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Boost Python is slow?
by Tyomich on the AIR 13 Jul '09

13 Jul '09

Hello everyone! I'm currently embedding Python and have a problem. I have a struct (point) which looks like struct TPoint { int x, y; }; And I want it to be usable from Python. I made it in two ways: the first one was writing all the warpping by myself according to Python/C API, and the second was wrap it with Boost.Python. So it looks like class_<TPoint>("TPoint") .def_readwrite("x", &TPoint::x) .def_readwrite("y", &TPoint::y); It wraps ok but here is a problem: I create a huge (1000000 items) list of objects of that type: def cr_fig(n): res = [] while n>0: res.append(TPoint()) n -= 1 return res And then when I use a simple function which just increments the x member of every object, this function takes about 4 seconds to process the whole list (1000000 items) of Boost-wrapped objects and less than a second to process objects of my own wrapping! How this can be possible? Is Boost.Python much more slower than Python itself? Regards, Artyom Chirkov. P.S. I couldn't find out how to write to Boost.Python community, so I wrote here. If anyone knows how to do that, please let me know!

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[Thread] Can't suppress thread_specific_ptr 'memory leak'
by Joshua Boyce 13 Jul '09

13 Jul '09

Hey all, having a small issue with thread_specific_ptr. I'm a MSVC user and I'm getting a memory leak reported with the leak detection from _CrtSetDbgFlag and I was wondering if it was possible to suppress it somehow? I only ask because I know that these leaks in particular are false positives (or so it seems) and I wish to filter them out so I can quickly see each time if anything else is leaking without having to "manually" filter the log myself. Thanks.

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Re: [Boost-users] A question on data change with lambda expression. Can any one with kindness help me?
by fmingu 13 Jul '09

13 Jul '09

Can any experts with kindness help me? I really need the answer. I have tried my best to program with c++. And I want to be familiar with lambda. Thanks a lot.

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[phoenix] how to compare std:string
by Michael Caisse 12 Jul '09

12 Jul '09

Hi all - I have a vector of std::pair< std::string, int > and I want to use std::find_if to get the location where the std::pair first is some string value. I have successfully performed the correct incantation to compare the std::pair second to an int; however, it eludes me to what I need for the string. This is my test ---------------------------------- #include <vector> #include <algorithm> #include <boost/spirit/home/phoenix/core.hpp> #include <boost/spirit/home/phoenix/operator.hpp> #include <boost/spirit/home/phoenix/bind/bind_member_variable.hpp> int main() { using namespace boost::phoenix; using namespace boost::phoenix::arg_names; typedef std::pair< std::string, int > node_type; typedef std::vector< node_type > node_storage_type; node_storage_type my_nodes; my_nodes.push_back( std::pair< std::string, int >( "foo", 8 ) ); // this works great node_storage_type::iterator iter = std::find_if( my_nodes.begin(), my_nodes.end(), bind( &node_type::second, arg1 ) == 8 ); // compilation error here: ..\..\..\library\vendor\boost_1_38_0\boost/spirit/home/phoenix/operator/comparison.hpp(27) : error C2678: binary '==' : no operator found which takes a left-hand operand of type 'std::basic_string<_Elem,_Traits,_Ax>' (or there is no acceptable conversion) // iter = std::find_if( my_nodes.begin(), my_nodes.end(), bind( &node_type::first, arg1 ) == "foo" ); return 0; } Thanks ! michael -- ---------------------------------- Michael Caisse Object Modeling Designs www.objectmodelingdesigns.com

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playing around with tutorial codes to understand ioservice
by Ozgur Ozturk 11 Jul '09

11 Jul '09

Hi, I have been working on asio from the online documentation for more than a week but I am still confused about the io_service. Especially about what happens when we pass io_service to so many other things (timer, socket, chat_client etc.)? I hoped playing around with the codes in tutorial may help me in understanding. I modified the code a bit from timer3.cpp example<http://www.boost.org/doc/libs/1_39_0/doc/html/boost_asio/tutorial/tuttimer3…>. (modified code is in attachment) When I add another io_service object, I was thinking one would run then the other one would start since in the comments of io_service.hpp it says * The run() function blocks until all work has finished and there are no * more handlers to be dispatched, or until the io_service has been stopped. but when I run two io_service objects io.run(); io2.run(); I get output from two of them interchangingly. (first print in each line is address of deadline timer, I added in print function to see which thread is running.) 0012FF04 0 0012FEE4 1 0012FEE4 2 0012FEE4 3 0012FF04 4 Could someone help me understand io_service class? (Maybe some pointers to old discussions could help.) I also read some papers about Proactor pattern, without too much help. Maybe example code can be supplied with more comments. I would also appreciate suggestions and pointers (probably in private emails to ozgur7 AT gmail com) to help me about implementing a simple command server (proxy). I am trying to implement a server to accept clients and run MySQL queries (example: look up name and password pair in a table) and pass results to clients. I am using connector/C++ for MySQL part, and that part seems very easy. However I am having difficulty in understanding asio. Do you think, I am overkilling for such a simple thing. (I thought it could pay back later when I needed to improve my program...) Thanks in advance, Best regards, Ozgur (Oscar) Ozturk www.DrOzgur.com +1 (614) 805-4370

