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Re: [Boost-users] converting value before inserting into a list
by Flex Ferrum 20 Sep '06

20 Sep '06

Hello. David Walthall wrote: > Flex Ferrum wrote: > > map<int,int> m; > > vector<int> a,b; > > std::transform(a.begin(), a.end(), std::back_inserter(b), var(m)[_1]); > Is this a case where transform is not appropriate? My understanding is > that the operation supplied to transform must not have any side effects, > and here m may be modified by operator[]. Does this count as a side effect? Yes, of course, map::operator[] _can_ have side effects. But if author of such code absolutely sure what each value from source vector has corresponded map entry then map::operator[] will not have side effects and will suitable for transormation operation. ____________ Best Regards Flex

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Boost.Python, MinGW, & ImportError
by Corey Wright 20 Sep '06

20 Sep '06

this is in reference to the following postings to c++-sig and boost-users: 1. http://lists.boost.org/boost-users/2006/02/17367.php 2. http://mail.python.org/pipermail/c++-sig/2006-September/011202.html the summary: individuals, including myself, are seeing "ImportError: dynamic module does not define init function (inithello)" whenever trying to import a module compiled with mingw against boost.python, specifically the python examples and tutorial distributed with boost. the symptom: g++ fails to properly link whenever a null library search path (ie -L"") is specified (because maybe it stops parsing arguments there?). the cause: MINGW_BIN_DIRECTORY is null the short answer (for those newbies just trying to get through the tutorial/example and don't care to dive into the details of boost.build): bjam -sMINGW_BIN_DIRECTORY=C:\MinGW\bin (or where ever your mingw installation is) the longer answer: see attached patch the explanation: A. in gcc-tools.jam: 1. the gcc-Link-action contains -L"$(STDLIBPATH:T)" 2. STDLIBPATH is set based on following commands: a. flags gcc GCC_STDLIB_DIRECTORY : $(GCC_STDLIB_DIRECTORY) ; b. GCC_STDLIB_DIRECTORY ?= $(GCC_ROOT_DIRECTORY)$(SLASH)lib ; c. flags gcc STDLIBPATH : $(GCC_STDLIB_DIRECTORY) ; but when using mingw, the values in gcc-tools.jam are set... B. in mingw-tools.jam 1. local GCC_BIN_DIRECTORY = $(MINGW_BIN_DIRECTORY) ; 2. local GCC_STDLIB_DIRECTORY = $(MINGW_STDLIB_DIRECTORY) ; 3. flags mingw STDLIBPATH : $(GCC_BIN_DIRECTORY) ; so for mingw, STDLIBPATH is always composed of GCC_BIN_DIRECTORY (which is really MINGW_BIN_DIRECTORY). if you set MINGW_STDLIB_DIRECTORY, but not MINGW_BIN_DIRECTORY, you end up with -L"mingw_stdlib_directory" -L"". you must set MINGW_BIN_DIRECTORY to get rid of the null string or insure the null string in MINGW_BIN_DIRECTORY never gets added to STDLIBPATH. i successfully compiled boost.python without needing to set MINGW_BIN_DIRECTORY because the mingw tools are in my path and everything "just works". but if you try to compile python extensions (or at least the tutorial and examples), then things start mysteriously failing. i haven't had time to fully test my patch by building all of boost with it applied, but i'm currently in the process and last i looked bjam had compiled date and filesystem libraries, and was working on iostreams. thanks for boost.python and the mingw support (it feels liberating to compile free software, gratis & libre, with free software; and we'll overlook the operating system ;-). -- undefined(a)pobox.com

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boost shmem
by Clarke, Trevor 20 Sep '06

