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filtered graph with bundled properties
by moritz Hilger 03 Aug '06

03 Aug '06

hi, i hava a problem using bundled properties with filtered graph. i've modified the example from the filtered-graph page ( http://www.boost.org/libs/graph/doc/filtered_graph.html) to use edge properties and woul like to create a filter using these bundled properties, but am experiencing problems with the types of the property_map and/or filter. since i'm quite new to c++ and boost i would aprectiate any suggestin, thanks in advance i'm using gcc-3.3.5 and boost-1.34 moritz modified code: struct myEdge { int id; int weight; }; template <typename EdgeWeightMap> struct positive_edge_weight { positive_edge_weight() { } positive_edge_weight(EdgeWeightMap weight) : m_weight(weight) { } template <typename Edge> bool operator()(const Edge& e) const { return 0 < boost::get(m_weight, e); } EdgeWeightMap m_weight; }; int main() { using namespace boost; typedef adjacency_list<vecS, vecS, directedS, //no_property, property<edge_weight_t, int> > Graph; no_property, myEdge > Graph; typedef property_map<Graph, int myEdge::*>::type EdgeWeightMap; typedef graph_traits<Graph>::edge_iterator edge_iter_t; typedef filtered_graph<Graph,positive_edge_weight<EdgeWeightMap> > f_graph_t; typedef graph_traits<Graph>::edge_descriptor Edge; enum { A, B, C, D, E, N }; const char* name = "ABCDE"; Graph g(N); Edge e; bool ins; tie(e,ins)=add_edge(A, B, g); /.../ positive_edge_weight<EdgeWeightMap> filter(get(&myEdge::weight, g)); f_graph_t fg(g, filter); std::cout << "filtered edge set: "; print_edges(fg, name); std::cout << "filtered out-edges:" << std::endl; print_graph(fg, name); return 0; } g++ output: error: no matching function for call to ` boost::bundle_property_map<main()::Graph, boost::detail::edge_desc_impl<boost::directed_tag, size_t>, myEdge, int>:: bundle_property_map()' /homes/combi/Software/Boost/boost/graph/properties.hpp:330: error: candidates are: boost::bundle_property_map<main()::Graph, boost::detail::edge_desc_impl<boost::directed_tag, size_t>, myEdge, int>::bundle_property_map(const boost::bundle_property_map<main()::Graph, boost::detail::edge_desc_impl<boost::directed_tag, size_t>, myEdge, int>&) /homes/combi/Software/Boost/boost/graph/properties.hpp:336: error: boost::bundle_property_map<Graph, Descriptor, Bundle, T>::bundle_property_map(Graph*, T Bundle::*) [with Graph = main()::Graph, Descriptor = boost::detail::edge_desc_impl<boost::directed_tag, size_t>, Bundle = myEdge, T = int] -- /* ICQ 291996214 */ /* MSN moritz.hilger(a)gmail.com */ /* moe1234(a)jabber.ccc.de */ /* del.icio.us/new/moritz.hilger */

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astar-cities.cpp internal compile error
by bringiton bringiton 03 Aug '06

03 Aug '06

Hi, I'm trying to compile the sample from astar-cities.cpp. I however get a INTERNAL COMPILER ERROR. I'm using ms vc++ 6. Can I assume the sample does not run on the old vc++ version? Anything I can do to get around this? Test5.cpp xxx\boost\random\lagged_fibonacci.hpp(81) : fatal error C1001: INTERNAL COMPILER ERROR (compiler file 'msc1.cpp', line 1794) Please choose the Technical Support command on the Visual C++ Help menu, or open the Technical Support help file for more information Generating Code... Error executing cl.exe. Test2.exe - 1 error(s), 1 warning(s)

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[bgl documentation] corrections (?) and improvements to help new users
by David Baird 03 Aug '06

03 Aug '06

Hi! I'm a new user of the BGL. I've attached a couple patches to the BGL documentaion which I think will be very helpful to new users. For example, one of the websites, http://www.boost.org/libs/graph/doc/file_dependency_example.html seems to contain a simple, but confusing (for new users) error: Graph g(N, used_by, used_by + sizeof(used_by) / sizeof(Edge)); In boost-1.33.0, the correct line AFAICT is, Graph g(used_by, used_by + sizeof(used_by) / sizeof(Edge), N); I successfully tested the new instructions in the documentation (which the attached patches apply to) with boost-1.33.0 under Gentoo Linux. If this is the wrong list to post this, please direct me toward the correct place. -David

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[BGL] traversing edges in the graph
by Alejandro Aragón 03 Aug '06

