January 2010 - Boost-users - lists.preview.boost.org

[Math/Statistical Distributions+Random] Random number generation
by Marco Guazzone 07 Jan '10

07 Jan '10

Hi all! I'm a "boost newbie" so sorry for too trivial questions. Just trying to use boost for some statistical experiments, involving statistical distribution fitting, quantile generation (for goodness-of-fit tests), random variate generation, and so on. . The "Math/Statistical Distribution" library is great and almost complete. But I'm just curious why the random number generation (provided by the "Random" lib) and this library have not been integrated. For instance, the boost::random::exponential_distribution and the boost::math::exponential_distribution are two different worlds. I think a function like this below would be very helpful: --- [snip] --- template <typename Generator, typename RealType, typename Policy> inline RealType rand(Generator& rng, const exponential_distribution<RealType, Policy>& dist) { return -1.0 / dist.lambda() * std::log(1.0-rng()); } --- [snip] --- or something similar (e.g., rand implemented as a class method) In this case only two objects are needed: * boost::random::mersenne_twister * boost::math::exponential_distribution Instead, actually I have to keep different objects. For instance, for the exponential distribution: * boost::random::exponential_distribution * boost::random::mersenne_twister * boost::random::variate_generator * boost::math::exponential_distribution Unluckely I can't use boost::math::exponential_distribution in place of boost::random::exponential_distribution since boost::random::variate_generator expects a specific interface for the distribution. Well, what is the rationale behind the choice of this separation? Do you think would be useful to provide this kind of integration? Thank you very much in advance!! Cheers -- Marco

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Re: [Boost-users] BGL: shared_ptr as bundled properties > how to generate properties maps ???
by Damien Maupu 07 Jan '10

07 Jan '10

>On Wed, 6 Jan 2010, Emil Dotchevski wrote: > > On Wed, Jan 6, 2010 at 8:20 AM, Damien Maupu <damien.maupu_at_[hidden]> wrote: >>> I write something like: >>> typedef boost::shared_ptr<Vertex> VertexPtr; >>> typedef boost::shared_ptr<Edge> EdgePtr; >>> typedef adjacency_list<vecS, vecS, directedS, VertexPtr, EdgePtr> Graph; >> >> It is probably not a good idea to use shared_ptr for graphs; some >> graphs have cycles and this will lead to leaks (if your data structure >> is a DAG, you're fine.) >I don't think that will be an issue -- his shared pointers link to >properties; the graph structure itself is in BGL data structures. >However, if the properties refer to other graph vertices or edges, there >is an issue of dangling references if those objects are removed from the >graph. >-- Jeremiah Willcock Hi, I am not sure I understand why using smart pointer should be an issue. Could you explain me in little more details? Do you know how to get properties maps if bundle properties are pointer or smart pointers? Thank you Damien

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ASIO async_read_until with condition + strand
by Christophe Bourez 07 Jan '10

07 Jan '10

Can someone help with the boost async_read_until with condition ? I need to implement a request/response protocol. * A request cannot be send until the response has been completely read from the server. * Response's length from the server is unknown. The data must be parsed thanks to a parser to understand the content of the buffer. The parser is capable to return a code specifying whether the data is complete, which could require more reading on the socket. I'd like to implement my client asynchronously using ASIO. Here is the solution I implemented: the async send handler calls async_read whose handler calls async_read handler again until the message is complete. Due to the here above constraints, I am forced to queue the requests and async send the next request by the end of the handler of the current response (when it is complete, otherwize it async_reads again). I have tried to use async_read_until with a condition, but the parser was invoked very (too) often (every 2 bytes) and penalizes the performance. Would it be possible to reduce the number of calls to the condition (by reading at once the maximum of bytes present on the socket for example)? I'd like to async send the requests as soon as I can, in order to avoid the queue. Is it possible to implement a solution by using the ASIO strands? If yes, I have the feeling that the way I implemented the response handling will not work with the strand because the handler of async_read calls async_read again, which will probably come at the end of the strand's queue (which may contain many async_send requests). Could async_read_until with a condition solves this issue by avoiding to async_read again? Any help will be very appreciated. Christophe