20 Sep '06

I need to use shared memory in an application on Windows and Solaris so I've grabbed boost::shmem 0.93. It works fine on Windows but fails to compile on Solaris 10/SunPro 11. Has anybody had success on Solaris? I get the following errors when I try to compile. "boost/shmem/detail/segment_manager.hpp", line 253: Error: Redefining boost::shmem::detail::segment_manager<boost::shmem::detail::CharType, boost::shmem::detail::MemoryAlgorithm, boost::shmem::detail::IndexType<boost::shmem::detail::IndexConfig>> after use in boost::shmem::detail::segment_manager<char, boost::shmem::simple_seq_fit<boost::shmem::shared_mutex_family, boost::shmem::offset_ptr<void, boost::shmem::offset_1_null_ptr>>, boost::shmem::flat_map_index<boost::shmem::IndexConfig>>::index_config<c har>. "boost/shmem/indexes/flat_map_index.hpp", line 29: Where: While specializing "boost::shmem::detail::segment_manager<char, boost::shmem::simple_seq_fit<boost::shmem::shared_mutex_family, boost::shmem::offset_ptr<void, boost::shmem::offset_1_null_ptr>>, boost::shmem::flat_map_index<boost::shmem::IndexConfig>>::index_config<c har>". "boost/shmem/indexes/flat_map_index.hpp", line 29: Where: Specialized in boost::shmem::flat_map_index_aux<boost::shmem::detail::segment_manager<c har, boost::shmem::simple_seq_fit<boost::shmem::shared_mutex_family, boost::shmem::offset_ptr<void, boost::shmem::offset_1_null_ptr>>, boost::shmem::flat_map_index<boost::shmem::IndexConfig>>::index_config<c har>>. "boost/shmem/indexes/flat_map_index.hpp", line 45: Where: Specialized in boost::shmem::flat_map_index<boost::shmem::detail::segment_manager<char, boost::shmem::simple_seq_fit<boost::shmem::shared_mutex_family, boost::shmem::offset_ptr<void, boost::shmem::offset_1_null_ptr>>, boost::shmem::flat_map_index<boost::shmem::IndexConfig>>::index_config<c har>>. "boost/shmem/detail/segment_manager.hpp", line 1046: Where: Specialized in boost::shmem::detail::segment_manager<char, boost::shmem::simple_seq_fit<boost::shmem::shared_mutex_family, boost::shmem::offset_ptr<void, boost::shmem::offset_1_null_ptr>>, boost::shmem::flat_map_index<boost::shmem::IndexConfig>>::header_t. "boost/shmem/detail/segment_manager.hpp", line 1053: Where: Specialized in boost::shmem::detail::segment_manager<char, boost::shmem::simple_seq_fit<boost::shmem::shared_mutex_family, boost::shmem::offset_ptr<void, boost::shmem::offset_1_null_ptr>>, boost::shmem::flat_map_index<boost::shmem::IndexConfig>>. "boost/shmem/detail/named_object_impl.hpp", line 73: Where: Specialized in boost::shmem::detail::basic_named_object_impl<char, boost::shmem::simple_seq_fit<boost::shmem::shared_mutex_family, boost::shmem::offset_ptr<void, boost::shmem::offset_1_null_ptr>>, boost::shmem::flat_map_index<boost::shmem::IndexConfig>>. "boost/shmem/named_shared_object.hpp", line 42: Where: Specialized in boost::shmem::basic_named_shared_object<char, boost::shmem::simple_seq_fit<boost::shmem::shared_mutex_family, boost::shmem::offset_ptr<void, boost::shmem::offset_1_null_ptr>>, boost::shmem::flat_map_index<boost::shmem::IndexConfig>>. "Signaling.h", line 52: Where: Specialized in non-template code. 1 Error(s) and 1 Warning(s) detected. The offending bit of code is: void sendPathAndName(std::string &path, std::string &name, boost::shmem::named_shared_object *pSegment) { if(mpPath != NULL) { pSegment->deallocate(mpPath.get()); // <-- error } Where mpPath is a boost::shmem::offset_ptr<char> that was created with pSegment->allocate() -------------------- Trevor R.H. Clarke tclarke at ball.com <mailto:tclarke@ball.com> Ball Aerospace & Technologies Corp

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Re: [Boost-users] converting value before inserting into a list
by Flex Ferrum 20 Sep '06

