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[Graph] redefinition of hash<void*> clashes with boost/functional/hash.hpp
by Ioannis Papadopoulos 27 Oct '11

27 Oct '11

Hi, In graph/detail/adjacency_list.hpp:2766 there is a specialization of struct hash for void*. Isn't the generic pointer specialization in functional/hash/extensions.hpp:172 enough? The problem I am facing is the following (which I couldn't reproduce in a trivial example): 1. I include <boost/functional/hash.hpp> and <boost/tr1/unordered_map.hpp> 2. I create an std::tr1::unordered_map<void*, int> and typedef std::tr1::unordered_map<void*, int>::iterator iterator_type; 3. In some test file that includes <boost/graph/adjacency_list.hpp> and uses it, I get the following error (gcc 4.4.5/4.6.1): /usr/local/include/boost/graph/detail/adjacency_list.hpp:2766: error: specialization of ‘boost::hash<void*>’ after instantiation /usr/local/include/boost/graph/detail/adjacency_list.hpp:2766: error: redefinition of ‘struct boost::hash<void*>’ /usr/local/usr/include/boost/functional/hash/extensions.hpp:172: error: previous definition of ‘struct boost::hash<void*>’ I can resolve it by providing my own hash functor to the unordered_map (which causes hash<void*> not to be instantiated). I will keep trying to provide a trivial example. Thanks

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[graph] Graph type needed in Graph Proptery, cyclic definition problem
by Christoph 26 Oct '11

26 Oct '11

Hi List, id like to use a std::priority_queue as a property of my graph. In the priority queue i store some vertices by the vertex degree. I have to Problems i think: First i have to define the priority_queue in a struct graph_properties. Within this priority_queue definition i use a comparison object as the 3rd template parameter. Now the problem is, that the class vertex_degree_compare needs to know the graph type, because of the use of out_degree(u, g) but the graph type depends on the graph_struct and this depends on the priority_queue definition. For the edge descriptors and vertex descriptors i used the traits_class http://www.boost.org/doc/libs/1_47_0/libs/graph/doc/adjacency_list_traits.h… but for the graph itself i don't know how to proceed. Any help is highly appreciated. // begin code #include <iostream> #include <queue> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/graph_utility.hpp> typedef boost::adjacency_list_traits<boost::listS, boost::vecS, boost::bidirectionalS> link_adjacency_list_traits; struct vertex_properties { vertex_properties () : color (-1) {} unsigned int vertex_index; unsigned int vertex_index_t; int color; std::list <int> free_colors; std::map <int, link_adjacency_list_traits::edge_descriptor > used_colors; }; struct edge_properties { edge_properties () : color (-1) {} int color; }; struct graph_properties { int delta; std::priority_queue < link_adjacency_list_traits::vertex_descriptor, vertex_degree_compare> A; std::priority_queue < link_adjacency_list_traits::vertex_descriptor, vertex_degree_compare> B; }; typedef boost::adjacency_list < boost::listS, boost::listS, boost::bidirectionalS, vertex_properties, edge_properties, graph_properties> link_graph; typedef boost::graph_traits <link_graph> lgt; class vertex_degree_compare { private: link_graph g; public: vertex_degree_compare (const link_graph &g) : g(g) {} bool operator() (link_adjacency_list_traits::vertex_descriptor& u, link_adjacency_list_traits::vertex_descriptor& v) const { return out_degree (u, g) < out_degree (v, g); } }; int main(int argc, char** argv) { return 0; } // end code best regards Christoph

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Accessing the edge through edge descriptor with bundled properties
by giridhar 26 Oct '11

26 Oct '11

Hello All, I have to access an edge in a vector called border_edge through an edge descriptor. For example for( vector<Edge>::iterator j=border_edge.begin();j!=border_edge.end();++j) { Edge e = t1[*j]; // I am getting error saying that No suitable conversion for Edge to Edgep exits } *Details*: border_edge is of type std::vector<Edge> border_edge(10); Graph as: typedef subgraph< adjacency_list<vecS, vecS, undirectedS, Vertexp, property< edge_index_t, unsigned int, Edgep > > > Graph; typedef Graph::edge_descriptor Edge; I have exterior Edge property defined as struct Edgep { int edge_index; int edge_w; std::string edge_name; int capacity; int residual_capcity; int bandwidth_used; }; Whenever I am adding edges into graph I am updating this border_edge vector. Say I am adding an edge from vertex 0 to 4 then I am doing this border_edge[i] = (add_edge(0,4,t)).first; //i is an example index. It is actually running in the loop. Can anyone please give some suggestions regarding this. How to access this edge which is inside vector? or what descriptor type should I use? -- Regards, Giridhar