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[thread] Getting this warning message with optimization turn on
by Shiou Ming Lee 07 Jan '10

07 Jan '10

Hi, I'm building my program that depends on Boost.thread, but getting following warning message, only when compiler's optimization been turn on. C:/boost_1_41_0/boost/thread/win32/thread_heap_alloc.hpp: In member function `bool gUtil::GLog::LogWriterManager::startAsyncLogging(unsigned int)': C:/boost_1_41_0/boost/thread/win32/thread_heap_alloc.hpp:156: warning: 'heap_memory' might be used uninitialized in this function In the mentioned function, startAsyncLogging(unsigned int), there's only one line of code that involves Boost.thread: // loggingThread is class LogWriterManager's member, of boost::thread type. loggingThread = boost::thread(boost::bind(&LogWriterManager::loggingThreadFunc, this)); This happens for MinGW 3.4 on Windows Vista SP1 32-bits, but not for GCC 4.4 on Fedora 11 x86. The Boost release is of version 1.41.0. Any idea what should I do for this warning message? Or should I just leave optimization on and ignore this message? Thanks & Regards Shiou Ming

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[Signals2] How to connect member functions with more than one argument?
by Marco Guazzone 07 Jan '10

07 Jan '10

Dear all, I am new to Boost.Signals2, so sorry for the possibly trivial question. My problem is that I am not able to connect a member function with more than one argument to a signal. My test code is the following: --- [code] --- #include <boost/bind.hpp> #include <boost/signals2.hpp> #include <iostream> template <typename IntT=int, typename RealT=double> struct event_consumer { typedef IntT int_type; typedef RealT real_type; typedef boost::signals2::signal<void (int_type,real_type)> signal_type; typedef event_consumer<int_type,real_type> self_type; void consume() { sig.connect(boost::bind(&self_type::process, this, _1)); sig(2,0.5); } void process(int_type x, real_type y) { std::cout << "X: " << x << " -- Y: " << y << std::endl; } signal_type sig; }; int main() { event_consumer<> consumer; consumer.consume(); } --- [/code] --- When I compile it (with g++ 4.4.2 and flags --ansi --Wall) I get this error: --- [error] --- $ g++ -Wall -ansi -o test_signal test_signal.cpp In file included from .../boost/bind.hpp:22, from test_signal.cpp:1: .../boost/bind/bind.hpp: In instantiation of ‘boost::_bi::result_traits<boost::_bi::unspecified, void (event_consumer<int, double>::*)(int, double)>’: ...//boost/bind/bind_template.hpp:15: instantiated from ‘boost::_bi::bind_t<boost::_bi::unspecified, void (event_consumer<int, double>::*)(int, double), boost::_bi::list2<boost::_bi::value<event_consumer<int, double>*>, boost::arg<1> > >’ test_signal.cpp:15: instantiated from ‘void event_consumer<IntT, RealT>::consume() [with IntT = int, RealT = double]’ test_signal.cpp:32: instantiated from here .../boost/bind/bind.hpp:69: error: ‘void (event_consumer<int, double>::*)(int, double)’ is not a class, struct, or union type In file included from ...