20 Sep '06

Hello, Alexander Shyrokov, You wrote: > I want to convert values according to a map before inserting it into the > list. What is a proper way to do that? > I have this: > map<int,int> m; > vector<int> a,b; > for(vector<int>const_iterator i=a.begin();i!=a.end();++i) > b.push_back(m[*i]); > I could use std::copy with std::back_inserter to add elements to b, but > how do I convert it first? Should I write my own version of > back_inserter for that? > copy(a.begin(),a.end(),my_back_inserter(b,m)); > Thanks. Try this: #include <boost/lambda/lambda.hpp> using namespace boost; using namespace boost::lambda; //... //... map<int,int> m; vector<int> a,b; std::transform(a.begin(), a.end(), std::back_inserter(b), var(m)[_1]); Flex

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[MultiIndex] comparison operator
by Lukasz Dobrek 20 Sep '06

20 Sep '06

Hi, I know that there are for sure important design decisions explaining why all std containers as well as multiindex take a comparison operator, as template parameter. This behavior is satisfactory as long, as comparison is sort of context independent. The best example say ints, but there exist cases when comparison of two object requires some priory knowledge about context this objects exist in. My favorite example is tenor ( time period ). It is impossible to say whether 1 month is less then 30 days unless you know when you start counting. So in order to compare such objects I need to specify some anchor date. Unfortunately I cannot have a std::set of such objects, nor a multiindex indexed with this objects. Note: I am able to sort a vector of such objects using std::sort. First question: Is there a way to use such objects with multiindex, if not why? Second question: I cannot be the only bloke disturbed by this issue, how are you dealing with it? Regards, Lukasz Dobrek

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[Boost][Graph] Reversing a directed edge
by Young, Michael 20 Sep '06

20 Sep '06

I am a newbie to BGL - actually, I'm just beginning to build examples with it. However, I have read the first 4 chapters of "the book", and I've searched the documentation, and I haven't seen a way to reverse a specific edge within a directed (bidirectional) graph. Is there anyway to do this without removing the original edge and then adding the "reversed" edge? I have an application that requires such a "flip" of particular edges at times, but remove/add seems to be a bit "heavyweight" in terms of computation, especially when I already have identified the edge and have it accessible via an iterator. Thanks, Mike

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Re: [Boost-users] [graph] breadth_first_search with a structure
by boost＠daniel-gohlke.de 20 Sep '06

20 Sep '06

Hello Stephan, with your example I get the same errors like before. The compiler is Visual C++ 6.0 and the version number ob boost is (probably) 1.33.1. The first errors I get are: H:\daten\Programme\boost/pending/property.hpp(40) : error C2039: 'kind' : is not a member of '`global namespace'' H:\daten\Programme\boost/graph/properties.hpp(198) : see reference to class template instantiation 'boost::property_kind<long dreiDmatrix::Vertex::*>' being compiled H:\daten\Programme\Matrizen\dreiDmatrix.h(78) : see reference to class template instantiation 'boost::property_map<class boost::adjacency_list<struct boost::vecS,struct boost::vecS,struct boost::undirectedS,struct dreiDmatrix::Vertex,struct boost::no_property,struct boost::no_property,struct boost::listS>,long dreiDmatrix::Vertex::*>' being compiled This error is several times repeated. CU Daniel Am 12.09.2006 um 17:36 Uhr haben Sie geschrieben: > Please try this one (it's the altered bfs-example): > > #include <boost/graph/adjacency_list.hpp> > #include <boost/graph/breadth_first_search.hpp> > #include <boost/pending/integer_range.hpp> > #include <iostream> > > using namespace boost; > > //tag for throwing inside bfs_distance_visitor > struct max_distance_reached{}; > template < typename DistanceMap > > class bfs_distance_visitor:public default_bfs_visitor { > typedef typename property_traits < DistanceMap >::value_type T; > > public: > bfs_distance_visitor(DistanceMap dmap, T > max_distance):m_distance_map(dmap),m_max_distance(max_distance){ } > template < typename Edge, typename Graph > > void tree_edge(Edge e, const Graph & g) const > { > typename graph_traits < Graph >::vertex_descriptor > s = source(e, g), t = target(e, g); > m_distance_map[t] = m_distance_map[s] + 1; > if (m_distance_map[t] >= m_max_distance) > throw max_distance_reached(); > } > DistanceMap m_distance_map; > T m_max_distance; > }; > > //own vertex, bundles properties style > struct Vertex{ > long distance; > double probability; > }; > > int > main() > { > // Select the graph type we wish to use > typedef adjacency_list < vecS, vecS, undirectedS, Vertex> graph_t; > // Set up the vertex IDs and names > enum { r, s, t, u, v, w, x, y, N }; > // Specify the edges in the graph > typedef std::pair < int, int >E; > E edge_array[] = { E(r, s), E(r, v), E(s, w), E(w, r), E(w, t), > E(w, x), E(x, t), E(t, u), E(x, y), E(u, y) > }; > > // Create the graph object > const int n_edges = sizeof(edge_array) / sizeof(E); > typedef graph_traits<graph_t>::vertices_size_type v_size_t; > graph_t g(edge_array, edge_array + n_edges, v_size_t(N)); > > // Typedefs > typedef graph_traits < graph_t >::vertex_descriptor vertex_descriptor ; > typedef graph_traits < graph_t >::vertices_size_type vertices_size_type; > > // get the distance property map from the graph > typedef property_map<graph_t, long Vertex::*>::type tDistanceMap; > tDistanceMap distance_map = get(&Vertex::distance, g); > > //create a bfs visitor which calculates all distances smaller than 3 > bfs_distance_visitor<tDistanceMap> vis(distance_map, 3); > try{ > breadth_first_search(g, vertex(s, g), visitor(vis)); > } catch(max_distance_reached& ){} > return EXIT_SUCCESS; > } > > If this won't compile, please specify also which version of boost and > VC++ you are using. > > HTH, > Stephan > _______________________________________________ > Boost-users mailing list > <a href='email_neu.php?writeTo=Boost-users(a)lists.boost.org'>Boost-users(a)lists.boost.org</a> > <a href='http://lists.boost.org/mailman/listinfo.cgi/boost-users<br' target='_blank'>http://lists.boost.org/mailman/listinfo.cgi/boost-users<br</a> /> > > >

