March 2010 - Boost - lists.preview.boost.org

[contract] Macro syntax?
by Lorenzo Caminiti 08 Apr '10

08 Apr '10

Hello all, I would like you to vote between one of the two options below. Which option do you prefer? (-) OPTION 1 requires programmers to repeat the function signature tokens twice -- in the function declaration and in the CONTRACT_FUNCTION() macro. (+) However, OPTION 1 seems to make the code more readable -- users not familiar with Boost.Contract can "skip" the tokens in the CONTRACT_FUNCTION() signature-sequence and just read the usual C++ function declaration. OPTION 1: The function declaration is programmed using the usual C++ syntax just before the CONTRACT_FUNCTION() macro. template<typename T> class myvector { CONTRACT_INVARIANT( ({ ... }) ) public: void push_back(const T& element) // Usual C++ push_back() declaration. CONTRACT_FUNCTION( (class) (copyable)(myvector) (public) (void) (push_back)( (const T&)(element) ) (precondition)({ ... }) (postcondition)({ ... }) (body)({ ... }) ) ... }; OPTION 2: The CONTRACT_FUNCTION() macro automatically programs also the function declaration. template<typename T> class myvector { CONTRACT_INVARIANT( ({ ... }) ) public: // No usual C++ push_back() declaration here. CONTRACT_FUNCTION( (class) (copyable)(myvector) (public) (void) (push_back)( (const T&)(element) ) (precondition)({ ... }) (postcondition)({ ... }) (body)({ ... }) ) ... }; Thank you. Lorenzo

4 7

[Review Results] Boost.Polygon library accepted into boost
by Fernando Cacciola 07 Apr '10

07 Apr '10

Dear Boosters, [first of all allow me to apology for not doing this before. My small consulting bussines suddenly grew out of proportion and now is way over my head, keeping me working/managing 16 hours a day] I am pleased to announce that the Boost.Polygon library from Lucanus Simonson has been accepted into boost provided some of the most critical concerns, detailed below, are addressed first. First of all I would like to thank Lucanus and Intel Corporation for making this work available to all C++ developers around the world. I would also like to thank all the reviewers that participated (in no particular order nor degree of participation) Thomas Klimpel Frank Mori Hess Barend Gehrels Andreas Fabri Jeffrey Hellrung Tim Keitt Markus Werle Paul A. Bristow Robert Stewart Mathias Gaunard Michael Fawcett Steven Watanabe Joachim Faulhaber John Bytheway Sebastian Redl Mika Heiskanen John Phillips Kai Benndorf Hartmut Kaiser Arash Partow Maurizio Vitale Brandon Kohn David Abrahams Gordon Woodhull Daniel James John Maddock Tom Brinkman Bo Persson Mateusz Loskot Christian Henning Jean-Sebastien Stoezel The library had 6 yes votes and 4 no votes. Those who voted no made the following major complains and remarks (they are numbered as I will refer to them back later): Barend Gehrels: (1) According to his benchmarks, intersection algorithms are unnecesarily slow as if something where fundamentally wrong in the design and/or implementation. AFAICT the implication has not been proved or disproved so far, hence I consider it a red herring and cannot take it as a reason for rejecting the library, but it is important to look at it in detail. (2) As a major complain, the library is unusable in those domains where floating point support is a requirement (like GIS). (3) The library should contain some basic polygon geometry algorithms such as convex hull and centriod Phil Endecott: (4) There is no concept checking in the code so it is difficult to adapt. (5) There where too many warnings and build errors (but Luke fixed these) (6a) The documentation needs a better overview of operations supported by the concetps. (6b) It also needs the details on the algorithms complexities. (6c) It also misses the numerical requirements for the coordinate type. (6d) And tutorials. (7) Some operators are ambiguous and it would be better to keep just one of each "flavor". (8) The polygon_data template class is parameterized by a coordiante type rather than a point type. This makes it useless for integration with existing geometric data types Michael Fawcett: (5), (6a), (6d) (9) T9he API should provide versions using output iterators in addition to output container references. (10) Theoreticall the library would be usable with a user defined coordinate type (metting certain requirements now undocumented), for example a fixed point data type, but some details in the internal design and implementation prevents this. (11) As a major complain, the library is unusable in those domains where floating point support is a requirement (like GIS). Hartmut Kaiser: (11), (1) Fernando Cacciola: (12) The name of the library should change to better indicate that is restricted to Integral coordinates and two-dimensions. (13) The documentation must contain a "credits" section acknowledging all the people that participated in the review. For the library to be effectively accepted, points (5),(6a-d),(10), (12) and (13) should properly addressed ((5) is already done AFAICT) It would be quite significant if point (1) where looked into. Once again I thank Lucanus, Intel Corporation and all the reviwers. Best regards -- Fernando Cacciola SciSoft Consulting, Founder http://www.scisoft-consulting.com

