September 2007 - Boost-users

Graph, Bayesian networks.
by Yann Golanski 27 Sep '07

27 Sep '07

Is there any support for Bayesian networks within the Boost graph library? Any third party library anyone knows about? Thanks. -- yann(a)kierun.org -= H+ =- www.kierun.org PGP: 009D 7287 C4A7 FD4F 1680 06E4 F751 7006 9DE2 6318

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problem with serialization library
by calogero bennici 27 Sep '07

27 Sep '07

Hi all, just to example, I tried to execute the code in the "simple example": // create and open a character archive for output std::ofstream ofs("genetic_parameters.txt"); // create class instance const gps_position g(35, 59, 24.567f); // save data to archive { boost::archive::text_oarchive oa(ofs); // write class instance to archive oa << g; // archive and stream closed when destructors are called } // ... some time later restore the class instance to its orginal state gps_position newg; { // create and open an archive for input std::ifstream ifs("filename", std::ios::binary); boost::archive::text_iarchive ia(ifs); // read class state from archive ia >> newg; // archive and stream closed when destructors are called } but at line oa << g; the program break in Kernell32.dll. Any suggestions? Regards, Calogero _________________________________________________________________ The next generation of MSN Hotmail has arrived - Windows Live Hotmail http://www.newhotmail.co.uk

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Iostreams and Network
by JD 26 Sep '07

26 Sep '07

Hi, Iostreams documentation states: "For example, Boost.Iostreams can be used to create streams to access TCP connections". Is there any such attempt to create a TCP/IP communicating Source/Sink couple? I know asio is doing this, but I was looking for an pure Iostreams solution. Regards, JD

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program_options configuration file - unknown options
by Marty Fried 26 Sep '07

26 Sep '07

I'd like to use program options in my program, but we have one section of data which consists of aliases plus a definition for each alias, neither of which is known to us. The Boost program_options expects that we specify each possible option, and throws an exception for any that are not listed. Is there a good way to have it ignore those options it doesn't know about? It would be OK if we had to use a different parser for the aliases, but changing the format would make it hard to use, I think. Thanks to anyone who can give me a hint as to how to best handle this, if possible. -- Marty Fried Left Coast, USA

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[parameter] requirement const char*
by Jean-Christophe Roux 26 Sep '07

26 Sep '07

Hello, Thank you for the parameter library; it is making my library much nicer to use. Two questions: 1. I am assuming there is no runtime penalty to use the BOOST_PARAMETER version of a function. Is that right? 2. My code looks like that: namespace keywords { BOOST_PARAMETER_NAME(id) BOOST_PARAMETER_NAME(test) } BOOST_PARAMETER_FUNCTION ( (void),foo,keywords::tag, (optional (id, *, "") (test, (const char*), "") ) ) { ... } Here the parameters must be converted, if necessary, to const char* in order to be used later. What would be the best way to write the requirement that the type must be const char* or must be convertible to const char*? thanks for your help

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[boost-users] msvc operator error.
by chun ping wang 26 Sep '07

26 Sep '07

k lets say i have the following snippet of code typedef boost::operators<T> operatorsT; template <class T> void myFunc(const T&) { typedef boost::operators<T> operatorT; BOOST_STATIC_ASSERT((is_base_of<operatorT, T>::value)); // bunch of code after... } on my compiler it generates this error. :/boost_msvc/include\boost/operators.hpp(283) : error C2803: 'operator --' must have at least one formal parameter of class type C:/boost_msvc/include\boost/operators.hpp(268) : see reference to class template instantiation 'boost::decrementable<T,B>' being compiled with [ T=int, B=boost::detail::empty_base<int> ] C:/boost_msvc/include\boost/operators.hpp(284) : error C2146: syntax error : missing ';' before identifier 'nrv' C:/boost_msvc/include\boost/operators.hpp(284) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int C:/boost_msvc/include\boost/operators.hpp(284) : error C2061: syntax error : identifier 'x' C:/boost_msvc/include\boost/operators.hpp(284) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int C:/boost_msvc/include\boost/operators.hpp(284) : fatal error C1903: unable to recover from previous error(s); stopping compilation

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big integer library
by Peng Yu 26 Sep '07

26 Sep '07

Hi, I found some discussion on big integer in boost mailing list. But I couldn't find the library in boost website. Can you let me know where it is? Thanks, Peng

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Problem in cal diameter and girth using BGL
by tonyaim83 26 Sep '07

26 Sep '07

Hi... I want to calculate diameter and girth of a graph using BGL so i m taking http://www.cs.ualberta.ca/~ghali/courses/texts/BGL/html/girth.cpp.html#pred… as a reference. I have already created graph using adjacency_list Now i m not able to understand how to use :- typedef boost::v_property<long> dist_t; boost::property_map<Graph*, dist_t>::type d_map; typedef boost::u_property<vertex_descriptor> pred_t; boost::property_map<Graph*, pred_t>::type p_map; And for what it stands for ... Here i m not using #include <boost/graph/stanford_graph.hpp> Also let me know where it is being defined.. Is there any alternative to calculate diameter and girth -- View this message in context: http://www.nabble.com/Problem-in-cal-diameter-and-girth-using-BGL-tf4486815… Sent from the Boost - Users mailing list archive at Nabble.com.

