April 2016 - Haskell-Cafe

CFP: Functional High Performance Computing 2016
by David Duke 03 Apr '16

03 Apr '16

====================================================================== CALL FOR PAPERS FHPC 2016 The 5th ACM SIGPLAN Workshop on Functional High-Performance Computing Nara, Japan September 22, 2016 https://sites.google.com/site/fhpcworkshops/ Co-located with the International Conference on Functional Programming (ICFP 2016) Submission Deadline: Friday, 10 June, 2016 (anywhere on earth) ====================================================================== The FHPC workshop aims at bringing together researchers exploring uses of functional (or more generally, declarative or high-level) programming technology in application domains where high performance is essential. The aim of the meeting is to enable sharing of results, experiences, and novel ideas about how high-level, declarative specifications of computationally challenging problems can serve as maintainable and portable code that approaches (or even exceeds) the performance of machine-oriented imperative implementations. All aspects of performance critical programming and parallel programming are in-scope for the workshop, irrespective of hardware target. This includes both traditional large-scale scientific computing (HPC), as well as work targeting single node systems with SMPs, GPUs, FPGAs, or embedded processors. It is becoming apparent that radically new and well founded methodologies for programming such systems are required to address their inherent complexity and to reconcile execution performance with programming productivity. Experience reports are also welcome. Proceedings: ============ FHPC 2016 seeks to encourage a range of submissions, focussing on work in progress and facilitating early exchange of ideas and open discussion on innovative and/or emerging results. To this end submissions should take the form of short (maximum 6 page) papers. Accepted papers will be published by the ACM and will appear in the ACM Digital Library. * Submissions due: Friday, 10 June, 2016 (anywhere on earth) * Author notification: Friday, 8 July, 2016 * Final copy due: Sunday, 31 July, 2016 Submitted papers must be in portable document format (PDF), formatted according to the ACM SIGPLAN style guidelines (2 column, 9pt format). See http://www.sigplan.org/authorInformation.htm for more information and style files. Papers should be no longer than 6 pages. Contributions to FHPC 2016 should be submitted via Easychair, at the following URL: * https://www.easychair.org/conferences/?conf=fhpc16 The FHPC workshops adhere to the ACM SIGPLAN policies regarding programme committee contributions and republication. Any paper submitted must adhere to ACM SIGPLAN's republication policy. PC member submissions are welcome, but will be reviewed to a higher standard. http://www.sigplan.org/Resources/Policies/Review http://www.sigplan.org/Resources/Policies/Republication Travel Support: =============== Student attendees with accepted papers can apply for a SIGPLAN PAC grant to help cover travel expenses. PAC also offers other support, such as for child-care expenses during the meeting or for travel costs for companions of SIGPLAN members with physical disabilities, as well as for travel from locations outside of North America and Europe. For details on the PAC programme, see its web page (http://www.sigplan.org/PAC.htm) Programme Committee: ==================== David Duke (co-chair) University of Leeds, UK Yukiyoshi Kameyama (co-chair) University of Tsukuba, Japan Baris Aktemur Özyeğin University, Turkey Marco Aldinucci University of Torino, Italy Jost Berthold Commonwealth Bank, Australia Kei Davis Los Alamos National Laboratory, USA Kento Emoto Kyushu Institute of Technology, Japan Zhenjiang Hu National Institute of Informatics, Japan Ben Lippmeier University of New South Wales, Australia Rita Loogen University of Marburg, Germany Geoffrey Mainland Drexel University, USA Mike Rainey INRIA, France Mary Sheeran Chalmers University of Technology, Sweden Satnam Singh Facebook, UK

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ANNOUNCE: fadno-braids 0.0.2
by Stuart Popejoy 03 Apr '16

03 Apr '16

Braids represented as Haskell types with support for generation and transformations. Artin generators, Birman-Ko-Lee band generators, isotopy/Reidemeister moves, rendering via Diagrams. https://hackage.haskell.org/package/fadno-braids-0.0.2 Thanks, Stuart

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Fastest way to calculate all the ways to interleave two lists
by David Feuer 03 Apr '16