4 4

[google summer of code] student
by Cezary Bartoszuk 05 Apr '10

05 Apr '10

Hello, I am a CS student and I would like to patricipate in developing Heaps & Queues in Boost during Google Summer Of Code '10. Where, besides the source code, should I search for information about what's already in Boost (in the meaning of heaps/queues)? Who should I talk to about participating in Boost? Best regards, Cezary Bartoszuk, --- Faculty of Mathematics Informatics and Mechanics, University of Warsaw, Poland

3 4

Interested in Boost.Graph
by Piyush Garg 05 Apr '10

05 Apr '10

hi I am interested in upgrading the boost graph library to parallel boost graph library. I want to ask that do i have to chose one of the projects in boost.graph or i have to make them all during summer. Can i make the project on that or i have to suggest my own idea? Thanks Piyush Garg.

3 7

GSoC: Enforcing Code Feature Requirements
by vicente.botet 03 Apr '10

03 Apr '10

Hi, I have recently reread the article "Enforcing Code Feature Requirements in C++" by Scott Meyers <http://www.artima.com/cppsource/codefeaturesP.html> I have posted some ideas that could improve the design (<http://www.artima.com/forums/flat.jsp?forum=226&thread=238798&start=0#372622>) I wanted to know if this could be a good subject for GSoC, if the approach I purpose to solve some issues is acceptable and if there is some students interested. Of course any comments are welcome. Best, _____________________ Vicente Juan Botet Escribá

7 14

[contract] Released Contract Programming Library on SourceForge
by Lorenzo Caminiti 02 Apr '10

02 Apr '10

Hi all, I have released on SourceForge a library that implements Contract Programming (a.k.a. Design by Contract(TM) ) for C++. I am considering to submit this library to Boost (as Boost.Contract). Contract++ Library * Download http://sourceforge.net/projects/dbcpp/ * Documentation http://dbcpp.sourceforge.net/ * Examples http://dbcpp.sourceforge.net/contract__/examples.html Comments? Regards, Lorenzo

2 9

[mpl] has_function
by Lorenzo Caminiti 02 Apr '10

02 Apr '10

Hello all, Is there a way I can check if a class has a given member function using metaprogramming? What I need is to check at compile-time if a function is overriding a virtual function or not. In the example below, z::f is overriding x::f but not y::f (which does not exist) and the compiler knows that -- is there a way I can extract that information from the compiler? struct has_function<class Base, ... /* other parameters */ > { ... /* some implementation */ }; struct x { virtual void f() {} }; struct y { virtual void g() {} }; struct z: x, y { void f() { cout << has_function<x, &z::f>::value << endl; // print 1 cout << has_function<y, &z::f>::value << endl; // print 0 } }; (This does not compile -- I do not know how to program it so it compiles -- but it should give the idea of what I am looking for.) Thank you very much. Lorenzo

16 27

[range][string_algo] Conflict between algorithm names
by Jeremiah Willcock 02 Apr '10