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Problem in calculating radius and girth of a graph
by abhishek.v＠tcs.com 26 Sep '07

26 Sep '07

Hi I m able to calculate the diameter of a graph using BFS visitor. I got all the distances and then i m finding out the maximum using the following to get the diameter .. template <class Distance>class calc_distance_visitor : public boost::bfs_visitor<> { public: calc_distance_visitor(Distance d,std::size_t& girth) : distance(d),Girth(girth) { } template <class Graph> void tree_edge(typename boost::graph_traits<Graph>::edge_descriptor e,Graph& g) { Vertex u, v; u = boost::source(e, g); v = boost::target(e, g); distance[v] = distance[u] + 1; } }; and then typedef std::vector<size_type> IntVector; /// Create N x N matrix for storing the shortest distances //// between each vertex. Initialize all distances to zero. std::vector<IntVector> d_matrix(num_vertices(g),IntVector(num_vertices(g), 0)); size_type i; std::size_t girth = std::numeric_limits<std::size_t>::max(); for (i = 0; i < num_vertices(g); ++i) { calc_distance_visitor<size_type*> vis(&d_matrix[i][0],girth); Vertex src = vertices(g).first[i]; breadth_first_search(g, src, boost::visitor(vis)); } for (i = 0; i < num_vertices(g); ++i) { diameter = std::max(diameter, *std::max_element(d_matrix[i].begin(), d_matrix[i].end())); } Now what is required is the radius which means minimum distance so i used the following code :- for (i = 0; i < num_vertices(g); ++i) { radius = std::min(radius, *std::min_element(d_matrix[i].begin(), d_matrix[i].end())); } What is wrong with the above code . As i m getting incorrect values in case of radius and i cross checked all values are correct... Secondly i m facing problem in calculating girth of a graph :- For this what is needed is to first identify if cycle exist and then find the maximum distance for calculating circumfrence and minimum distance for calculating girth of a graph.. For identifying the cycles i used the following code. :- struct cycle_detector : public dfs_visitor<> { cycle_detector( bool& has_cycle):_has_cycle(has_cycle) { } template <class Edge, class Graph> void back_edge(Edge, Graph&) { file_op<<"It's inside back_edge "; Vertex u, v; u = boost::source(e, g); // I m not able to understand what vertex values it is giving in this case.. v = boost::target(e, g); _has_cycle = true; } protected: bool& _has_cycle; }; bool has_cycle = false; typedef Traits::vertices_size_type size_type; cycle_detector vis(has_cycle); boost::depth_first_search(g, visitor(vis)); The above code is same as given on http://www.boost.org/libs/graph/doc/file_dependency_example.html Now what i want is to record the vertex on which cycle is present and then calculate the distance. So how should i record the vertex name/Index. Kindly help Thanks Abhishek Vyas Tata Consultancy Services Mailto: abhishek.v(a)tcs.com Website: http://www.tcs.com ____________________________________________ Experience certainty. IT Services Business Solutions Outsourcing ____________________________________________ =====-----=====-----===== Notice: The information contained in this e-mail message and/or attachments to it may contain confidential or privileged information. If you are not the intended recipient, any dissemination, use, review, distribution, printing or copying of the information contained in this e-mail message and/or attachments to it are strictly prohibited. If you have received this communication in error, please notify us by reply e-mail or telephone and immediately and permanently delete the message and any attachments. Thank you

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Unit testing Questions
by Thomas Thorp 25 Sep '07

25 Sep '07

I'm a newbie with boost and have some questions about unit testing- 1 - In looking for documentation, I see that most of the sample links on the boost.org site for unit testing examples are dead. Is there another place I can see them. 2 - Is there a good tutorial on all of the features of boost testing? It looks really good, but it seems to be really hard to follow. 3 - Is there a way to test for 1.#QNAN in a floating point value? This is part of my initialization sequence. "BOOST_CHECK_EQUAL" results a failure. Thanks in advance. Thomas Thorp Senior Software C++ Engineer Advanced Composite Software - Production

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