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

Re: [Boost-users] 3 times slower than c++
by Sohail Somani 11 Sep '06

11 Sep '06

> -----Original Message----- > From: boost-users-bounces(a)lists.boost.org > [mailto:boost-users-bounces@lists.boost.org] On Behalf Of > Qinfeng(Javen) Shi > Sent: Monday, September 11, 2006 3:46 AM > To: boost-users(a)lists.boost.org > Subject: Re: [Boost-users] 3 times slower than c++ > > Dear all, > > We are writing a python toolbox and wrapping it from c++ is > much faster than pure python. > But my wrapped c++ code(called in python) is 3 times(not plus > a constant time) slower than the orignial c++ one. > > I think the difference should be a constant not a factor. > Because all the computation has been taken in *.so, the extra > time cost is the time python load it at the beginning. > Is that right? > > Any opinion or suggestion about why or how to speed it up? Are you wrapping with boost.python?

1 0

3 times slower than c++?
by Qinfeng(Javen) Shi 11 Sep '06

11 Sep '06

Dear all, I wrapped a c++ code into python. It works but it is 3 times slower than the orignial c++ one. Is that normal? Is there something I can do to speed it up? Thanks! -- Qinfeng(Javen) Shi Research School of Information Sciences and Engineering Australian National University Locked Bag 8001 Canberra ACT 2601

4 4

Re: [Boost-users] array of strings in boost python
by ctrembla＠pcigeomatics.com 11 Sep '06

11 Sep '06

In article <87k64aad0w.fsf__22758.9953029112$1157972153$gmane $org(a)pereiro.luannocracy.com>, dave(a)boost-consulting.com says... > <ctrembla(a)pcigeomatics.com> writes: > > > Hi, > > > > newbie in python and boost::python > > Please post Boost.Python questions to the C++-sig: > http://www.boost.org/more/mailing_lists.htm#cplussig > > > I have a method in c++ that returns a vector of strings, how can i > > expose this method in python, and how should i use it in python > > Sorry to turn the question around on you, but how do you /want/ to be > able to use it in Python? That will determine how you should expose > it. > > You might look into > http://boost.org/libs/python/doc/v2/indexing.html#vector_indexing_suite_cla… > to see if it meets your needs. > > > hi, i have exposed my c++ class using the python.boost BOOST_PYTHON_MODULE(pysession) { class_<Session> >("Session") .def("Connect" ,&Session::Connect) .def("Disconnect",&Session::Disconnect) .def("SaveSession",& Session::SaveSession) .def("SaveSessionAs", &Session ::SaveSessionAs) .def("DeleteSession", & Session::DeleteSession) .def("GetListOfServer",& Session ::GetListOfServer) ; class_<std::vector<std::string> >("STD_String") .def(vector_indexing_suite<std::vector<std::string> >()) ; } i have compiled and it generated my pyd now in python , this is were i'm stuck, i was able to retreive the iterator, how can i iterate and how can i retreive the string within the vector? oString = self.oLogin.GetListOfServer() i=0 oList = range(oString.__len__()) oIter = oString.__iter__() for i in oList: oIter = oIter.next() error log oIter = oIter.next() TypeError: No Python class registered for C++ class class std::basic_string<char ,struct std::char_traits<char>,class std::allocator<char> > thanks, charles.

1 0

boost::thread_group signal for exception and exit
by Andrew Wingorodov 11 Sep '06

11 Sep '06

What interface exists for to send a signal of exit for boost::thread ? -- andr.ru

1 0

Link error with boost regex and STLport
by Gérald FAUVELLE 11 Sep '06

11 Sep '06

Hello, I've searched in both stlport and boost forums, but I couldn't find anything yet about my problem. I'm using boost 1.33, and I tried to compiled with STL port. Boost compiles fine (except boost python, but I'll have a look later) and when I link my program, I have the following errors : boost.lib(w32_regex_traits.obj) : error LNK2019: unresolved external symbol "__declspec(dllimport) public: __thiscall stlp_std::basic_string<unsigned short,class stlp_std::char_traits<unsigned short>,class stlp_std::allocator<unsigned short> >::basic_string<unsigned short,class stlp_std::char_traits<unsigned short>,class stlp_std::allocator<unsigned short> >(unsigned short const *,class stlp_std::allocator<unsigned short> const &)" Do you have an idea of what could be the problem, and how to solve it ? I tried with STLport 4.6.2, 5.0.2 and 5.1, and I have the same error. Thanks, Gérald