02 Apr '10

When I try to include both Boost.Range algorithms (in the current trunk version) and Boost.Algorithm, using a file such as the following: #include <boost/algorithm/string.hpp> #include <boost/range/algorithm.hpp> I receive several errors about duplicate definitions. I am using gcc 4.1.2 on Linux. ./boost/range/algorithm/find.hpp:28: error: ‘template<class SinglePassRange, class Value> typename boost::range_iterator::type boost::find(SinglePassRange&, const Value&)’ conflicts with previous using declaration ‘template<class RangeT, class FinderT> boost::iterator_range<typename boost::range_iterator<C>::type> boost::algorithm::find(RangeT&, const FinderT&)’ ./boost/range/algorithm/lexicographical_compare.hpp:28: error: ‘template<class SinglePassRange1, class SinglePassRange2> bool boost::lexicographical_compare(const SinglePassRange1&, const SinglePassRange2&)’ conflicts with previous using declaration ‘template<class Range1T, class Range2T> bool boost::algorithm::lexicographical_compare(const Range1T&, const Range2T&)’ ./boost/range/algorithm/lexicographical_compare.hpp:42: error: ‘template<class SinglePassRange1, class SinglePassRange2, class BinaryPredicate> bool boost::lexicographical_compare(const SinglePassRange1&, const SinglePassRange2&, BinaryPredicate)’ conflicts with previous using declaration ‘template<class Range1T, class Range2T, class PredicateT> bool boost::algorithm::lexicographical_compare(const Range1T&, const Range2T&, PredicateT)’ The using declarations mentioned in the error message are in files such as boost/algorithm/string/find.hpp. Is there a workaround or easy fix for this? -- Jeremiah Willcock

5 10

Transfer of Maintenance Rights
by Stewart, Robert 01 Apr '10

01 Apr '10

Dave asked for a policy proposal for how Boost library maintenance rights may be transferred. Edward Diener declined, so I'll offer one and go a little further while I'm at it. Consider the following as a replacement for the text at <http://www.boost.org/community/reviews.html#Maintainer>. _____________________________ Library Author's Responsibilities By submitting a library to Boost, you agree to put the library and its documentation under a Boost-compatible license, if it is accepted. If your library is accepted, you are free to change it any way you wish. Indeed, we encourage you to make constant improvements. However, because peer review is an important part of the Boost process, please consider getting Boost community feedback before making substantial changes to the interface of your library. Furthermore, if your library is accepted, you agree to be the library maintainer or to find a qualified volunteer to serve in your stead. You may, of course, assemble a qualified group to act as maintainers of your library, regardless of whether you continue to be a maintainer. Library Maintainer's Rights and Responsibilities As a library maintainer, you agree to provide timely support to users of the library, and to fix bugs and release those fixes in a timely fashion. You also agree to consider making library enhancements and improvements. Note that others may offer and even commit patches to a library you maintain, provided the patch is posted to the Boost Developer's mailing list for approval and is not rejected by anyone within a reasonable time. If you find that you can no longer fulfill your responsibilities as maintainer of a library, you are responsible to advertise this to the Boost community. If you are the sole maintainer, you are responsible to find a replacement. If for some reason you fail to fulfill your responsibilities as maintainer of a library, as judged by the Boost community, whether through willful neglect or otherwise, you agree to allow the Boost community to provide a suitable replacement. _____ Rob Stewart robert.stewart(a)sig.com Software Engineer, Core Software using std::disclaimer; Susquehanna International Group, LLP http://www.sig.com IMPORTANT: The information contained in this email and/or its attachments is confidential. If you are not the intended recipient, please notify the sender immediately by reply and immediately delete this message and all its attachments. Any review, use, reproduction, disclosure or dissemination of this message or any attachment by an unintended recipient is strictly prohibited. Neither this message nor any attachment is intended as or should be construed as an offer, solicitation or recommendation to buy or sell any security or other financial instrument. Neither the sender, his or her employer nor any of their respective affiliates makes any warranties as to the completeness or accuracy of any of the information contained herein or that this message or any of its attachments is free of viruses.

25 51

[bgl] Reconnecting an edge
by Matthias Walter 01 Apr '10

01 Apr '10

Hi! Is there any way to reconnect an edge in a graph? I'm interested in doing so while retaining a property map. Thus remove_edge and add_edge are not a solution, I think. If not, may it worth to add such a concept? best regards Matthias Walter

3 3

[GSoC 2010] Boost.Graph topology generators
by Omair Mohammed Abdullah 01 Apr '10

01 Apr '10

Hi, I am interested in implementing topology generators for Boost.Graph. I have a few questions: What is the scope of this project? Is it expeced to implement the common topologies with detection methods or more? For example, are generators like PLOD, Erdos-Renyi and small-world are already there. Are we supposed to extend them?

