expert in one or more technical areas, a successful candidate must be able to quickly master new fields of study and new technology. Candidates should be strong individual contributors with broad Computer Science engineering background and skills. They must be self-directed and require a minimum amount of supervision. As an individual contributor the candidate must be able and willing to work independently as well as participate as a member of other projects. In addition, candidates must have strong communication skills. They must be able to lead technology transfer activities, write research papers and proposals, participate in industrial standards activities (this may include international travel), and manage internal and external business relationships. Needed Competencies and Skills Expertise in computer architecture, parallel programming is required. Expertise in hardware definition languages such as Verilog, VHDL, and Bluespec is desired. Expertise in several programming languages and environments such as Haskell, Lisp, Java, C, C++, Symbian, Unix or Linux is needed. In depth understanding of operating systems, distributed systems and network protocols is desired. Department/Team Description Nokia Research Center Cambridge is a one year old group of 16 researchers located in Cambridge, Massachusetts. NRCC's charter is to renew Nokia via open innovation, in particular via joint research projects with MIT Computer Science and Artificial Intelligence Laboratory. We are a systems research center, investigating all aspects of future mobile phones and services. Our goal is to develop new technologies, applications, and services, and to work with the rest of Nokia to make these a reality. Contact: Jamey Hicks, Director, Nokia Research Center Cambridge jamey.hicks(a)nokia.com <mailto:jamey.hicks@nokia.com> http://research.nokia.com/locations/cambridge/ 3 Cambridge Center Cambridge MA 02142 US

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New PhD Positions Computing Science, Chalmers University
by Koen Claessen 22 Feb '07

22 Feb '07

(apologies for multiple copies -- please forward to all interested parties) New PhD Positions 2007 Division of Computing Science, Chalmers University of Technology http://chalmersnyheter.chalmers.se/chalmers03/english/eng_vacanciesarticle.… The Division has about 80 researchers, half being faculty members and half PhD students. Our focus is on algorithms, bioinformatics, distributed systems and computing, functional programming, formal methods, interaction design, language technology, language based security, parallel and high performance computing, programming logic and type theory, but research is not restricted to these topics. For more information, see http://www.chalmers.se/cse/EN/research/research-groups Knowledge of Swedish is not a prerequisite for application. English is our working language for research. Both Swedish and English are used in undergraduate courses. Half of our researchers and PhD students are native Swedes; the rest come from more than 20 different countries. Applicants must have a very good undergraduate degree in Computing Science or in a related subject with a strong Computing Science component. They must also have a strong, documented interest in doing research. You may even apply if you have not yet completed your degree, but expect to do so by 1 September 2007. We particularly encourage applicants with interests in: - applying techniques from functional programming to develop novel methods of hardware design and verification. For more information on this point contact Mary Sheeran (ms(at)cs.chalmers.se); - automated theorem proving, SAT-solving, and functional programming. For more information on this point see http://www.cs.chalmers.se/~koen/folkung/, or contact Koen Claessen (koen(at)chalmers.se); - distributed algorithms for providing coordination services to networked or multiprocessor applications. For more information on this point see the webapages of the group Distributed Computing and Systems http://www.cs.chalmers.se/~dcs/ or contact Marina Papatriantafilou (ptrianta(at)cs.chalmers.se); - program analysis for software engineering. For more information on this point see the webpage of the group Software Methodologies and Systems (http://sms.cs.chalmers.se, "Open Positions") or contact Sibylle Schupp (<lastname>@cs.chalmers.se). The department especially welcomes female applicants. How to apply ------------ The full application should contain 1. A letter of application, listing specific research interests 2. A curriculum vitae 3. Attested copies of degrees and other certificates 4. Copies of relevant work, for example dissertations or articles, that you have authored or co-authored 5. Letters of recommendation from your teachers or employers *** You MUST include or e-mail Letters of Recommendation: we typically get over 100 apps, and it is simply not feasible for us to request individual letters *** The job reference number is: 2007/30. The last date for your full application to arrive is March 9, 2007 Send your application electronically in PDF files or by paper-mail to Registrator, Chalmers University of Technology, Se-412 96 Göteborg, Sweden. Phone: +4631 772 1000, Fax: +4631 772 4922, E-mail: registrator(at)adm.chalmers.se If you need more information regarding PhD studies at the division please contact Philippas Tsigas (tsigas(at)cs.chalmers.se). You will know the result of your application by 30 May 2007. Union representatives: SACO Jan Lindér, TCO Monica Orrbacke, SEKO Ralf Berndtsson

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TFP 2007: Registration and Progam
by TFP 2007 22 Feb '07