03 Aug '06

Hello, I'm working with undirected graphs and I was wondering if there is an algorithm that traverses all the edges in the graph in such a way that this task is optimized. That is, if you draw a graph with a pencil, the number of times that you should lift the tip of the pencil is minimized. Can anyone give me a hint on this? Thanks, Alex

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[bgl] user defined vertex_descriptor?
by timblech 03 Aug '06

03 Aug '06

hi all, i'm curious, if it's possible to change the type, that a graph uses as vertex_descriptor... i went through the examples, where usually int values are used, which seems to be the default ... for my application, i'd like to use a class pointer as vertex_descriptor, though... the problem i had with property map is, that i was only able to look up a property by vertex_descriptor, but not the other way round... it's possibly only a problem caused by my limited knowledge of the bgl, but it would be very nice, if someone could enlighten me. thanks in advance ... tim -- View this message in context: http://www.nabble.com/-bgl--user-defined-vertex_descriptor--tf2008709.html#… Sent from the Boost - Users forum at Nabble.com.

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help building shared library for lib/filesystem on RHEL4 with gcc 3.4.4
by William Deegan 03 Aug '06

03 Aug '06

Greetings, When I do the following: pushd libs/filesystem/build bjam "-sTOOLS=gcc" I only end up with the /boost-1.30.2/libs/filesystem/build/bin/libboost_filesystem.a/gcc/release/runtime-link-dynamic/libboost_filesystem.a Built and no .so What am I missing? Thanks, Bill

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[test] how to use register_exception_translator with auto_test?
by Jörg Becker 03 Aug '06

03 Aug '06

How can I use the the register_exception_translater with the Auto unit test framework? With boost 1.31 / VC7.1 I wrote a dummy test only containing the register_exception_translator call. This works fine, but with boost 1.33 / gcc3.3 this workaround does not work. Any Suggestions? Jörg

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checking validity
by Ovanes Markarian 03 Aug '06

03 Aug '06

Hello all, I have one specific question. Which I am uncertain if it can be solved anyway. Imagine the following class structure: struct A { some_field* x; }; struct B { optional<A> a_; }; struct C { optional<B> b_; }; Now I have an instance of struct C and would like to know if x is a valid pointer. this code is really ugly: if(c.b_) if(c.b_.a_) if(c.b_.a_.x) //do smth ... This will be really unpleasent if the structure is more deep then this one. Which is the case in our project. The intention would be to write everything in one if-statement. It is not possible to implement a bool or ! operator in these structures, since these are not the only fields and these operators would not know which field should be checked... Currently I am thinking about boost parameter library, but still uncertain if this problem can be solved using it... Can some of you make a suggestion what is the best suitable way of resolving this issue and if this issue resolvable anyway. With Kind Regards, Ovanes Markarian

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Re: [Boost-users] checking validity
by james.jones＠firstinvestors.com 03 Aug '06

03 Aug '06

From: "Ovanes Markarian" <om_boost(a)keywallet.com> > Now I have an instance of struct C and would like to know if x is a valid pointer. > this code is really ugly: > if(c.b_) > if(c.b_.a_) > if(c.b_.a_.x) > //do smth ... > The intention would be to write everything in one if-statement. It is not possible > to implement a bool or ! operator in these structures, since these are not the > only fields and these operators would not know which field should be checked... How about just: if(c.b_ && c.b_.a_ && c.b_.a_.x) //do smth ... Is that cheating? You can do it all in one 'if' statement this way. I suppose you could write a macro to do something like this: #define CHECK(x,y,z,w) (x.y && x.y.z && x.y.z.w) and then use it like this: if(CHECK(c, b_, a_, x)) //do smth ... And maybe you could write the macro in such a way as to take arbitrary lists of arguments. But that's the best I can come up with. - James Jones Administrative Data Mgmt. Webmaster 375 Raritan Center Pkwy, Suite A Data Architect Edison, NJ 08837

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[preprocessor] Enumerating sequence of pairs
by Roman Perepelitsa 03 Aug '06

03 Aug '06

Hello. I want to enumerate sequence of pairs but can't figure out how to do it using boost.preprocessor. Here is example. // sequence of pairs #define SEQ (a, b) (c, d) // How can I implement this macro? #define MAGIC(S) ... MAGIC(SEQ) expands to abcd. If I had possibility to convert SEQ to ((a, b)) ((c, d)) problem would be solved easily because it's standard sequence and thus can be enumerated using with BOOST_PP_SEQ_FOLD_LEFT or another boost.preprocessor algorithm. I have implemented macro which converts SEQ to ((a, b)) ((c, d)) but implementation is huge (I copy-pasted a lot of code from boost.preprocessor). Now I need to enumerate sequence of triples and I don't want to copy-paste again. Any tips? Roman Perepelitsa.

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