October 2009 - Boost-users - lists.preview.boost.org

[Property map] 1.40.0 breaks boost.graph python bindings
by John Reid 13 Oct '09

13 Oct '09

I'm using gcc 4.2.4 on Ubuntu. The boost.graph python bindings (http://www.osl.iu.edu/~dgregor/bgl-python/) work fine with boost 1.39. When I try with boost 1.40 I get many errors such as the following: ./boost/graph/python/resizable_property_map.hpp:101: error: ‘class boost::vector_property_map< boost::default_color_type, boost::graph::python::basic_index_map< boost::graph::python::basic_descriptor<boost::detail::edge_desc_impl<boost::bidirectional_tag, void *>, boost::bidirectionalS>, boost::adj_list_edge_property_map< boost::bidirectional_tag, long unsigned int, const long unsigned int &, void *, const boost::property<boost::edge_index_t, long unsigned int, boost::no_property>, boost ::edge_index_t>>>’ has no member named ‘get_store’ Does anyone know what changed between 1.39 and 1.40 to break this? The Readme.txt that comes with boost 1.40 suggests that nothing was updated in the property map library. BTW it doesn't compile with gcc 4.3 either but then neither does it compile with boost 1.39 (albeit for different reasons). I can provide all of the error messages if needed. John.

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Re: [Boost-users] [Boost.MPL]is it possible to generate types
by Tan, Tom (Shanghai) 13 Oct '09

13 Oct '09

Thanks, it works like a charm. Tan, Tom (Shanghai) wrote: > I have a templated class > > template<class U, class V, class W> > class S > { > //... implementations > }; > > and some stock type implementations for type U, V and W: > > typedef boost::mpl::vector<U0, U1> u_types; > typedef boost::mpl::vector<V0, V1, V2, V3, V4> u_types; > typedef boost::mpl::vector<W0, W1, W2, W3, W4> w_types; > > I want to test class S with all possible combinations of the template > arguments, > > typedef boost::mpl::vector< > S<U0,V0,W0>, > S<U0,V0,W1>, > // ... > S<U1,V4,W4>, > > s_types; > > like this: > boost::mpl::for_each<s_types>(test_func). > > The only problem is there are 2*5*5 = 50 combinations that I do not > wish to type in one by one. > > Is there a way to generate all the combinations with boost::mpl or > Boost.Preprocessor? >> Look at BOOST_PP_SEQ_FOR_EACH_PRODUCT In Christ, Steven Watanabe ***************************************

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Re: [Boost-users] Boost-users Digest, Vol 2134, Issue 4
by Tan, Tom (Shanghai) 13 Oct '09

13 Oct '09

Thanks, it works like a charm. Tan, Tom (Shanghai) wrote: > I have a templated class > > template<class U, class V, class W> > class S > { > //... implementations > }; > > and some stock type implementations for type U, V and W: > > typedef boost::mpl::vector<U0, U1> u_types; > typedef boost::mpl::vector<V0, V1, V2, V3, V4> u_types; > typedef boost::mpl::vector<W0, W1, W2, W3, W4> w_types; > > I want to test class S with all possible combinations of the template > arguments, > > typedef boost::mpl::vector< > S<U0,V0,W0>, > S<U0,V0,W1>, > // ... > S<U1,V4,W4>, > > s_types; > > like this: > boost::mpl::for_each<s_types>(test_func). > > The only problem is there are 2*5*5 = 50 combinations that I do not > wish to type in one by one. > > Is there a way to generate all the combinations with boost::mpl or > Boost.Preprocessor? >> Look at BOOST_PP_SEQ_FOR_EACH_PRODUCT In Christ, Steven Watanabe ***************************************

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[boost C++] algorithm for shortest path
by Boost lzw 13 Oct '09

13 Oct '09

Hi there, For the following unidirectional (one-direct only) pairs: A-B; G-H; B-D; D-G; H-K; K-D; The shortest path between A and D is: A-B-D, but none between A and H. Which Boost library should I use to develop such an algorithm or any hint on design it ? Thanks in advance. Robert

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Formal Review of Boost.Polygon extended one more week: until September 9, 2009
by Fernando Cacciola 13 Oct '09

13 Oct '09

Dear boost users, The review of Boost.Polygon was initially scheduled to end today. However, the discussions are in their best moment only now so the review period was extended by one week, until September 9, 2009 (that is next Wednesday). Best Fernando Cacciola Review Manager

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[python] Alternative to explicitly defining function pointers?
by Boris Schaeling 13 Oct '09

13 Oct '09

Is it possible to simplify this code without defining a function pointer? ----- struct X { void y(std::string) { } std::string y() { return ""; } }; std::string (X::*get_y)() = &X::y; class_<X>("X").add_property("y", get_y); ----- I tried to set the signature but if the documentation is right signatures only make sense for function objects - so this code doesn't work: class_<X>("X").add_property("y", make_function(&X::y, default_call_policies(), mpl::vector<std::string>())); Anything else Boost.Python offers to make adding properties even easier? If there is nothing I know at least that I didn't miss a shortcut and have to define function pointers myself. Boris