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[graph] VertexList type boost::vecS and boost::listS
by Christoph 26 Oct '11

26 Oct '11

Hi, I have some Questions concerning the Boost Graph Library graph template selector VertexList type. In the docs at http://www.boost.org/doc/libs/1_47_0/libs/graph/doc/using_adjacency_list.ht… I just found the two types documented. 1. How do i use the printed_graph (...) with a graph type that uses boost::listS instead of boost::vecS? I read that by using boost::vecS there is automatically an internal property for each Vertex created, which is the index of the vertex. I assume this is the reason why 'add_edge (1,2,g);' and 'print_graph (g,get(boost::vertex_index, g));' work for a graph g with a boost::vecS VertexList. However i cannot simply do 'add_edge (1,2,g);' or 'print_graph (g,get(boost::vertex_index, g));' vor a graph g with a VertexList type listS. How do i specify a vertex_index property for VertexList listS graph type, so that i can somehow use print_graph (g,something);? How are vertices internally identified when using listS? Are there any documentations about the function 'vertex()'? I think it is missing in Table 1: Summary of boost graph concepts in http://www.boost.org/doc/libs/1_47_0/libs/graph/doc/graph_concepts.html Look at the difference in using add_edge for the two different graph types and what happens if i try to insert an edge with one vertex not yet being part of the vertex set. Here is an example: //begin code #include <iostream> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/graph_utility.hpp> typedef boost::adjacency_list < boost::listS, boost::vecS, boost::bidirectionalS> link_graph_vertex_vec; typedef boost::adjacency_list < boost::listS, boost::listS, boost::bidirectionalS> link_graph_vertex_list; int main(int argc, char** argv) { link_graph_vertex_vec g1(3); std::cout << "Number of vertices in g1: " << num_vertices (g1) << std::endl; add_edge (0,1,g1); std::cout << "Number of vertices in g1: " << num_vertices (g1) << std::endl; add_edge (1,2,g1); std::cout << "Number of vertices in g1: " << num_vertices (g1) << std::endl; add_edge (2,10,g1); std::cout << "Number of vertices in g1: " << num_vertices (g1) << std::endl; print_graph (g1, get(boost::vertex_index, g1)); link_graph_vertex_list g2(3); std::cout << "Number of vertices in g2: " << num_vertices (g2) << std::endl; add_edge (vertex(0,g2), vertex(1,g2), g2);//add_edge (0,1,g2); std::cout << "Number of vertices in g2: " << num_vertices (g2) << std::endl; add_edge (vertex(1,g2), vertex(2,g2), g2);//add_edge (1,2,g2); std::cout << "Number of vertices in g2: " << num_vertices (g2) << std::endl; //add_edge (vertex(2,g2), vertex(3,g2), g2);//add_edge (2,3,g2); //vertex(3,g2) // what is the return type, why does the program exit? std::cout << "Number of vertices in g2: " << num_vertices (g2) << std::endl; return 0; } //end code I have to decide whether to use boost::listS or boost::vecS for the VertexList type. The 'interface' of the vecS type graph operations are much easier for me to understand and to use. But on the other hand the listS type has the faster remove and insert operations. best regards Christoph

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odeint feedback request
by Karsten Ahnert 25 Oct '11

25 Oct '11

Dear community, odeint is a library for solving ordinary differential equations and has been discussed several times on this list. After successfully fulfilling the GSOC 2011 we continued working on odeint and we published two papers which are available at the arxiv: http://arxiv.org/abs/1110.3397 http://arxiv.org/abs/1110.3233 We would like to request feedback and/or comments on the implementation and the current status of odeint. The library and the documentation are available at the github: https://github.com/headmyshoulder/odeint-v2 http://headmyshoulder.github.com/odeint-v2/doc/index.html Thank you, Mario and Karsten

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[regex] /g
by Andrey Moshbear 25 Oct '11

25 Oct '11

I have a few questions regarding implementing /g when using boost.regex. Firstly, is the iterator-pair form of match equivalent to /g? I.e. { sregex_iterator m1(str.begin(), str.end(), regex); sregex_iterator m2; for (; m1 != m2; ++m1) { // do something with *m1 } } Secondly, does regex_replace() loop internally in a /g fashion? 001100 Andrey "m05hbear" Vul 010010 011110 andrey at moshbear dot net 100001 andrey dot vul at gmail 101101 110011

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[fusion] push_back / pop_back
by Daniel Bradburn 25 Oct '11

