March 2010 - Boost - lists.boost.org

[intrusive doc] slist says that both push_front and push_back are constant-time
by Andy Venikov 31 Mar '10

31 Mar '10

The doc for slist says that if using non-constant size semantics, the size of the slist is the size of a single pointer. That means that either push_front or push_back cannot be constant time since we first need to find it. Am I missing something? Thanks, Andy.

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[1.43.0] Cutoff for major code changes approaching
by Beman Dawes 31 Mar '10

31 Mar '10

The cutoff date for major code changes is this weekend, so please complete any pending merges to the release branch. Also, now might be a good time to check the release regression tests and inspection reports to make sure your library is in good shape: http://beta.boost.org/development/tests/release/developer/summary.html http://boost.cowic.de/rc/inspect-snapshot.html PS: The beta is scheduled for April 17th, and the release for May 1. The calendar can be seen at: http://www.boost.org/development/index.html -- The Release Managers, Beman Dawes Daniel James Eric Niebler Rene Rivera Vladimir Prus

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Proposal for semantic graph : Boost Mentors, please comment on it
by Chinmaya Poswalia 31 Mar '10

31 Mar '10

*Need For Semantic Graph* First thing I would like to mention is that semantic graph is not merely a graph with links and nodes. It’s a graph in which nodes links can be of different data types and similarly links. It's a graph of interconnected things that is machine-understandable, its meaning or "semantics" can be explicitly represented on any common database, just like its data. This is the real way to make social networks, applications, libraries and information/data open. Merely opening up their API's is just the first step. Through it, applications can start using the functions and properties written in other languages. Since the Semantic Library makes data-integration easier, it will ultimately be widely adopted and will cater most to the community. Simply put, applications that wish to access or integrate data in the modern age can more easily be done. That alone is reason enough to use this library. Summarising the above Ø Making data more accessible, connectable, and reusable across applications would be a huge benefit. Ø Ability to do more sophisticated reasoning across data. Ø Applications in which its use can directly be seen is World Wide Web. Please refer the above link for more detail. http://novaspivack.typepad.com/nova_spivacks_weblog/2007/11/defining-the-se… http://www.signosemio.com/rastier/a_graphe.asp *Project Proposal* [dog] <- (ERG) <- [bite] -> (ACC) -> [man] <---------------------- Semantic Graph Here dog, bite and man all are of different types and ERG and ACC are the relations where ERG -> *corresponds to the ergative case (the agent of an action)* ACC-> to* the accusative case (the patient of an action, the one affected by it)* I am aiming to make the first steps towards the conceptualization and formulation of Semantics Graphs for the Boost Graph Library (BGL). *1) **Node Data Structure* Node should have a container to store data and an array of functions whose scope will be limited to only process the data of its own node and attached links. These nodes can process their data individually and this functionality would be defined by the functions which user would provide through the array of functions and can transmit request for processing to another nodes through links joined to them. Nodes will also contain the pointer to all the links leaving it. *2) **Link Data Structure* Links apart from containing data it will contain some defined constants whose actions value would be provided at the start time and should. These constants would define the relation between the nodes it is connecting to. Majorly relations would include of the following types like who is the agent of action, who is the recipient of action, which is the proposed result of the action, what is the final result, what is the beneficiary action and who is the beneficent of the action, who is the comparing element and who is being compared. The following paper clearly states what semantic graph is mathematically. http://www.revue-texto.net/Parutions/Livres-E/Hebert_AS/12.Semantic-Graph.p… *3) **Algorithms For Traversal of The Graph* Here I want to state that I found a library for semantic graphs which is in the CLI library. It can be obtained at http://www.codesynthesis.com/~boris/tmp/cli/cli-0.0.2+dep.tar.bz2<http://www.codesynthesis.com/%7Eboris/tmp/cli/cli-0.0.2+dep.tar.bz2> The basic algorithm of Traversal can be used but here since the nodes and links are of different data types, this can be implemented with the help of a void pointer. Once we reaches a node, we will mark it explore and the will move to the links that leaves it. This will even provide the functionality to enable us to find a link. How knowledge will be represented and how what variables and functions need to be implemented, these issues and their solution are clearly stated in the following research paper. http://www.edmondchow.com/pubs/SS105ChowE.pdf An application of semantic sub-graph involving knowledge representation and text summarisation is given in the following paper written under Microsoft Research. http://nl.ijs.si/isjt04/zbornik/sdjt04-05leskovec.pdf Please note the fact that through this way, i think the space occupied by the graph is minimal as it only depends on the containers used by the user. We just used 3 pointers for linking the nodes.