03 Apr '16

I ran into a fun question today: http://stackoverflow.com/q/36342967/1477667 Specifically, it asks how to find all ways to interleave lists so that the order of elements within each list is preserved. The most efficient way I found is copied below. It's nicely lazy, and avoids left-nested appends. Unfortunately, it's pretty seriously ugly. Does anyone have any idea of a way to do this that's both efficient and elegant? {-# LANGUAGE BangPatterns #-} import Data.Monoid import Data.Foldable (toList) import Data.Sequence (Seq, (|>)) -- Find all ways to interleave two lists interleave2 :: [a] -> [a] -> [[a]] interleave2 xs ys = interleave2' mempty xs ys [] -- Find all ways to interleave two lists, adding the -- given prefix to each result and continuing with -- a given list to append interleave2' :: Seq a -> [a] -> [a] -> [[a]] -> [[a]] interleave2' !prefix xs ys rest = (toList prefix ++ xs ++ ys) : interleave2'' prefix xs ys rest -- Find all ways to interleave two lists except for -- the trivial case of just appending them. Glom -- the results onto the given list. interleave2'' :: Seq a -> [a] -> [a] -> [[a]] -> [[a]] interleave2'' !prefix [] _ = id interleave2'' !prefix _ [] = id interleave2'' !prefix xs@(x : xs') ys@(y : ys') = interleave2' (prefix |> y) xs ys' . interleave2'' (prefix |> x) xs' ys -- What the question poser wanted; I don't *think* there's -- anything terribly interesting to do here. interleavings :: [[a]] -> [[a]] interleavings = foldr (concatMap . interleave2) [[]] Thanks, David

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Month in Haskell Mode March 2016
by Gracjan Polak 01 Apr '16