2 1

Second iteration of Boost.XInt library uploaded, requesting further comments
by Chad Nelson 01 Apr '10

01 Apr '10

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I've just uploaded the second iteration of the Boost.XInt library to the Boost Vault. I very much appreciate all of the comments and suggestions everyone has offered on the first one, and I've incorporated a number of them. Maybe I'm just a masochist, but please take a look and let me know what you think. - -- Chad Nelson Oak Circle Software, Inc. * * * -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkuypFUACgkQp9x9jeZ9/wRD3wCeMKRKaeml9UzhMNTpl15RvBFE pw8AniN8kkXNEFelgY4VYtWNzaCi88cV =lHLU -----END PGP SIGNATURE-----

5 13

[lock-free] CDS -yet another lock-free library
by Khiszinsky, Maxim 01 Apr '10

01 Apr '10

Hi, I'd like to present to boost community the CDS (Concurrent Data Structure) C++ library at libcds.sourceforge.net. It is an attempt to generalize well-known lock-free (and a few lock-based) data structures discovered by famous researches (M.Michael, N.Shavit and others). The library is mostly header-based, only the kernel of light-weight memory managers is resided in small dynamic library. The CDS library supports a set of modern processor architectures: x86, amd64, ia64, sparc; compiler supported is GCC 4 and MS Visual C++ 2008. The last CDS release 0.6.0 is developed close to C++ Memory Model proposal. I need the recommendations from boost community about : 1. Are the atomic primitives implemented correct for each of supported processor?.. I'm not an expert in this area... 2. Is the memory order constraint (from C++1x proposal) choosed correctly for lock-free data structure implementation?.. I known it is very large and magic question. Maybe, somebody analyzes the library code and find the errors. And I be very glad if anybody joins to CDS project. It is very interesting area of computing science with nonstandard algorithms and crazy implementation (and debugging notably).

9 35

GSOC Application Dates.
by swagat konchada 31 Mar '10

31 Mar '10

Does Boost suggest submitting the proposals for GSOC'10 as early as possible? Or is it ok if I take time? -- Problem is a phenomenon indicating lack of thought. Swagat Konchada

2 1

GSOC BigInt Numeric_adaptor
by swagat konchada 31 Mar '10

31 Mar '10

> swagat konchada wrote: > > > If we consider performance issues based on design, planning the > > BigInt architecture could be designed in two ways > > > > 1. 3 layers to allow optional binding to Boost's own bigint, > > GMP, or anyother bigint library, for the user during compile > > time. > > > > 2. 2 layers if we plan to limit Boost.Bigint's options to only > > itself and GMP. > > [snip] >IMO you should look at the discussion on a numeric_adaptor by Barend Gehrels and some draft code mentioned in > http://archive.freebsd.se/?ml=freebsd-questions&a=2007-05&m=11343770<http://archive.freebsd.se/?ml=freebsd-questions&a=2007-05&m=11343770> >to get some idea of the problem and a plausible framework which might include 'BoostsOwnBigInt' as an alternative to GMP >etc. >Paul >PS But you should also be aware that another xInt project is being discussed on this group. I checked out the numeric_adaptor scheme. It has used the GMP library and the CLN library's API to optionally provide some basic arithmetic operators on arbitrary precision decimal numbers(it was surprising since i expected adaptation for integer operations first, though i realise that there'd be no much change in the code). The main idea of the numeric_adaptor scheme though is the to_traits struct, which would cast the library dependent types to Boost's types by using explicit templates(i hope this is the right term). In fact the scheme paves the way for a direct start of the implementation of Bigint since it provided the core design(the very expression template system which was called for) of an optional BigInt library. Making this expression template system exhaustive and make it work with any one of the libraries(GMP ofcourse), must be our priority. @Paul. A. Bristow : I am also following the discussion on Xint, and would comment on it asap. Suggestions and criticism please! -- Problem is a phenomenon indicating lack of thought. Swagat Konchada

1 0

[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.

2 2

[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

1 0

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.

2 1

[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 !

2 2

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.

4 8

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

2 1

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

2 1

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

2 2

[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

3 4

[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

1 0