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Minor bug in docu of lambda library
by Peter Klotz 13 Mar '03

13 Mar '03

URL: http://www.boost.org/libs/lambda/doc/ar01s03.html#id2741989 The code fragment template <class T> : public binary_function<T, T, T> struct plus { should read template <class T> struct plus : public binary_function<T, T, T> { Best regards, Peter.

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slightly off-topic: recommendation for algorithm timing?
by Alejandro Escalante Medina 13 Mar '03

13 Mar '03

This is may a little out of the topic, but maybe you could recommend me some good class for measuring code execution times... Thanks, Alex _________________________________________________________ Do You Yahoo!? La mejor conexión a internet y 25MB extra a tu correo por $100 al mes. http://net.yahoo.com.mx

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Blind dynamic cast
by lorydido 13 Mar '03

13 Mar '03

Good morning, First of all, thank you very much for your help in advance. I have a problem in dynamic casting. sc_object *o = (sc_object*)(x[i]); if (typeid(*o)==typeid(sc_out<bool>)) sc_out<bool> *thisPort=dynamic_cast<sc_out<bool> *>(o); sc_out<T> type is a polymorphic template class that inherits sc_object class. I would like to cast the polymorphic object (*o) without to know the template type T of sc_out<T>. I would avoid all the possible casts that can result in an enormous computational burden. I would like to access to the methods of sc_out<T> type.I cannot modify the code of sc_out<T> and sc_object.Does exist any way to perform this "blind" operation? Does exist a boost library that allows the use of the string typeid.name() as type in dynamic cast operation? thank you very much in advance Lorenzo PIERALISI

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compose_f_gx problem
by pirx 13 Mar '03

13 Mar '03

hi, I've got a question regarding the compose_f_gx function object. I tried to use it in combination with this small example. class Element { public: explicit Element(int nVal) : m_nValue(nVal) {} const int getValue() const { return m_nValue; } private: int m_nValue; }; Element el(3); // a == true; bool a = bind<bool>(equal_to<int>(), _1, 3)(3); // b == 3; int b = mem_fn(&Element::getValue)(el); // c == true bool c = bind<bool>(equal_to<int>(), _1, 3) (mem_fn(&Element::getValue)(el)); // d should also be true, but does not compile bool d = compose_f_gx(bind<bool>(equal_to<int>(), _1, 3), mem_fn(&Element::getValue))(el); The last line does not compile. I don't know why. So what's wrong? thanks, andreas

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Re: [Boost-Users] slightly off-topic: recommendation for algorithm timing?
by Paul Grenyer 13 Mar '03

13 Mar '03

Hi > This is may a little out of the topic, but maybe you > could recommend me some good class for measuring code > execution times... Would boost's timer do what you want? Regards Paul Paul Grenyer Email: pjgrenyer(a)iee.org Web: www.paulgrenyer.co.uk "So long and thanks for all the fish."

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filling in vertex_name_t property for adjacency_list
by Jack Rabbit 13 Mar '03

13 Mar '03

Hi, I'm trying to create a graph that has a name for each vertex. Below is what I've come up with so far. I really don't know what's wrong with it. Can any of you help me out? I'm using boost 1.29.0 with Visual Studio6.0sp5 on win2k. I'm getting some errors on the line that's supposed to get the property map. Then a whole bunch of others because in the end 'name' has the wrong type. kind regards, Dieter Vrancken // create some vertex names typedef std::set<std::string> StringSet; StringSet v_names; std::string names[] = { "v1", "v2", "v3" }; v_names.insert(names, names + sizeof(names)/sizeof(names[0])); // declare the graph typedef boost::adjacency_list<boost::setS, boost::vecS, boost::directedS, boost::vertex_name_t, boost::no_property, boost::graph_name_t, boost::setS> Graph; Graph g(v_names.size()); // get the property map for the vertex names boost::property_map<Graph, boost::vertex_name_t>::type name = boost::get(boost::vertex_name, g); // fill in the names StringSet::const_iterator ss_it = v_names.begin(), ss_end = v_names.end(); int i = 0; for(; ss_it!=ss_end; ++ss_it, ++i) boost::put(name, i, *ss_it);

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Efficient implementation of associative_property_map
by Martin Okrslar 12 Mar '03

12 Mar '03

Dear Boost users, for an application in computational biology I am intendig to use the BGL to compute strongly connected components of a graph with about 600.000 nodes. In the BGL book on page 103 it is mentioned, that "The choice to use std::map to implement the property map is rather inefficient in this case...". Since my graph is large I'm a bit worried about this statement. Could anybody of you please give me a hint, what other datastructure I might use here, to make it efficient? all the best Martin -- ----------------------------------------------------------------------------- Martin Okrslar MPI for Molecular Genetics phone: ++ 49 + 30 / 8413-1166 Computational Molecular Biology Fax: ++ 49 + 30 / 8413-1152 Ihnestrasse 73 email: okrslar(a)molgen.mpg.de D-14195 Berlin URL: http://cmb.molgen.mpg.de -----------------------------------------------------------------------------

