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[graph] property_map from bundled properties in a subgraph, how?
by Christian Rössel 28 Nov '08

28 Nov '08

Hi, thanks for the great graph library! My first attempts with boost.graph were quite successful, but now I'm stuck. My question is: How can I get a property_map from bundled properties in a subgraph? (boost 1.34.1, g++ and VC8) In the beginning I had a bidirectional graph with bundled properties and I used a property map from the edge's bundled properties: #include <boost/graph/adjacency_list.hpp> #include <boost/graph/subgraph.hpp> using namespace boost; struct VertexProperty { // ... }; struct EdgeProperty { double length_; // ... }; typedef adjacency_list<vecS, vecS, bidirectionalS, VertexProperty, EdgeProperty> Graph; int main () { Graph g; typedef property_map<Graph, double EdgeProperty::*>::type EdgeWeightMap; EdgeWeightMap ewm = get (&EdgeProperty::length_, g); // use ewm in an algorithm ... return 0; } Everthing worked fine. Then, I had to change the graph-type from adjacency_list to subgraph ... typedef subgraph< adjacency_list<vecS, vecS, bidirectionalS, property<vertex_index_t, int, VertexProperty>, property<edge_index_t, int, EdgeProperty> > > Subgraph; int main () { Subgraph g; typedef property_map<Subgraph, double EdgeProperty::*>::type EdgeWeightMap; EdgeWeightMap ewm = get (&EdgeProperty::length_, g); // use ewm in an algorithm ... return 0; } ... and got this compile error: In instantiation of `boost::property_map<Subgraph, double EdgeProperty::*>': subgraph_property_map.cpp:45: instantiated from here ../../vendor/boost_1_34_1-multithread/boost/graph/properties.hpp:355: error: no type named `vertex_bundled' in `class Subgraph' ../../vendor/boost_1_34_1-multithread/boost/graph/properties.hpp:356: error: no type named `edge_bundled' in `class Subgraph' ../../vendor/boost_1_34_1-multithread/boost/graph/properties.hpp:360: error: no type named `vertex_bundled' in `class Subgraph' ../../vendor/boost_1_34_1-multithread/boost/graph/properties.hpp:360: error: `value' is not a member of `<declaration error>' ../../vendor/boost_1_34_1-multithread/boost/graph/properties.hpp:364: error: no type named `vertex_bundled' in `class Subgraph' ../../vendor/boost_1_34_1-multithread/boost/graph/properties.hpp:364: error: `value' is not a member of `<declaration error>' ../../vendor/boost_1_34_1-multithread/boost/graph/properties.hpp:367: error: no type named `vertex_bundled' in `class Subgraph' ../../vendor/boost_1_34_1-multithread/boost/graph/properties.hpp:367: error: `value' is not a member of `<declaration error>' ../../vendor/boost_1_34_1-multithread/boost/graph/properties.hpp:369: error: no type named `vertex_bundled' in `class Subgraph' ../../vendor/boost_1_34_1-multithread/boost/graph/properties.hpp:369: error: `value' is not a member of `<declaration error>' Is there a way to use property maps from bundled properties in a subgraph? If not, can you give me a hint for a workaround, please. Thanks and best regards, Christian __

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Problem with MSVS 2008 with gregorian
by Dan Smithers 28 Nov '08

28 Nov '08

Hi I have a problem building under studio 2008. It appears that #define max(a,b) ... collides with the member function greg_month::max() and won't compile complaining that not enough arguments are provided. I have stripped the code down test.cpp #include <windows.h> //#undef max #include "boost/date_time/gregorian/gregorian.hpp" void foo() { boost::gregorian::greg_month::max(); } If I put #undef max before including gregorian.h then it compiles. Without I get the errors warning C4003: not enough actual parameters for macro 'max' error C2589: '(' illegal token on right side of '::' error C2143: syntax error : missing ';' before '::' Has anyone seen this before? Is there a workaround? I have tried this with boost 1.37.0 and it still causes problems. thanks dan

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[boost::iostreams] How to get number of bytes written?
by Milan Svoboda 28 Nov '08