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[concept_check] silence gcc warnings
by Jürgen Hunold 31 Mar '10

31 Mar '10

Hi ! I've started to use Boost.Accumulators and I'm getting tons of ugly warnings when compiling with optimization on. See full "warn.log" for details, This boils down to boost/concept_check.hpp 335: warning: non-static reference ‘const float& boost::UnaryFunction<boost::numeric::functional::as_max<const float, void>, float, const float&>::arg’ in class without a constructor [-Wuninitialized] when the check ist called with a reference parameter. It seems that providing a dummy constructor is sufficient to silence this. Please find a patch attached. Okay to commit ? Or are the better ideas ? Yours, Jürgen -- * Dipl.-Math. Jürgen Hunold ! Ingenieurgesellschaft für * voice: ++49 511 262926 57 ! Verkehrs- und Eisenbahnwesen mbH * fax : ++49 511 262926 99 ! Lister Straße 15 * juergen.hunold(a)ivembh.de ! www.ivembh.de * * Geschäftsführer: ! Sitz des Unternehmens: Hannover * Prof. Dr.-Ing. Thomas Siefer ! Amtsgericht Hannover, HRB 56965 * PD Dr.-Ing. Alfons Radtke !

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Google Summer Of Code
by Brian Bartman 30 Mar '10

30 Mar '10

Hello my name is Brian Bartman and I am an undergraduate at Kent State University Majoring in computer science. I was interested in the bits & ints project, specifically Compressed array and Compressed vector as well as the utilities for bit mask manipulation. Could some one help me better understand the requirements of this project? I would like to draft a proposal for GSoC 2010 and wanted to better understand the project before I write a proposal.

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Re: [boost] [MSM] using irow "internal transitions" and constructorarguments for frontend ?
by Christophe Henry 30 Mar '10

30 Mar '10

Hi, >We have seen that there was a review early this year is there a boost >version where msm will be officially part of boost lib ?. I'm finishing it and hope to bring it into the 1.43. Hopefully, the newest version will be online in a few days. If you cannot wait, I can send it to you before. >Is anybody used boost::msm in a real life project is there any >measures about stability ?. I did but I'm biased ;-) Seriously, I know a few people who did and reported here and there a bug (which is usually corrected very fast) but nothing critical. I'd also be interested in live reports. >Furthermore we had the following problems during our evaluation: > >1.) in the documentation there is a section about internal transitions >using irow : I think this is in the documentation from the sandbox, not the vault. The doc in the sandbox is not up to date because I made an almost full rewrite. MSM 2.0 supports no internal transitions, but the subject was brought by Michael Caisse during the review and the coming version 2.10 has them. The sandbox version also has internal transitions and is usually up to date, except, as I said, the doc (but not for long). >2.) State machine constructor with arguments in the documentation >there is an example but we did not managed to get it working > >is this example correct in the documentation ?. The example is correct and should work but I admit I'm unsure if it was already in the 2.0. I guess not. Please try the sandbox or the coming 2.10. But thanks for telling me, I just realize I forgot this part in the new doc, so I will add it. Thanks, Christophe

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BoostCon2010 lodging - M4MW
by Robert Ramey 30 Mar '10

30 Mar '10

I'm making arrangements to attend BoostCon2010. I'm reviewing the Aspen Meadows Resort web page. Seems like a very fancy and nice setup. The rates are $159 + 10% + $18 / day for one or two persons. I expect to be going by myself as my wife considers attendance at such an event as boring beyond belief. I'm also a free lance software developer so I will be paying myself. So it would be economically advantageous for me to share this with at least one other person (The room has a capacity up to 4 persons). So anyone who want's to split this with me should let me know via private email ramey(a)rrsd.com. BTW- I'm still considering options about getting there. I haven't been on an airplane since 1995. From what I hear, it's even more unpleasant now than it was then. But it's a long drive from where I live. Anyway ... Robert Ramey