01 Apr '16

Welcome Haskell Mode users, Haskell Mode progress report for March 2016. For previous issue see February 2016 <https://github.com/haskell/haskell-mode/wiki/Month-in-Haskell-Mode-February…>. Reddit discussion <https://www.reddit.com/r/haskell/comments/4cx7hc/month_in_haskell_mode_marc…> . <https://github.com/haskell/haskell-mode/wiki/Month-in-Haskell-Mode-March-20…>What is Haskell Mode? Haskell Mode is an umbrella project for multiple Emacs tools for efficient Haskell development. Haskell Mode is an open source project developed by a group of volunteers constantly looking for contributions. For more information how to help see https://github.com/haskell/haskell-mode. <https://github.com/haskell/haskell-mode/wiki/Month-in-Haskell-Mode-March-20…>Important developments We have noticed that haskell-mode project on Github is steadily growing in popularity and that is clearly visible on historical growth graph: [image: History of stars on github leading to the number 700] So star us on Github, follow us on Twitter: @HaskellMode <https://twitter.com/HaskellMode>. <https://github.com/haskell/haskell-mode/wiki/Month-in-Haskell-Mode-March-20…>Issues closed in February - Implement REPL RET behaviour on previous prompts #30 <https://github.com/haskell/haskell-mode/issues/30> - Disable Indentation #90 <https://github.com/haskell/haskell-mode/issues/90> - Del/Backspace do not delete text selection in literate mode outside bird lines #379 <https://github.com/haskell/haskell-mode/issues/379> - haskell-mode-jump-to-def-or-tag Requires a running session #650 <https://github.com/haskell/haskell-mode/issues/650> - haskell-indentation-mode does not bind DEL #721 <https://github.com/haskell/haskell-mode/issues/721> - REPL does not work properly until load or reload file second time #765 <https://github.com/haskell/haskell-mode/issues/765> - Create a gifcast for interactive-haskell-mode startup #824 <https://github.com/haskell/haskell-mode/issues/824> - Getting Stack overflow in regexp matcher error in Haskell module having more than 1500loc #830 <https://github.com/haskell/haskell-mode/issues/830> - C-u C-c C-t doesn't add type signature #900 <https://github.com/haskell/haskell-mode/issues/900> - Invoke hasktags more directly #964 <https://github.com/haskell/haskell-mode/issues/964> - Find a professional template for web presence #1117 <https://github.com/haskell/haskell-mode/issues/1117> - Indenting data types seems broken and not configurable #1125 <https://github.com/haskell/haskell-mode/issues/1125> - Syntax propertize could mark layout blocks #1164 <https://github.com/haskell/haskell-mode/issues/1164> - Support non-interactive completions #1171 <https://github.com/haskell/haskell-mode/issues/1171> - Remove haskell-doc-prelude-types from haskell-doc.el #1179 <https://github.com/haskell/haskell-mode/issues/1179> - Deprecate haskell-mode-contextual-space #1182 <https://github.com/haskell/haskell-mode/issues/1182> - Paredit M-s no longer works after upgrade to 13.18 #1183 <https://github.com/haskell/haskell-mode/issues/1183> - Extend non-interactive completions for identifiers from TAGS #1184 <https://github.com/haskell/haskell-mode/issues/1184> - Syntax highlighting is broken for list comprehensions #1185 <https://github.com/haskell/haskell-mode/issues/1185> - haskell-mode and delete-trailing-whitespace delete content of buffer on save #1188 <https://github.com/haskell/haskell-mode/issues/1188> - Indentation is broken for quasiquotation with quote symbols #1189 <https://github.com/haskell/haskell-mode/issues/1189> - Error: (void-function haskell--rx-let) #1209 <https://github.com/haskell/haskell-mode/issues/1209> - Check if haskell-mode-autoloads.el really loads #1210 <https://github.com/haskell/haskell-mode/issues/1210> - haskell-ident-pos-at-point does not work for operators #1213 <https://github.com/haskell/haskell-mode/issues/1213> - REPL often hangs inside :{ and :} #1221 <https://github.com/haskell/haskell-mode/issues/1221> - haskell-mode-contextual-space binding on the wiki is preventing space