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program_options, description string formatting question
by Ed Johnson 20 Sep '06

20 Sep '06

Hi, Is it possible to generate a description in the following format using program_options? It is a more compact format than the program_options default. It helps keep the left hand column's max length smaller, thus preventing some excess wrapping in the description column. Compact format: [-h/--help] display usage [-p/--purpose arg] model-selection or prediction [model-selection] -d/--drug arg HIV drug to be tested [-t/--thresholds arg] low and high thresholds for drug resistance Please use only one or two values. [10] Program Options Default: -h [ --help ] display usage -p [ --purpose ] arg (=model-selection) model-selection or prediction -d [ --drug ] arg HIV drug to be tested -t [ --thresholds ] arg Thresholds for high and low resistance . Please use only 1 thresholds. In the compact case, drug is a required option, but the others are optional. So, drug does not get brackets. Also, default arguments are placed brackets at the end of the descriptor. Such as, [10] for thresholds Thanks, Ed

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Boost.Wave compiling issue
by Edmond Gheury 20 Sep '06

20 Sep '06

Hi, when trying to compile Boost.Wave (1.33.1) on AIX with VACPP 6. I got an error located in the file \boost\wave\cpplexer\re2clex\cpp_re2c_lexer.hpp, line 307, i.e. lexer<IteratorT, PositionT> lexer; First, it seems strange that a variable name matches a type name (and that's what's teeling the error message). When I replace that variable name by "lexer_" and its three remaining occurences in the "lex_functor" class, there's no more errors. So, I wonder if it is a bug popping up only on some compilers and, btw, can someone give me an explanation of how it manages to compile on msvc and g++. Thank you very much. Regards, Edmond

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[bind] Problem when bind a templated member function
by Christian Henning 19 Sep '06

19 Sep '06

Hi there, I know it must be very easy but I cannot figure it out myself. Can somehow please take a look at: class task { public: template < class T > void do_it( const T t ) { thread_ptr.reset( new boost::thread( boost::bind( (void (thread::*)(const T)) &thread::_run , this ))); } private: template < class T > void _run( const T t ) {} private: typedef boost::shared_ptr< boost::thread > thread_ptr_t; thread_ptr_t thread_ptr; }; There must be something wrong. I'm using VC2003. The comiler tells me: c:\boost\boost\bind\bind_template.hpp(18) : error C2091: function returns function Thanks ahead, Christian

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