- Boost-users - lists.boost.org

Re: [Boost-users] [asio] asio-client only connects to server when on same machine
by Jason Felice 14 Jan '10

14 Jan '10

On Thu, Jan 14, 2010 at 10:25 AM, Nicola Michael Gutberlet <Nicola.Gutberlet(a)hhi.fraunhofer.de> wrote: > Just an idea popping up in my mind: firewall? More likely, the server binds to localhost (loopback).

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boost python macro hell
by Neal Becker 14 Jan '10

14 Jan '10

Probably OT, but I'm trying to generate modules programmatically. Each module with be generated using -DSIMCASE=n and will create a module called ldpc_n.so. I can't get this macro to work, this is my latest try: #define SIMCASE 10 #define NAME ldpc_ ## SIMCASE #define MODULE_START BOOST_PYTHON_MODULE (NAME) Later I have: MODULE_START { ... } Results in: In file included from ldpc_x.cc:12: ldpc.cc: In function 'void initldpc_SIMCASE()': ldpc.cc:100: error: 'init_module_ldpc_SIMCASE' was not declared in this scope Looks like 2 problems there: 1 is that 'SIMCASE' did not have it's #defined value substituted, second is that (as evidenced by the error) this interacted wierdly with the BOOST_PYTHON_MODULE macro.

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Re: [Boost-users] variadic template function using fusion vector
by noman javed 14 Jan '10

14 Jan '10

We want to hide from user the creation of the vector. The user just need to call the execute function like that execute(FOB,bar1,bar2,...,barn). Where the FOB is any function object followed by the original data. Regards Noman Javed

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[variant][graph] Conflict ?
by Maxime van Noppen 14 Jan '10

14 Jan '10

Hi, I recently upgraded the boost version used four our project from boost 1.39 to boost 1.41 and encountered a very strange compilation error. I managed to reduce the problem to this minimal test case : ----------var.cc--------------- #include <boost/variant.hpp> #include <boost/graph/breadth_first_search.hpp> int main() { boost::variant<char, bool> v; boost::get<int>(v); } ---------------------------- This doesn't compile on Linux 64bits with gcc 4.4.2 20091208 and produces this error message : ---------------------------- > In file included from /usr/include/boost/graph/graph_concepts.hpp:17, > from /usr/include/boost/graph/breadth_first_search.hpp:21, > from var.cc:2: > /usr/include/boost/property_map/property_map.hpp: In instantiation of ‘boost::property_traits<int>’: > /usr/include/boost/graph/two_bit_color_map.hpp:46: instantiated from ‘boost::two_bit_color_map<int>’ > var.cc:8: instantiated from here > /usr/include/boost/property_map/property_map.hpp:31: error: ‘int’ is not a class, struct, or union type > /usr/include/boost/property_map/property_map.hpp:32: error: ‘int’ is not a class, struct, or union type > /usr/include/boost/property_map/property_map.hpp:33: error: ‘int’ is not a class, struct, or union type > /usr/include/boost/property_map/property_map.hpp:34: error: ‘int’ is not a class, struct, or union type ---------------------------- Could there be a conflict between boost.variant and boost.graph or did I miss something ? Thanks, -- Maxime

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[asio] asio-client only connects to server when on same machine
by Grotjahn Clemens (CM-AI/PJ-CF22) 14 Jan '10

14 Jan '10

hi everybody, i have an issue with my asio-client that wants to connect to an asio-server. when i set my server on a machine in our network to listening on a port (>1024) and then try to connect with my client via this port, i get a "Connection refused"-exception. this happens every time the server and client are located on different machines. if i try this on the same machine it works fine! also, if i try to connect via telnet from another machine it works! here's the client-setup-code snippet, maybe i missed a special config there?: tcp::resolver resolver( _io ); //_io is class-member tcp::resolver::query query( server, port ); //server and port are char-buffers tcp::resolver::iterator iter = resolver.resolve( query ); _socket = new tcp::socket( _io ); tcp::resolver::iterator end; // End marker. boost::system::error_code error = error::host_not_found; while (error && iter != end) { _socket->close(); _socket->connect(*iter++, error); } if (error) throw boost::system::system_error( error ); } catch( std::exception& e ) { cout << "NetClient Konstruktor: " << e.what() << endl; }

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[GIL] Black filled or not ?
by Eloi Du Bois 14 Jan '10

14 Jan '10

Hi all ! I would like to know, when creating an image like that: rgb32f_image_t img(w, h); is the image filled with 0 by default or should I call fill_pixels ? Thank you ! Eloi.