//function/detail/maybe_include.hpp:23, from .../boost/function/detail/function_iterate.hpp:14, from .../boost/preprocessor/iteration/detail/iter/forward1.hpp:57, from .../boost/function.hpp:64, from .../boost/signals2/signal.hpp:18, from .../boost/signals2.hpp:16, from test_signal.cpp:2: .../boost/function/function_template.hpp: In static member function ‘static void boost::detail::function::void_function_obj_invoker2<FunctionObj, R, T0, T1>::invoke(boost::detail::function::function_buffer&, T0, T1) [with FunctionObj = boost::_bi::bind_t<boost::_bi::unspecified, void (event_consumer<int, double>::*)(int, double), boost::_bi::list2<boost::_bi::value<event_consumer<int, double>*>, boost::arg<1> > >, R = void, T0 = int, T1 = double]’: .../boost/function/function_template.hpp:913: instantiated from ‘void boost::function2<R, T1, T2>::assign_to(Functor) [with Functor = boost::_bi::bind_t<boost::_bi::unspecified, void (event_consumer<int, double>::*)(int, double), boost::_bi::list2<boost::_bi::value<event_consumer<int, double>*>, boost::arg<1> > >, R = void, T0 = int, T1 = double]’ .../boost/function/function_template.hpp:722: instantiated from ‘boost::function2<R, T1, T2>::function2(Functor, typename boost::enable_if_c<boost::type_traits::ice_not::value, int>::type) [with Functor = boost::_bi::bind_t<boost::_bi::unspecified, void (event_consumer<int, double>::*)(int, double), boost::_bi::list2<boost::_bi::value<event_consumer<int, double>*>, boost::arg<1> > >, R = void, T0 = int, T1 = double]’ .../boost/function/function_template.hpp:1064: instantiated from ‘boost::function<R(T0, T1)>::function(Functor, typename boost::enable_if_c<boost::type_traits::ice_not::value, int>::type) [with Functor = boost::_bi::bind_t<boost::_bi::unspecified, void (event_consumer<int, double>::*)(int, double), boost::_bi::list2<boost::_bi::value<event_consumer<int, double>*>, boost::arg<1> > >, R = void, T0 = int, T1 = double]’ .../boost/function/function_template.hpp:1105: instantiated from ‘typename boost::enable_if_c<boost::type_traits::ice_not::value, boost::function<R(T0, T1)>&>::type boost::function<R(T0, T1)>::operator=(Functor) [with Functor = boost::_bi::bind_t<boost::_bi::unspecified, void (event_consumer<int, double>::*)(int, double), boost::_bi::list2<boost::_bi::value<event_consumer<int, double>*>, boost::arg<1> > >, R = void, T0 = int, T1 = double]’ .../boost/signals2/detail/slot_template.hpp:156: instantiated from ‘void boost::signals2::slot2<R, T1, T2, SlotFunction>::init_slot_function(const F&) [with F = boost::_bi::bind_t<boost::_bi::unspecified, void (event_consumer<int, double>::*)(int, double), boost::_bi::list2<boost::_bi::value<event_consumer<int, double>*>, boost::arg<1> > >, R = void, T1 = int, T2 = double, SlotFunction = boost::function<void(int, double)>]’ .../boost/signals2/detail/slot_template.hpp:81: instantiated from ‘boost::signals2::slot2<R, T1, T2, SlotFunction>::slot2(const F&) [with F = boost::_bi::bind_t<boost::_bi::unspecified, void (event_consumer<int, double>::*)(int, double), boost::_bi::list2<boost::_bi::value<event_consumer<int, double>*>, boost::arg<1> > >, R = void, T1 = int, T2 = double, SlotFunction = boost::function<void(int, double)>]’ test_signal.cpp:15: instantiated from ‘void event_consumer<IntT, RealT>::consume() [with IntT = int, RealT = double]’ test_signal.cpp:32: instantiated from here .../boost/function/function_template.hpp:153: error: no match for call to ‘(boost::_bi::bind_t<boost::_bi::unspecified, void (event_consumer<int, double>::*)(int, double), boost::_bi::list2<boost::_bi::value<event_consumer<int, double>*>, boost::arg<1> > >) (int&, double&)’ --- [/error] --- Thank you very much for the support!!! Best, -- Marco

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[Preprocessor] how to use REPEAT_FROM_TO for 2 arguments
by Kai Liu 07 Jan '10