insertion #1222 <https://github.com/haskell/haskell-mode/issues/1222> - Font-lock misidentifying valid non-TH haskell as quasiquote #1223 <https://github.com/haskell/haskell-mode/issues/1223> - Regression in indentation logic #1232 <https://github.com/haskell/haskell-mode/issues/1232> - Fix inferior-haskell-send-decl-post-filter #1240 <https://github.com/haskell/haskell-mode/issues/1240> - Error message when hitting space bar #1242 <https://github.com/haskell/haskell-mode/issues/1242> <https://github.com/haskell/haskell-mode/wiki/Month-in-Haskell-Mode-March-20…>Pull requests merged in February - Add haskell-interactive-copy-to-prompt. #457 <https://github.com/haskell/haskell-mode/pull/457> - Remove suggested imports completely #1121 <https://github.com/haskell/haskell-mode/pull/1121> - Stylish haskell after save #1137 <https://github.com/haskell/haskell-mode/pull/1137> - Add a test for indentation broken on a quasiquote #1190 <https://github.com/haskell/haskell-mode/pull/1190> - Remove haskell-mode-contextual-space #1191 <https://github.com/haskell/haskell-mode/pull/1191> - Add chapter about spell checking #1192 <https://github.com/haskell/haskell-mode/pull/1192> - Make haskell-indent-region do nothing #1193 <https://github.com/haskell/haskell-mode/pull/1193> - Prevent automatic haskell-doc-mode actions when point in string or comment #1195 <https://github.com/haskell/haskell-mode/pull/1195> - Treat insides of quasiquotes as strings #1196 <https://github.com/haskell/haskell-mode/pull/1196> - Add comma list test for indentation #1198 <https://github.com/haskell/haskell-mode/pull/1198> - Add c2hs mode #1199 <https://github.com/haskell/haskell-mode/pull/1199> - Change a couple hook properties #1201 <https://github.com/haskell/haskell-mode/pull/1201> - Fix some warnings #1202 <https://github.com/haskell/haskell-mode/pull/1202> - Small improvements of completion functions #1203 <https://github.com/haskell/haskell-mode/pull/1203> - Invoke hasktags more directly #1204 <https://github.com/haskell/haskell-mode/pull/1204> - Few doc improvements and a bit of refactoring #1205 <https://github.com/haskell/haskell-mode/pull/1205> - Keep window position when spellchecking #1207 <https://github.com/haskell/haskell-mode/pull/1207> - Improve fonts in manual #1208 <https://github.com/haskell/haskell-mode/pull/1208> - Makefile dependency tracking improvements #1211 <https://github.com/haskell/haskell-mode/pull/1211> - C2hs fixes #1212 <https://github.com/haskell/haskell-mode/pull/1212> - Guard against tabs in elisp files #1214 <https://github.com/haskell/haskell-mode/pull/1214> - Return removed names for backward compatibility #1215 <https://github.com/haskell/haskell-mode/pull/1215> - Handle operators in haskell-ident-pos-at-point too #1224 <https://github.com/haskell/haskell-mode/pull/1224> - Move haskell-interactive-prompt-state related definitions to haskell-utils.el #1226 <https://github.com/haskell/haskell-mode/pull/1226> - Extend static completions with candidates from tags table #1228 <https://github.com/haskell/haskell-mode/pull/1228> - Update completion section #1230 <https://github.com/haskell/haskell-mode/pull/1230> - Small docs improvements #1233 <https://github.com/haskell/haskell-mode/pull/1233> - Remove unused indent-region from menu #1236 <https://github.com/haskell/haskell-mode/pull/1236> - Be more strict about quasi quoter names #1239 <https://github.com/haskell/haskell-mode/pull/1239> - Use plain syntax in inferior-haskell-send-decl-post-filter #1241 <https://github.com/haskell/haskell-mode/pull/1241> <https://github.com/haskell/haskell-mode/wiki/Month-in-Haskell-Mode-March-20…>Contributors active in February Arthur Fayzrakhmanov (Артур Файзрахманов), Artyom, Fice T, Gracjan Polak, Sergey Vinokurov <https://github.com/haskell/haskell-mode/wiki/Month-in-Haskell-Mode-March-20…> Contributing Haskell Mode needs volunteers like any other open source project. For more information see: https://github.com/haskell/haskell-mode/wiki Also drop by our IRC channel: #haskell-emacs at irc.freenode.net. Thanks!