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Binding operator <<
by Archie14 11 Jul '09

11 Jul '09

Can't figure out the proper sintax for binding <<. class A { public: friend std::ostream& operator << (std::ostream& stream, A& a); }; class B : boost::ptr_vector<A> { public: friend std::ostream& operator << (std::ostream& stream, B& b); } std::ostream& operator << (std::ostream& stream, B& b) { std::for_each(begin(), end(), boost::bind(&operator<<, ref(stream), ref(_1)); ??? return stream; }

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Re: [Boost-users] boost programmer_option.hpp
by Narendra R 11 Jul '09

11 Jul '09

hi Markus , Steeps i have done is 1. downloaded boost library boost_1_39_0 2. build the program.option using bootstrap.sh --without-libraries=program_options --libdir=/home/narendra/boost_instal/boost_1_39_0/b_lib_ins where /home/narendra/boost_instal is the directory where i have stored boost library I tried to link like this g++ -I /home/narendra/boost_instal/boost_1_39_0 test.cpp -o test -L /home/narendra/boost_instal/boost_1_39_0/stage/lib -l/home/narendra/boost_instal/boost_1_39_0/stage/lib/libboost_program_options-gcc41-mt-1_39.a

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[Program Options] Difficulty compiling for static runtime library
by Lindley M French 11 Jul '09

11 Jul '09

I have a large project that I'd like to use Boost.Program Options with. Most of the other Visual Studio 2005 projects are set to link against "Multithreaded" or "Multithreaded Debug" rather than the DLL variants of same; so of course, I need to build Program Options accordingly. I tried this: bjam.exe" release --runtime-link=static program_options But that did not produce the library that VS wants, which is: libboost_program_options-vc80-mt-s-1_39.lib Actually, that build setting caused program_options to throw a massive number of warnings, mostly stuff like: .\boost/program_options/detail/cmdline.hpp(128) : warning C4251: 'boost::program_options::detail::cmdline::m_style_parser' : class 'boost::function1 ,T0>' needs to have dll-interface to be used by clients of class 'boost::program_options::detail::cmdline' with [ R=std::vector<boost::program_options::option>, T0=std::vector<std::string> & ] and also .\boost/program_options/errors.hpp(21) : warning C4275: non dll-interface class 'std::logic_error' used as base for dll-interface class 'boost::prog m_options::error' C:\Program Files (x86)\Microsoft Visual Studio 8\VC\INCLUDE\stdexcept(22) : see declaration of 'std::logic_error' .\boost/program_options/errors.hpp(21) : see declaration of 'boost::program_options::error' Any ideas?

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re gularized gamma incomplete function (v 1.39)
by darthshak 10 Jul '09

10 Jul '09

I am using boost v1.39 libraries on Ubuntu 9.04. This is the first time I am using the boost libraries for some mathematical work. I needed to use the regularized incomplete gamma function for one of my programs. The documentation told me that gamma_q was the upper incomplete gamma function for the job. So I tried the syntax gamma_q(a,b) and I got an error saying "gamma_q was not declared in this scope". Realizing that the boost libraries were in /opt/boost, I compiled with the following : g++ ggpdf.cpp -I /opt/boost/include/boost-1_39/ I included the boost header with a #include<boost/math/special_functions/gamma.hpp>. I stil got the same error (gamma_q was not declared in scope). I then thought that I should link the libraries manually and then tried g++ ggcdf.cpp -I /opt/boost/include/boost-1_39/ -L /opt/boost/lib/ ...and still no luck. Also, the size of my /opt/boost folder is only 65M, which seems kind of small. Am I missing some incantation here for compiling or is it just an incomplete install? -- View this message in context: http://www.nabble.com/regularized-gamma-incomplete-function-%28v-1.39%29-tp… Sent from the Boost - Users mailing list archive at Nabble.com.

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newbie weighted edges question
by Fahad Saeed 10 Jul '09

10 Jul '09

Hello everyone, I am new at using Boost libraries and was hoping that someone could give me some pointers how to start.The problem that I want to solve is as follows: I want to build a directed graph model with edges that are weighted.But instead of having one weight each edge is suppose to have 2 weights, each representing a different parameter in my graph model.The weights are to be used separately for different functions. Also, this is trivial but a pointer would certainly help. I would like to take each vertice in the graph and ¨know¨ its immediate neighbours. Thanks in advance. Fahad

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