3 7

Lock pointer implementation
by Mattias Brändström 11 Sep '06

11 Sep '06

Hello! I have a small class that I would like to get some feedback on. If you have the time. =) What I would like to do is to protect an instance of some class T with a mutex. It seems to me that I would be able to do this with a smart pointer that returns a proxy class, from operator->(), that locks a mutex in its constructor and unlocks it in its destrcutor. This is my intitial implementation of such a class: #include <boost/shared_ptr.hpp> #include <boost/thread.hpp> template <typename T> class LockPointer { public: class LockProxy { public: LockProxy(boost::shared_ptr<T> p, boost::shared_ptr<boost::recursive_mutex> mutex) : p_(p), lock_(new boost::recursive_mutex::scoped_lock(*mutex)) { } boost::shared_ptr<T> operator->() { return p_; } private: boost::shared_ptr<T> p_; boost::shared_ptr<boost::recursive_mutex::scoped_lock> lock_; }; LockPointer(boost::shared_ptr<T> o) : p_(o), mutex_(new boost::recursive_mutex()) { } LockProxy operator->() { return LockProxy(p_, mutex_); } private: boost::shared_ptr<T> p_; boost::shared_ptr<boost::recursive_mutex> mutex_; }; What do you think? Would this work? Would this be equivalent to locking a member mutex in each method of T (as long as all calls to an instance of T is invoked via the same LockPointer)? For some reason this is the kind of thing I would expect to find in boost, but I have not been able to. Have I missed some part of boost that I should know about? Regards, Mattias

3 3

Properties (newbie)
by Olivier Tournaire 10 Sep '06

10 Sep '06

Hi all, I am a new boost user (2 days old ...). I just want to know a few things. 1. I use an adjacency_list with my own properties to store my graph. I just want to know if it is possible to manipulate directly the properties' values. At the moment, I use get(...) to obtain the property, make my change, and use put(...) to set the new value. 2. My graph cannot contain parallel edges, so I use a setS. However, the documentation says that listS or vecS is more efficient in time and space complexity. Is it possible to use std::vector or std::list and to disallow parallele edges ? Thanks in advance Olivier

1 0

[string_algo] wildcard support?
by Richard Dingwall 10 Sep '06

10 Sep '06

Hi, I was wondering if boost string algorithms library has any support for "wildcard" characters (eg * and ?). If not... then I'm open to suggestions :) Cheers, Richard

4 5

having a problem seeding random number generator.
by Jim Ingram 10 Sep '06

10 Sep '06

I'm just starting out with boost, and I'm playing around with the random library. I'm writing a class that is supposed to simulate a six-sided die. It compiles and everything works, except seeding the mt19937. Every time I try testing this class, I get the same numbers, no matter what value I call my seed method with. If I use the constructor that takes a seed value, I get different numbers, but reseeding the object still doesn't seem to have any effect. Any ideas? #include <boost/random.hpp> class D6 { typedef boost::mt19937 engine_t; typedef boost::uniform_int<> dist_t; typedef boost::variate_generator<engine_t, dist_t> gen_t; public: D6() : engine(), six(1, 6), die(engine, six) { } D6(boost::uint32_t s) : engine(s), six(1, 6), die(engine, six) { } int roll() { return die(); } // This method seems to do nothing. void seed(boost::uint32_t s) { engine.seed(s); } private: engine_t engine; dist_t six; gen_t die; };

3 5

Graph library read_graphviz linker problem Visual C++ 7.1
by hadi khani 10 Sep '06

10 Sep '06

Hi everybody, First I want to point out that I am very immature with Boost library, and my problem may seem very simple for you; but I would be grateful if you help me. I am trying to use Graph library especially read_graphviz function to load a DOT file. I accomplished the following steps in Visual C++ 7.1 1. Download boost_1_33_1 2. Download bjam file for windows 3. Building libbgl-viz.lib by run "bjam "-sTOOLS=vc-7_1"" command in \boost_1_33_1\libs\graph\build folder 4. Setting path for libbgl-viz.lib and other Header file in the proper dialog Tools>Options>VC++ Directories 6. At this point I try to Build and compile one of Garaph example, cc-internet.cpp, I got a linker error for read_graphviz. Any help would be appreciated. Hadi Khani Hadi Khani --------------------------------- Get your own web address for just $1.99/1st yr. We'll help. Yahoo! Small Business.

2 1