25 Oct '11

Hi, I am trying to do the following: #include <string>#include <boost/fusion/tuple.hpp>#include <boost/fusion/include/push_back.hpp>#include <boost/fusion/include/pop_back.hpp> int main(int argc, char* argv[]) { typedef boost::fusion::tuple<int> T1; typedef boost::fusion::result_of::push_back<const T1, std::string>::type T2; T1 a(0); T2 b(boost::fusion::push_back(a, std::string(""))); boost::fusion::get<0>(); T1 c(boost::fusion::pop_back(b)); return 0; } However I get the following compilation errors: error C4430: missing type specifier - int assumed. Note: C++ does not support default-int error C2868: 'boost::lazy_disable_if_c<B,T>::type' : illegal syntax for using-declaration; expected qualified-name error C2602: 'boost::lazy_disable_if_c<B,T>::type' is not a member of a base class of 'boost::lazy_disable_if_c<B,T>' error C2504: 'boost::fusion::extension::at_impl<Tag>::apply<Sequence,N>' : base class undefined error C2504: 'boost::fusion::extension::at_impl<Tag>::apply<Sequence,N>' : base class undefined error C2146: syntax error : missing ';' before identifier 'type' error C2039: 'type' : is not a member of 'boost::fusion::result_of::at_c<Sequence,N>' error C2664: 'boost::fusion::tuple<T0>::tuple(const boost::fusion::tuple<T0> &)' : cannot convert parameter 1 from 'boost::fusion::iterator_range' to 'const boost::fusion::tuple<T0> &' error C2146: syntax error : missing ',' before identifier 'type' error C2065: 'type' : undeclared identifier error C2039: 'type' : is not a member of 'boost::fusion::result_of::prior<Iterator>' Having read the topic here : http://lists.boost.org/Archives/boost/2011/08/184624.php it looks like this is partly due to a bug in the pop_back implementation. Is there a fix for this? However I would like to know if it is also possible to use boost::fusion::get on the result of push_back? Best regards Daniel Bradburn

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throw and catch exception
by Christer Borgqvist 25 Oct '11

25 Oct '11

I have a code like this when execute the IdHTTPServDataEMVObj.Exequte(); it will throw a std::runtime_error if running one thread all is fine, the catch is excequted, but if running two threads then the application crash. What is the problem, have i miss something appreciate any help. huvcbo.. void server(boost::asio::io_service& io_service, short port) { tcp::acceptor a(io_service, tcp::endpoint(tcp::v4(), port)); for (;;) { socket_ptr sock(new tcp::socket(io_service)); a.accept(*sock); boost::thread t(boost::bind(socketclientEMVthread, sock, logFunc, mygetFunc, mybackFunc, statusUpdateFunc)); } } the client thread void socketclientEMVthread( socket_ptr sock) { cout << "connect on port " << sock->remote_endpoint().port() << endl; for (;;) { char data[max_length]; boost::system::error_code error; size_t length = sock->read_some(boost::asio::buffer(data), error); if (error == boost::asio::error::eof) break; // Connection closed cleanly by peer. else if (error) throw boost::system::system_error(error); // Some other error. std::string trans_in(data), trans_out; CIdHTTPServDataEMVObj IdHTTPServDataEMVObj(trans_in); try { // this is thrown IdHTTPServDataEMVObj.Exequte(); if ( IdHTTPServDataEMVObj.txBufferlen > 0 && IdHTTPServDataEMVObj.txBufferlen != std::string::npos) { trans_out = IdHTTPServDataEMVObj.txBuffer; } else { trans_out = trans_in; } } catch(trans_error &te) { trans_out = te.what(); boost::asio::write(*sock, boost::asio::buffer(trans_out, trans_out.size())); break; } boost::asio::write(*sock, boost::asio::buffer(trans_out, trans_out.size())); break; } }

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[date time] How to get "10" and not "Oct"
by Ken Murphy 24 Oct '11

24 Oct '11

I have the following code: std::string db_time() { typedef boost::posix_time::ptime TimeT; TimeT ct = boost::posix_time::microsec_clock::local_time(); std::stringstream ss; boost::local_time::local_time_facet* output_facet = new boost::local_time::local_time_facet("%Y-%m-%d %h:%m:%s"); ss.imbue(std::locale(std::locale::classic(), output_facet)); ss << ct; return ss.str(); } Currently, the following string is returned: 2011-Oct-24 12:43:05.476990 How do I get the month as "10" and not as "Oct"? Ken Murphy

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asio. documentation errors.
by niXman 24 Oct '11

24 Oct '11

Hi list! In the documentation for upd::socket::bind(): http://www.boost.org/doc/libs/1_47_0/doc/html/boost_asio/reference/basic_da… examples are shown from the tcp::socket::bind() Thanks. niXman.

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