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[PREPROCESSOR] Working around the 256 element limit for sequences
by Rush Manbert 13 Oct '09

13 Oct '09

We define exception error codes and other useful information like this: #define EXCEPTION_TABLE \ ( (enumName0, "description string", "another sting", "yet another string") ) \ ( (enumName1, "description string", "another sting", "yet another string") ) \ . . . // End EXCEPTION_TABLE def Then we write a macro that creates an enum like this: #define ENUM_ERROR_CODES(EXCEPTION_TABLE_MACRO_NAME, firstErrorCodeValue)\ public: typedef enum \ { \ \ BOOST_PP_SEQ_FOR_EACH_I(MAKE_EXCEPTION_CODE_ENUM, ~, EXCEPTION_TABLE_MACRO_NAME) \ } ErrorCodesT; \ // End macro definition and we invoke ENUM_ERROR_CODES as: ENUM_EROR_CODEAS(EXCEPTION_TABLE, 1) This has worked just beautifully until recently. Now we're trying to use this code to define an enum (and other things) based on an EXCEPTION_TABLE that carries error code for a hardware device. There are about 500 of them. I ran into the 256 element limitation for sequences. I have tried rewriting the enum macro like this: #define ENUM_ERROR_CODES(EXCEPTION_TABLE_MACRO_NAME, firstErrorCodeValue)\ public: typedef enum \ { \ \ BOOST_PP_SEQ_FOR_EACH_I(MAKE_EXCEPTION_CODE_ENUM, ~, BOOST_PP_SEQ_SUBSEQ(EXCEPTION_TABLE_MACRO_NAME, 0, 250))\ BOOST_PP_SEQ_FOR_EACH_I(MAKE_EXCEPTION_CODE_ENUM, ~, BOOST_PP_SEQ_SUBSEQ(EXCEPTION_TABLE_MACRO_NAME, 250, 250))\ BOOST_PP_SEQ_FOR_EACH_I(MAKE_EXCEPTION_CODE_ENUM, ~, BOOST_PP_SEQ_SUBSEQ(EXCEPTION_TABLE_MACRO_NAME, 500, 250))\ BOOST_PP_SEQ_FOR_EACH_I(MAKE_EXCEPTION_CODE_ENUM, ~, BOOST_PP_SEQ_SUBSEQ(EXCEPTION_TABLE_MACRO_NAME, 750, 250))\ } ErrorCodesT; \ // End macro definition thinking that I could just peel off groups of 250, but that doesn't work. I can peel off the first N, where N is <= the size of the sequence, but I certainly can't do what I wrote. Each of our exception classes is defined this way, and the number of elements in each EXCEPTION_TABLE is different for each. Is there some standard method for working around this problem? Thanks, Rush

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exception error_info list?
by denis 12 Oct '09

12 Oct '09

Hi, what do you think about exposing the error_info-map of boost::exception? I would like to get all attached error infos from one exception. Then, everyone could implement his own version of diagnostic_information() without relying on boost internals. Beside that, I had another idea: When translating an exception it would be possible to copy all error_infos from the originating exception to the new one. How do you handle this loss of information at the time? thanks.

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Numpy ndarray as argument or return value using boost python
by Pim Schellart 12 Oct '09

12 Oct '09

Hi Everyone, I tried to find a good example for this but after spending two days on google and one day getting pyublas to compile I decided to call for help. I want to give a numpy ndarray as an argument to a c++ method, calculate something and return the output as an ndarray to Python. I would prefer not to use another library (such as PyUblas) for this so I do not have to add another dependency to my program. Since the latest information on boost python is quite outdated (uses numeric) I would like to know the following. 1. Is boost python still maintained or should I switch to another tool. 2. Is numpy supported, and if so, 3. can someone give me a basic example of how to use it. Kind regards, Pim Schellart

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[BGL] read_graphviz and Bundle Properties
by Giuseppe Di Guglielmo 12 Oct '09

12 Oct '09

Dear all, here http://www.boost.org/doc/libs/1_40_0/libs/graph/doc/read_graphviz.html is reported how to use the read_graphviz function with old style "property list". How can I use the read_graphviz() function with bundle properties? This is my graph-type definition --- struct VertexId_t { std::size_t id; }; struct EdgeId_t { std::size_t id; }; typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, VertexId_t, EdgeId_t> Graph_t; --- And this is the DOT file: --- G { 0 [id="v0"]; 1 [id="v1"]; 0->0 [id="e0"]; 0->0 [id="e1"]; 0->1 [id="e2"]; } --- Cheers, G.

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