28 Nov '08

Hi All, I'm using boost::iostreams and its filters to compress and decompress data. However I'm not able to retrieve number of bytes really written (number of bytes after a compression). Does anybody know how to do that? I'm currently using following code: coffset if offset to where start with writing of compressed data and after call it shall contain the length of the file. This works good to get length of the compressed block unless block of data is written somewhere in the middle of the file thus end of file is not the same as the last offset where compressed data has been written to. io::file_descriptor file(fd); file.seek(coffset, ios_base::beg); { io::filtering_ostream out; // Push the compression filter (bl->type.push(out);) out.push(file); io::write(out, buf, length); // Destroying the object 'out' causes all filters to // flush. } // Update raw length of the file. // coffset = file.seek(0, ios_base::end); Thank you for any help, Milan Svoboda

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Re: [Boost-users] [boost::iostreams] How to get number of bytes written?
by Milan Svoboda 28 Nov '08

28 Nov '08

eg wrote: > Milan Svoboda wrote: >> Hi All, >> >> I'm using boost::iostreams and its filters to compress and decompress >> data. However I'm not able to retrieve number of bytes really written >> (number of bytes after a compression). >> >> Does anybody know how to do that? >> >> I'm currently using following code: >> >> coffset if offset to where start with writing of compressed data and >> after call it shall contain the length of the file. This works good to >> get length of the compressed block unless block of data is written >> somewhere in the middle of the file thus end of file is not the same as >> the last offset where compressed data has been written to. >> >> io::file_descriptor file(fd); >> file.seek(coffset, ios_base::beg); >> { >> io::filtering_ostream out; >> // Push the compression filter (bl->type.push(out);) >> out.push(file); >> >> io::write(out, buf, length); >> >> // Destroying the object 'out' causes all filters to >> // flush. >> } >> // Update raw length of the file. >> // >> coffset = file.seek(0, ios_base::end); >> > > Maybe I dont quite understand the problem... I need to know number of bytes after compression. boost::iostreams::write returns number of bytes that has been passed to filter but there is no direct way to get number of bytes that filter returned... > Could you just write a simple pass-through filter which counts the bytes > only? Something like: > > io::filtering_ostream out; > out.push(compressor()); > out.push(passthru()); // <- this just counts bytes > out.push(file_sink("my_file.txt")); Great! This looks like a right way. Thank you! Milan

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boost and std::wstring
by Sean Farrow 28 Nov '08

28 Nov '08

Hi: Does boost work with std::wstring? Also is there a way to tell c++ to use std::wstring when instanciating an std::string? Cheers Sean.

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Turn off the Header
by Dinesh Kumar R 27 Nov '08

27 Nov '08

Hi Guyz, > *Can you please tell me how to turn off the following in Boost > Serailization? I dont need the following in my document.* > <!DOCTYPE boost_serialization> > <boost_serialization signature="serialization::archive" version="3"> > > *How do I Serialize an array of Object?* > > eg: > class simulated_defects > { > friend class boost::serialization::access; > // friend std::ostream & operator<<(std::ostream &os, const > simulated_defects &gp); > > public: > int defect_num[10]; > int defect_pos; > int defect_area; > float defect_type; > > template<class Archive> > void serialize(Archive & ar, const unsigned int /* file_version */){ > ar & BOOST_SERIALIZATION_NVP(defect_num) > & BOOST_SERIALIZATION_NVP(defect_pos) > & BOOST_SERIALIZATION_NVP(defect_area) > & BOOST_SERIALIZATION_NVP(defect_type); > } > }; > > simulated_defects object[10]; to serialize array of object , I need a > wrapper to define this object inside a class and then serailize, is there > any straight forward method? If i use loop to serialize the Headers at the > top of xml file is inserted at start of each loop? > > Can u please help me? > > > Herzliche Grüße, > Dinesh Kumar > Allmandring 18 A 06 > 70569 Stuttgart > Mobile:+4917682140240 >

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[Math] Accuracy test failures on QNX 6.4.0
by Niklas Angare 27 Nov '08