07 Jan '10

Hi, I am trying to use the preprocessor library to simplify the code I have. The problem: I have many lines of the following assignments: mybfclass x_0_mybf; mybfclass x_1_mybf; ... mybfclass1 x_0_mybf1; mybfclass1 x_1_mybf1; ... mybfclass2 x_0_mybf2; mybfclass2 x_1_mybf2; then I defined several vectors: vector<mybfclass*> x_mybf; vector<mybfclass1*> x_mybf1; vector<mybfclass2*> x_mybf2; * use the boost preprocessor library, I write the following code: #define* DECLX_mybf(z, n, text) BOOST_PP_CAT(text, BOOST_PP_CAT(_, mybf)).push_back(&BOOST_PP_CAT(text, BOOST_PP_CAT(BOOST_PP_CAT(_, n), BOOST_PP_CAT(_, mybf)))); *#define* DECLX_mybf1(z, n, text) BOOST_PP_CAT(text, BOOST_PP_CAT(_, mybf)).push_back(&BOOST_PP_CAT(text, BOOST_PP_CAT(BOOST_PP_CAT(_, n), BOOST_PP_CAT(_, mybf)))); *#define* DECLX_mybf2(z, n, text) BOOST_PP_CAT(text, BOOST_PP_CAT(_, mybf)).push_back(&BOOST_PP_CAT(text, BOOST_PP_CAT(BOOST_PP_CAT(_, n), BOOST_PP_CAT(_, mybf)))); BOOST_PP_REPEAT_FROM_TO(0, 2, DECLX_mybf, x); *// generated: x_mybf.push_back(&x_0_mybf); x_mybf.push_back(&x_1_mybf); * BOOST_PP_REPEAT_FROM_TO(0, 2, DECLX_mybf1, x); *// generated: x_mybf1.push_back(&x_0_mybf1); x_mybf1.push_back(&x_1_mybf); * BOOST_PP_REPEAT_FROM_TO(0, 2, DECLX_mybf2, x); *// generated: x_mybf2.push_back(&x_0_mybf2); x_mybf2.push_back(&x_1_mybf); * but I think it is too much coding here, since I have to write a macro for each mybf occurrence, DECLX_mybf I have difficulty to use the BOOST_PP_REPEAT_FROM_TO for two argument, since the macro(z, x, data) can only accept one argument data, however, I need to pass two arguments x and mybf to the macro, in order to generate a mybfclass1 x_0_mybf. does anyone know how to apply macro to generate the above structure? thanks. /Kenny * *

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[BGL] simple problem: how to detect connections in a dag?
by Olaf Krzikalla 06 Jan '10

06 Jan '10

Hi @boost, we have a rather simple problem here for which we however couldn't find a simple solution in the BGL. Probably because we aren't graph experts. We have a dag and two vertices in this dag. Now we just want to know if these vertices are connected (acrtually we don't need the path), that is if one vertex is in a parent chain of the other. Thanks in advance Olaf Krzikalla

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Re: [Boost-users] [asio] Sending large packages
by Nicola Michael Gutberlet 06 Jan '10

06 Jan '10

Doesn't anyone have any ideas? Did anyone receive this mail? Best regards and a happy new year ;-) _____ From: Nicola Michael Gutberlet [mailto:nicola.gutberlet@hhi.fraunhofer.de] Sent: 15 December 2009 17:28 To: 'boost-users(a)lists.boost.org' Subject: RE: [asio] Sending large packages Some testing showed that the maximum package (load) size of boost::asio::write/read() for a TCP socket seems to be 1007 kB _____ From: Nicola Michael Gutberlet [mailto:nicola.gutberlet@hhi.fraunhofer.de] Sent: 15 December 2009 17:11 To: 'boost-users(a)lists.boost.org' Subject: [asio] Sending large packages Dear all, Is there a well-defined way of sending large packages over TCP? Or do I have to split the packages on my own? For explanation: I want to send images (size around 6MB). Best regards, Nicola

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[bjam][1.41.0] Build with variant=release, debug fails
by Richard Hadsell 06 Jan '10