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Boost.Graph GSoC 2010
by Cezary Bartosiak 30 Mar '10

30 Mar '10

Hi, I am Cezary, a student of computer science at the Cybernetics Faculty, Military University of Technology, Warsaw. I am interested in developing the BGL. I've got an idea related to the Topology Generators. I have participated in a project concerning epidemics spreading and, as a part of the project, we have implemented several social networks generators (Barabási–Albert model for instance). I hit upon an idea to implement these algorithms apart from proposed topology generators. I know that Boost.Graph contains some algorithms for generating networks, I would like to add some extensions: 1. There is Erdős-Rényi model generator in two versions G(n, p) and G(n, m). I think I could provide some additional implementations for specific cases, I mean: a) Fast generator of sparse graphs inspired by http://www.inf.uni-konstanz.de/algo/publications/bb-eglrn-05.pdf. b) Fast generator of dense graphs, algorithm by Keith M. Briggs Mar 31, 2006 (the only implementation of this one I've seen in NetworkX library). 2. There is only Beta-model generator of Small World network in the library. I would like to add Alfa-model generator as well as Kleinberg model generator. Here are some interesting materials: http://tam.cornell.edu/tam/cms/manage/upload/SS_nature_smallworld.pdf http://www.bsos.umd.edu/socy/alan/stats/network-grad/summaries/Watts-Six%20… http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.83.381&rep=rep1&ty… 3. At the moment we've got only PLOD algorithm to generate ScaleFree networks. I could provide other ones: a) Basic generator often seen in popular libraries, for instance NetworkX. b) Generalized generator with probabilities of adding new edges and rewiring existing ones. c) Simplified models generators: A (uniform attachment) and B (no growth). Coming back to Topology Generators I would implement them for some "basic" topologies, let's say: path, star, cycle, wheel, ladder, grid, hypercube, barbell, complete, frucht and many others if time remains... I would be glad to know your opinion. Best, Cezary

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[GSoC] Advanced data structures library
by Rui Gonçalves 30 Mar '10

30 Mar '10

Hello, I'm new to this community. My name is Rui Gonçalves and I'm thinking about submitting an application to Boost in Google Summer of Code. In particular, due to my own programming interests in data structures, generic programming and abstraction layer developing in general, I would be very happy in developing an advanced data structures library. As suggested in the ideias page, it would have includes various types of heaps and queues. I haven't had time to look at all different libraries, but if there is some known data structure with implementation needed, I would not mind implementing that too. I had a look at the /boost/pending available implementations. A lot of code could be reused / ported; however, I think that the source code could be more standardized between heap implementations. I'm thinking in a STL-like implementation, like: template < class T, class Heap = binary_heap<T>, class Compare = less<T> > class priority_queue; template < class T, class Container = vector<T>, class Compare = less<T> > class fibonacci_heap; I already looked in books for some more obscure details of each algorithm, and haven't found anything excessively difficult. This seems a rather simple project (although I recognize it can take some time). Is there some convention or requirements for data structures in Boost? Is there any difficulty that I should be aware of but didn't notice, or any detail about GSoC that I should know? (I'm new to that program and I feel kind of lost). Thank you in advance for your help, Rui Gonçalves

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[MSM] using irow "internal transitions" and constructor arguments for frontend ?
by Richard Szabo 30 Mar '10

30 Mar '10

Hi All We are in a process to evaluate boost::msm 2.0 we would like to use it in our project. We were using sources from http://www.boostpro.com/vault/index.php?directory=Msm version 2.0. We have seen that there was a review early this year is there a boost version where msm will be officially part of boost lib ?. Is anybody used boost::msm in a real life project is there any measures about stability ?. Furthermore we had the following problems during our evaluation: 1.) in the documentation there is a section about internal transitions using irow : see : irow < Empty , cd_detected , &p::internal_action ,&p::internal_guard > but we did not find the irow definition in the sources ?. 2.) State machine constructor with arguments in the documentation there is an example but we did not managed to get it working is this example correct in the documentation ?. struct player_ : public msm::front::state_machine_def<player_> { player_(int some_value){…} } This is still possible, using the back-end as forwarding object: typedef msm::back::state_machine<player_ > player; player p(3); // do something with the state machine Thanks in Advance Richie & Michi

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