27 Nov '08

Some of the accuracy tests fail on QNX 6.4.0 x86 with GCC 4.2.4 and Dinkumware 5. Some tests such as test_carlson have a peak error 10%-40% higher than expected while for example test_ellint_1 has huge errors. I'm not sure how to proceed. I'd appreciate of someone could take a look at the trunk regression test results (runner NA-QNX640-qcc). -- Regards Niklas Angare

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Trouble with asio using lib pion and boost.function
by Stephan Menzel 27 Nov '08

27 Nov '08

Hi there, I'm not actually sure this is a boost problem but I'll give it a try and ask for your opinion. Boost version is 1.36 I have a daemon here realising a web interface using pion and asio. Pion is also using asio. On Linux everything runs fine and I have my web interface, but using the same code on windows / vs 2005 I get the weirdest errors such as " Unhandled exception at 0x1004e55d in myapp.exe: 0xC0000005: Access violation reading location 0xcdcdcdd1." The debugger tells me this happens in function_template.hpp: #if !BOOST_WORKAROUND(BOOST_MSVC, < 1300) template<typename R BOOST_FUNCTION_COMMA BOOST_FUNCTION_TEMPLATE_PARMS> typename BOOST_FUNCTION_FUNCTION< R BOOST_FUNCTION_COMMA BOOST_FUNCTION_TEMPLATE_ARGS>::result_type BOOST_FUNCTION_FUNCTION<R BOOST_FUNCTION_COMMA BOOST_FUNCTION_TEMPLATE_ARGS> ::operator()(BOOST_FUNCTION_PARMS) const { if (this->empty()) boost::throw_exception(bad_function_call()); return static_cast<vtable_type*>(vtable)->invoker (this->functor BOOST_FUNCTION_COMMA BOOST_FUNCTION_ARGS); } #endif It says the static_cast rises the exception (?!) Damn MS. Anyway, I debugged into it and the last thing the debugger stepped into was in asio: size_t run(boost::system::error_code& ec) { if (::InterlockedExchangeAdd(&outstanding_work_, 0) == 0) { ec = boost::system::error_code(); return 0; } call_stack<win_iocp_io_service>::context ctx(this); size_t n = 0; while (do_one(true, ec)) if (n != (std::numeric_limits<size_t>::max)()) ++n; return n; } I don't know which line though. Can anyone help shed some light on this? Thanks and greetings... Stephan

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[dataflow]Component Library
by Duane McKinney 27 Nov '08

27 Nov '08

Is there already or are there plans for components to be shared. I know this is a little outside the scope, but it does seem to be closely related. For example if I need an RGB to YUV component, it is likely that it already exists, and if not, it is likely that someone will need it after me.

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How to make custom property map compatible with bgl_named_params?
by Tim Keitt 26 Nov '08

26 Nov '08

I have a custom (internal) property map defined as: struct edge_weight_extractor_map { typedef float8 value_type; typedef float8 reference; typedef WeightedEdgeTableSQLGraph::edge_descriptor key_type; typedef boost::readable_property_map_tag category; }; inline edge_weight_extractor_map::value_type get(const edge_weight_extractor_map& map, const edge_weight_extractor_map::key_type& key) { return key.edge_weight; } The map works fine as an internal property map with eg dijkstra_shortest_paths. However, I cannot get it to work when it is used in a bgl_named_params expression like: boost::brandes_betweenness_centrality(g, centrality, boost::weight_map(get(boost::edge_weight, g))); The error looks like: /usr/include/boost/property_map.hpp:25: error: no type named 'key_type' in 'struct boost::bgl_named_params<edge_weight_extractor_map, boost::edge_weight_t, boost::no_property>' /usr/include/boost/property_map.hpp:27: error: no type named 'reference' in 'struct boost::bgl_named_params<edge_weight_extractor_map, boost::edge_weight_t, boost::no_property>' /usr/include/boost/property_map.hpp:28: error: no type named 'category' in 'struct boost::bgl_named_params<edge_weight_extractor_map, boost::edge_weight_t, boost::no_property>' Do I need to specialize a traits template? Can someone post an example of how this works? (I've tried to specialize bgl_named_params itself, but unsuccessfully.) Thanks. THK -- Timothy H. Keitt http://www.keittlab.org/

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