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Haskell hacking internships at LANL (Fall 2016, undergraduate)
by Kei Davis 01 Apr '16

01 Apr '16

We have an ongoing project developing an auto-parallelizing pure functional language implementation using GHC as the front end to dump Core or STG (much like Intel's approach here http://www.leafpetersen.com/leaf/publications/hs2013/hrc-paper.pdf) If you are a United States citizen or permanent resident alien studying computer science or mathematics at the undergraduate level with strong interests in Haskell programming, compiler/runtime development, and pursuing a fall semester (2016) internship at Los Alamos National Laboratory this could be for you. We don't expect applicants to necessarily already be highly accomplished Haskell programmers--such an internship is expected to be a combination of (further) developing your programming/Haskell skills and putting them to good use. If you're already a strong C hacker we could use that too. The application deadline is May 31, 2016. It's a bit of a process so don't leave inquiries until the last day. Email me if interested in more information, and feel free to pass this along. -- Kei Davis kei(a)lanl.gov Applied Computer Science Group CCS-7, Mail Stop B287 Los Alamos National Laboratory Los Alamos, NM 87545, U.S.A.

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[TFP 2016] Final call for papers
by Peter Achten 01 Apr '16

01 Apr '16

----------------------------- C A L L F O R P A P E R S ----------------------------- ======== TFP 2016 =========== 17th Symposium on Trends in Functional Programming June 8-10, 2016 University of Maryland, College Park Near Washington, DC http://tfp2016.org/ The symposium on Trends in Functional Programming (TFP) is an international forum for researchers with interests in all aspects of functional programming, taking a broad view of current and future trends in the area. It aspires to be a lively environment for presenting the latest research results, and other contributions (see below). Authors of draft papers will be invited to submit revised papers based on the feedback receive at the symposium. A post-symposium refereeing process will then select a subset of these articles for formal publication. TFP 2016 will be the main event of a pair of functional programming events. TFP 2016 will be accompanied by the International Workshop on Trends in Functional Programming in Education (TFPIE), which will take place on June 7nd. == INVITED SPEAKERS == TFP 2016 is pleased to announce keynote talks by the following two invited speakers: * Ronald Garcia, University of British Columbia * Steve Zdancewic, University of Pennsylvania == HISTORY == The TFP symposium is the heir of the successful series of Scottish Functional Programming Workshops. Previous TFP symposia were held in * Edinburgh (Scotland) in 2003; * Munich (Germany) in 2004; * Tallinn (Estonia) in 2005; * Nottingham (UK) in 2006; * New York (USA) in 2007; * Nijmegen (The Netherlands) in 2008; * Komarno (Slovakia) in 2009; * Oklahoma (USA) in 2010; * Madrid (Spain) in 2011; * St. Andrews (UK) in 2012; * Provo (Utah, USA) in 2013; * Soesterberg (The Netherlands) in 2014; * and Inria Sophia-Antipolis (France) in 2015. For further general information about TFP please see the TFP homepage. (http://www.tifp.org/) == SCOPE == The symposium recognizes that new trends may arise through various routes. As part of the Symposium's focus on trends we therefore identify the following five article categories. High-quality articles are solicited in any of these categories: Research Articles: leading-edge, previously unpublished research work Position Articles: on what new trends should or should not be Project Articles: descriptions of recently started new projects Evaluation Articles: what lessons can be drawn from a finished project Overview Articles: summarizing work with respect to a trendy subject Articles must be original and not simultaneously submitted for publication to any other forum. They may consider any aspect of functional programming: theoretical, implementation-oriented, or experience-oriented. Applications of functional programming techniques to other languages are also within the scope of the symposium. Topics suitable for the symposium include, but are not limited to: Functional programming and multicore/manycore computing Functional programming in the cloud High performance functional computing Extra-functional (behavioural) properties of functional programs Dependently typed functional programming Validation and verification of functional programs Debugging and profiling for functional languages Functional programming in different application areas: security, mobility, telecommunications applications, embedded systems, global computing, grids, etc. Interoperability with imperative programming languages Novel memory management techniques Program analysis and transformation techniques Empirical performance studies Abstract/virtual machines and compilers for functional languages (Embedded) domain specific languages New implementation strategies Any new emerging trend in the functional programming area If you are in doubt on whether your article is within the scope of TFP, please contact the TFP 2016 program chair, David Van Horn. == BEST PAPER AWARDS == To reward excellent contributions, TFP awards a prize for the best paper accepted for the formal proceedings. TFP traditionally pays special attention to research students, acknowledging that students are almost by definition part of new subject trends. A student paper is one for which the authors state that the paper is mainly the work of students, the students are listed as first authors, and a student would present the paper. A prize for the best student paper is awarded each year. In both cases, it is the PC of TFP that awards the prize. In case the best paper happens to be a student paper, that paper will then receive both prizes. == SPONSORS == TFP is financially supported by CyberPoint, Galois, Trail of Bits, and the University of Maryland Computer Science Department. == PAPER SUBMISSIONS == Acceptance of articles for presentation at the symposium is based on a lightweight peer review process of extended abstracts (4 to 10 pages in length) or full papers (20 pages). The submission must clearly indicate which category it belongs to: research, position, project, evaluation, or overview paper. It should also indicate which authors are research students, and whether the main author(s) are students. A draft paper for which ALL authors are students will receive additional feedback by one of the PC members shortly after the symposium has taken place. We use EasyChair for the refereeing process. Papers must be submitted at: https://easychair.org/conferences/?conf=tfp2016 Papers must be written in English, and written using the LNCS style. For more information about formatting please consult the Springer LNCS web site: http://www.springer.com/computer/lncs?SGWID=0-164-6-793341-0 == IMPORTANT DATES == Submission of draft papers: April 8, 2016 Notification: April 15, 2016 Registration: May 13, 2016 TFP Symposium: June 8-10, 2016 Student papers feedback: June 14, 2016 Submission for formal review: July 14, 2016 Notification of acceptance: September 14, 2016 Camera ready paper: October 14, 2016 == PROGRAM COMMITTEE == Amal Ahmed Northeastern University (US) Nada Amin École Polytechnique Fédérale de Lausanne (CH) Kenichi Asai Ochanomizu University (JP) Malgorzata Biernacka University of Wroclaw (PL) Laura Castro University of A Coruña (ES) Ravi Chugh University of Chicago (US) Silvia Ghilezan University of Novi Sad (SR) Clemens Grelck University of Amsterdam (NL) John Hughes Chalmers University of Technology (SE) Suresh Jagannathan Purdue University (US) Pieter Koopman Radboud University Nijmegen (NL) Geoffrey Mainland Drexel University (US) Chris Martens University of California, Santa Cruz (US) Jay McCarthy University of Massachusetts, Lowell (US) Heather Miller École Polytechnique Fédérale de Lausanne (CH) Manuel Serrano INRIA, Sophia-Antipolis (FR) Scott Smith Johns Hopkins University (US) Éric Tanter University of Chile (CL) David Van Horn (Chair) University of Maryland (US) Niki Vazou University of California, San Diego (US) Stephanie Weirich University of Pennsylvania (US)