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Re: [Boost-users] [math][special_functions] Why is cbrt(x) slower than pow(x, 1/3)?
by Tim Odenthal 14 Jan '10

14 Jan '10

On Thursday 14 January 2010 07:14:28 boost-users-request(a)lists.boost.org wrote: > So I tried to improve performance on my first guess, namely > > > pow(x, > > 1/3) using boost::math::cbrt(). To my astonishment, this is much slower > > than > > the original code. I wrote a small test program to check this claim; > > compiling > > with g++ (Ubuntu 4.4.1-4ubuntu9) 4.4.1 (-O3) on a Intel Core i7 CPU I get > > the > > following timings (averaging the time over 10 trials): > > average time to compute 5000000 roots with pow(): 0.603 s. > > average time to compute 5000000 roots with boost::cbrt(): 1.087 s. > > average time to compute 5000000 roots with improved boost::cbrt(): 1.015 > > s. > > average time to compute 5000000 roots with exp(1/3*log()): 0.541 s. > > I'll investigate that - I admit I haven't profiled that function up till > now - and I suspect you're on the right lines by suspecting that the > current implementation may be slow in finding the initial starting guess. > > I suspect that some of the std:: functions may be faster if they're > implemented as intrinsics, BTW have you tried ::cbrt in math.h ? > > Cheers, John. > Hi! Thanks a lot for the suggestion: I didn't know that std::cbrt() exists! I alway relied on cplusplus.com as reference; I will have to change that! Of course this is again a lot faster: average time to compute 5000000 roots with pow(): 0.613 s. average time to compute 5000000 roots with cbrt(): 0.464 s. Thanks again - I am happy now... ;-) Tim

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[regex] Generate matching string
by Roland Bock 14 Jan '10

14 Jan '10

Hi, given a regex, is there a way to create sample strings which would match? Of course, for many patterns, the number of possible strings would be practically infinite. But sometimes it would be helpful to have even one sample of a matching string. Any ideas? Thanks and regards, Roland

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asio: selective cancellation of reads/writes
by Alexander Fritze 14 Jan '10

14 Jan '10

Hi, In asio, if I have a socket with pending asynchronous reads and writes, is there a way to selectively cancel only the reads or only the writes? All I can find is basic_stream_socket::cancel() which closes *all* pending operations on the socket. Thanks for any help, Alex

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trouble with spirit (boost 1.39)
by Noah Roberts 13 Jan '10

13 Jan '10

void read_formula_line(esi::string_t const& line, table_fluid_data & data) { namespace sp = boost::spirit::classic; using namespace sp; unsigned int index = 0; parse_info<wchar_t const*> info = sp::parse(line.c_str(), // begin grammar ( L'P' >> uint_p[assign_a(index)] //>> uint_p[assign_a(data.formulas[index-1].formula_id)] >> uint_p[boost::bind(&assign_i, _1, boost::ref(data.formulas [index-1].formula_id))] >> real_p[boost::bind(&assign_dbl, _1, boost::ref(data.formulas [index-1].coefficients[0]))] //>> real_p[assign_a(data.formulas[index-1].coefficients[0])] >> real_p[assign_a(data.formulas[index-1].coefficients[1])] >> real_p[assign_a(data.formulas[index-1].coefficients[2])] >> real_p[assign_a(data.formulas[index-1].coefficients[3])] >> real_p[assign_a(data.formulas[index-1].coefficients[4])] >> lexeme_d[*space_p] // necessary to clip off the last bit. ) , space_p); if (!info.full) throw std::runtime_error("Parse fail in formula line."); } The line is being parsed by the above code but the values are not being assigned by the assign_a nor by the boost::bind call to my own val = x setters. The setters are being called correctly, but the data is not getting through for some reason. It's like the data structure is being copied instead of referenced but I'm explicitely using references. Any idea what gives?

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