22 Feb '07

Dear Colleagues, You may now resgister for TFP 2007! TFP 2007 will be held April 2-4, 2007 in New York City, USA. Our invited speaker is John McCarthy, Stanford University. Further details can be found at our homepage: http://cs.shu.edu/tfp2007/ . You may register at: http://cs.shu.edu/tfp2007/registration.html . The registration deadline is March 2, 2007 (11:59 p.m. EST). Accomodations information may be found at: http://cs.shu.edu/tfp2007/accomodations.html . We kindly remind you that the deadline to make a hotel reservation at the guaranteed rates offered to TFP 2007 participants is also quickly approaching. We are proud to announce our program of accepted talks: Unifying Hybrid Types and Contracts Jessica Gronski and Cormac Flanagan A Dual Semantics for the Data Description Calculus Yitzhak Mandelbaum, Kathleen Fisher, and David Walker A Metalanguage for Structural Operational Semantics Matthew Lakin and Andrew Pitts An Arrow Based Semantics for Interactive Applications Peter Achten, Marko van Eekelen, Maarten de Mol, and Rinus Plasmeijer Dependent Types: Easy as Pie Dimitrios Vytiniotis and Stephanie Weirich Constructing Correct Circuits -- Hardware Modelling with Dependent Types Edwin Brady, James McKinna, and Kevin Hammond Why Would Extensible Dependent Types Matter Pablo Nogueira and Bruno Oliveira Bytecode Verification for Haskell Robert Dockins and Samuel Z. Guyer UnreadTVar: Extending Haskell Software Transactional Memory for Performance Nehir Sonmez, Cristian Perfumo, Srdjan Stipic, Adrian Cristal, Osman S. Unsal, and Mateo Valero A New Functional Implementation of Grover's Fast Search Algorithm Justin Stallard and Murray Gross An Inference Algorithm for Guaranteeing Safe Destruction Manuel Montenegro, Ricardo Peña, and Clara Segura Hierarchical Master/Worker Skeletons Jost Berthold, Mischa Dieterle, Rita Loogen, and Steffen Priebe Property Directed Generation of First-Order Test Data Fredrik Lindblad Refactoring for Comprehension Gustavo Villavicencio Towards a Box Calculus for Hume Gudmund Grov and Greg Michaelson Scaled Regression: A Refinement of Primitive Recursion Daniel Leivant Equality-Based Uniqueness Typing Edsko de Vries, Rinus Plasmeijer, and David Abrahamson Lightweight Static Resources: Sexy Types for Embedded and Systems Programming Oleg Kiselyov and Chung-chieh Shan Space-Efficient Gradual Typing David Herman, Aaron Tomb, and Cormac Flanagan Use-Based Reference of Polymorphism Dave King and John Hannan Designing a Generic Graph Library Using ML Functors Sylvain Conchon, Jean-Christophe Filliatre, and Julien Signoles The SCIence Joint Research Activity Kevin Hammond, Dana Petcu, Phil Trinder, Abdallah Al Zain, Steve Linton, and Greg Michaelson Generic and Index Programming Jeremy Gibbons, Meng Wang, and Bruno C d. S. Oliveira The AHA Project Marko van Eekelen, Olha Shkaravska, Ron van Kesteren, Bart Jacobs, Sjaak Smetsers, and Erik Poll Studying Helium Program Bahaviour with the Neon Library Jurriaan Hage and Peter van Keeken Design and Implementation of JFP Hao Xu Hop Client-Side Compilation Florian Loitsch Adaptive High-Level Scheduling in a Generic Parallel Runtime Environment Jost Berthold, Abyd Al-Zain, and Hans-Wolfgang Loidl Bundles Pack Tighter than Lists Francisco Lopez-Fraguas, Juan Rodriguez-Hortala, and Jaime Sanchez-Hernandez Model-Based Testing of Thin-Client Web Applications and Navigation Input Pieter Koopman, Peter Achten, and Rinus Plasmeijer We look forward to seeing you at TFP 2007! Cheers, Marco ************************************************************************************ Dr. Marco T. Morazan TFP 2007 Program Committee Chair http://cs.shu.edu/tfp2007/

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Composing applicative functors?
by Conal Elliott 22 Feb '07

22 Feb '07

Is the composition instance of Control.Applicative defined somewhere? I see it in the McBride & Paterson paper [1], but not in the library docs [2]. I'd rather pull it in from a library than (re)define it myself. [1] http://www.soi.city.ac.uk/~ross/papers/Applicative.pdf [2] http://www.haskell.org/ghc/docs/latest/html/libraries/base/Control-Applicat…

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Data.Hashtable operations in IO?
by ROBERT DOUGLAS HOELZ 20 Feb '07

20 Feb '07

I was reading the docs for Data.Hashtable, and quickly noticed that operations on a hashtable are of the IO monad. Why is this? I should think that the operations would look like this: insert :: Hashtable -> key -> val -> Hashtable lookup :: Hashtable -> key -> a etc. Thanks, Rob Hoelz

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GHC/ Fortress -Parallel Computing
by Gottfried F. Zojer 20 Feb '07

20 Feb '07

Hallo to all, Just curious after reading a posting on the internet. Is somebody using Fortress in combination with Haskell ( GHC) in a parallel setup. http://en.wikipedia.org/wiki/Fortress_programming_language >From Sun Microsystems : http://research.sun.com/projects/plrg/faq/index.html http://fortress.sunsource.net/ Thanks for any feedback Regards Gottfried www.wirtschaftswunder.co.uk www.5152.eu

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