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Deriving Eq and Show instances for testing
by Anakreontas 01 Apr '16

01 Apr '16

I have datatypes for which I need an Eq and Show instance only for testing. I could derive those instances in the datatype declaration but I prefer not to add unnecessary functionality. With StandaloneDeriving extension I can derive the instances in the test module but this produces many warning about orphan instances. Is there a better approach or a way to stop reports about orphan instance warnings? Regards

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Re: [Haskell-cafe] [Haskell] Postdoc ad: quantum-computing programming languages
by Jerzy Karczmarczuk 01 Apr '16

01 Apr '16

Hello. Le 31/03/2016 22:04, Scott Pakin a écrit : > My institution just bought a D-Wave 2X adiabatic quantum computer. > The problem is, no one really has a grasp on how to *program* an > adiabatic quantum computer. It's a totally different beast from the > gate-model quantum computers that most people imply when they talk > about quantum computing. I find all this a bit disturbing... Los Alamos buys an expensive device that nobody knows how to use?? Moreover, in circumstances where the doubts about the real performance of the D-Wave computer stii persist? Several physicists refuse to call this contraption a "quantum computer". The statements about their "qubits" in their public materials are not always serious, there is practically nothing about a genuine state superposition, no educated physicist will buy such pseudo-definition as "having simultaneously the values 0 and 1" (being the result of two currents flowing in opposite directions ; what about phase?). Their "white paper" about the map colouring shows a model which is more similar to a Hopfield (or similar) neural network, rather than a quantum computing device. The optimization is a natural application domain of such networks, but where are some more universal examples? Surely, there are quantum elements in it: superconducting niobium rings, Josephson junctions, etc. But, actually, even a plain transistor is a quantum device as well, and nobody dares to call it a "qubit". Their native code seems to be extremely far from quantum theory, as we know it. = But, if the device works, has some affinities with neural stuff and with Monte-Carlo techniques (annealing), perhaps a good playground for testing it would be a Go player? Jerzy Karczmarczuk

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introspection -- towards type algebra
by Rustom Mody 01 Apr '16

01 Apr '16

I am looking for how far algebra on types in the manner of "set theory as an algebra" ¹ is possible. So for example in set theory one can compute for sets S, T S∪T, S∩T, S-T etc Is something similar possible for types? Say I have data Primary = Red|Green|Blue data Othercolors = Violet|Indigo|Yellow|Orange I want something like Rainbow = Primary ∪ Othercolors Equivalently if Rainbow and Primary had been defined, how to get/compute Rainbow - Primary? ------------------------- I thought the first-class types in Idris would be a good bet to try out at least a trivial prototype. Seems not... So asking here. Clearly and obviously one can use haskell to implement any language. My question is what/which are the introspective libraries/features of modern haskell that make this easy and lightweight. Thanks Rusi ¹ Yeah the term 'type algebra' may be taken in the sense of algebraic data types Cant think of a better one

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