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adjacency_matrix
by agiatojon 12 Mar '03

12 Mar '03

Hello all, I'm new to the list and to Boost in general and am trying to use an adjacency_matrix in order to plot coordinates (hopefully that is a good use for it). I just started trying to learn it and have entered the sample program from page 237 into my compiler (VS.NET) Below is the program I have entered. I am getting errors in that print_vertices, print_edges, and print_graph are undefined and are not members of boost. Any help apprechiated! Thanks. /** * adjaMatri.cpp * Nov 7th, 2002 * Boost Graph Library, pg. 237 */ #include <iostream> using std::cout; using std::cin; using std::endl; #include <boost/graph/adjacency_matrix.hpp> using namespace boost; int main() { enum { A, B, C, D, E, F, N }; const char *name = "ABCDEF"; typedef boost::adjacency_matrix<boost::undirectedS> UGraph; UGraph ug(N); add_edge(B, C, ug); add_edge(B, F, ug); add_edge(C, A, ug); add_edge(D, E, ug); add_edge(F, A, ug); cout << "vertex set: "; boost::print_vertices(ug, name); cout << endl; cout << "edge_set: "; boost::print_edges(ug, name); cout << endl; cout << "incident edges: "; boost::print_graph(ug, name); cout << endl; cout << "Press enter to exit..."; cin.get(); return EXIT_SUCCESS; } Jon Agiato JonAgiato(a)nyc.rr.com

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BGL: getting components of graphs with properties
by Martin Okrslar 12 Mar '03

12 Mar '03

Dear Group, when computing the connected components of a BGL graph one has to create a vector that holds the component integer assigned to each vertex (See http://www.boost.org/libs/graph/example/connected_components.cpp and http://www.boost.org/libs/graph/doc/connected_components.html) OK, that works very well. But how can I get the component number of each vertex? If my graph has internal properties, I can not simply access the vector with an iterator on the graph vertices: component[*vi]; //doesn't work! This doesn't work, because the vertices (to be specific: the vertex desriptors) of the graph aren't integers if the graph has internal properties. Any idea how to get the component of each vertex? all the best Martin -- ----------------------------------------------------------------------------- Martin Okrslar MPI for Molecular Genetics phone: ++ 49 + 30 / 8413-1166 Computational Molecular Biology Fax: ++ 49 + 30 / 8413-1152 Ihnestrasse 73 email: okrslar(a)molgen.mpg.de D-14195 Berlin URL: http://cmb.molgen.mpg.de -----------------------------------------------------------------------------

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[V2] Problems with stage rule
by klapshin 12 Mar '03

12 Mar '03

Hi, I am having few problems on CygWin with latest boost CVS snapshot. I am building project with a number of dlls, and I need a way to run program easily. I tried hardcode-dll-paths=true, but it does not seem to work on CygWin, so I decided to use stage rule to copy all binaries in top/bin folder. First problem was that CP variable is empty and copying of the dlls failed. I worked around this one with bjam -sCP=cp. BTW, was not it supposed to be relinked rather then copied? Next problem was with exe file. Stage failed with following errors: ----------------- /cygdrive/c/work/boost1/tools/build/new/stage.jam:97: in object(stage-exe-gener tor)(a)1.run *** argument error * rule object(file-target)(a)174.depends ( d + ) * called with: ( ) * missing argument d /cygdrive/c/work/boost1/tools/build/new/virtual-target.jam:86:see definition of rule 'object(file-target)(a)174.depends' being called /cygdrive/c/work/boost1/tools/build/new/generators.jam:638: in try-one-generato /cygdrive/c/work/boost1/tools/build/new/generators.jam:885: in construct-withou -caching /cygdrive/c/work/boost1/tools/build/new/generators.jam:937: in generators.const uct /cygdrive/c/work/boost1/tools/build/new/stage.jam:56: in construct /cygdrive/c/work/boost1/tools/build/new/targets.jam:604: in object(stage-target class)(a)3.generate /cygdrive/c/work/boost1/tools/build/new/targets.jam:386: in generate-really /cygdrive/c/work/boost1/tools/build/new/targets.jam:363: in object(main-target) 3.generate /cygdrive/c/work/boost1/tools/build/new/targets.jam:182: in object(project-targ t)(a)1.generate /cygdrive/c/work/boost1/tools/build/new/build-system.jam:140: in load /cygdrive/c/work/boost1/tools/build/new/modules.jam:171: in import /cygdrive/c/work/boost1/tools/build/new/bootstrap.jam:41: in boost-build /cygdrive/c/work/pricing/boost-build.jam:13: in module scope ------------------ One more thing. Suppose I want to install all dlls to bin subfolder of project root. I tried to define path-constant in project-root, and then in one of subprojects apply stage on target and supply path from that path-constant. I end up with dll being copied into bin subfolder of subproject, rather then root. Is it expected behavior? My workaround was to put all stage rules in root Jamfile. - Kirill

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