06 Jan '10

I am trying to build the Boost 1.41.0 libraries with this command: bin/bjam --user-config=user-config.LINUX_AMDF7 threading=multi instruction-set=opteron address-model=64 variant=release,debug,profile link=static,shared --stagedir=stageF7 stage The last time I built Boost libraries was version 1.35.0. I eliminated all of the other options to narrow the problem to just this option: variant=release,debug The build starts up successfully, if I select just one option for variant (debug or release), but it fails when I try to build both. These are the error messages: error: Duplicate name of actual target: <pstageF7/lib>libboost_date_time.a error: previous virtual target { common%common.copy-libboost_date_time.a.STATIC_LIB { gcc%gcc.archive-libboost_date_time.a.STATIC_LIB { gcc%gcc.compile.c++-gregorian/greg_month.o.OBJ { gregorian/greg_month.cpp.CPP } } { gcc%gcc.compile.c++-gregorian/greg_weekday.o.OBJ { gregorian/greg_weekday.cpp.CPP } } { gcc%gcc.compile.c++-gregorian/date_generators.o.OBJ { gregorian/date_generators.cpp.CPP } } } } error: created from ./stage-proper error: another virtual target { common%common.copy-libboost_date_time.a.STATIC_LIB { gcc%gcc.archive-libboost_date_time.a.STATIC_LIB { gcc%gcc.compile.c++-gregorian/greg_month.o.OBJ { gregorian/greg_month.cpp.CPP } } { gcc%gcc.compile.c++-gregorian/greg_weekday.o.OBJ { gregorian/greg_weekday.cpp.CPP } } { gcc%gcc.compile.c++-gregorian/date_generators.o.OBJ { gregorian/date_generators.cpp.CPP } } } } error: created from ./stage-proper error: added properties: <debug-symbols>on <inlining>off <optimization>off <runtime-debugging>on <variant>debug error: removed properties: <debug-symbols>off <define>NDEBUG <inlining>full <optimization>speed <runtime-debugging>off <variant>release /netDISKS/cgi/LINUX_AMD64/cgi/vendor/library/boost/boost_1_41_0/tools/build/v2/build/virtual-target.jam:490: in actualize-no-scanner from module object(file-target)@4821 /netDISKS/cgi/LINUX_AMD64/cgi/vendor/library/boost/boost_1_41_0/tools/build/v2/build/virtual-target.jam:135: in object(file-target)(a)4821.actualize from module object(file-target)@4821 /netDISKS/cgi/LINUX_AMD64/cgi/vendor/library/boost/boost_1_41_0/tools/build/v2/build-system.jam:717: in load from module build-system /netDISKS/cgi/LINUX_AMD64/cgi/vendor/library/boost/boost_1_41_0/tools/build/v2/kernel/modules.jam:283: in import from module modules /netDISKS/cgi/LINUX_AMD64/cgi/vendor/library/boost/boost_1_41_0/tools/build/v2/kernel/bootstrap.jam:142: in boost-build from module /netDISKS/cgi/LINUX_AMD64/cgi/vendor/library/boost/boost_1_41_0/boost-build.jam:17: in module scope from module The user-config contains just these 2 lines: using gcc : 4.1.2 : /usr/bin/g++ : <compileflags>"-fPIC -fno-strict-aliasing -fno-tree-ccp" <linkflags>"-fPIC -fno-strict-aliasing -fno-tree-ccp" ; using python : 2.5 : /usr ; It seems possible that the libraries would build correctly in separate steps, but I am concerned that the debug, release, and profile versions will be mixed up. Is this just a problem for the date_time library, or is there something wrong with the build rules? If someone can give me a reliable workaround, I would appreciate it. (I am building with g++ 4.1.2 on a Fedora 7 x86_64 Linux system.) -- Dick Hadsell 203-992-6320 Fax: 203-992-6001 Reply-to: hadsell(a)blueskystudios.com Blue Sky Studios http://www.blueskystudios.com 1 American Lane, Greenwich, CT 06831-2560

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Reducing the size of .obj file which does serialization
by Gokulakannan Somasundaram 06 Jan '10

06 Jan '10

Hi, I have a parent class which has around 200 sub-classes. While serializing the entire hierarchy, i have lot of base class pointers and STLs of base class pointers. From the documentation, i found that if i have to serialize the polymorphic pointers, then i have to do a BOOST_EXPORT of all the relevant subclasses. But after doing that, i find my .obj file to be around 37MB. I am using the text archive in my code. When i tried the polymorphic_text_archive, the size only reduced by 3MB. Can someone help me on how i should go about reducing the .obj file size? Some of my questions are a) One approach, i could think of is to create a virtual function in the hierarchy, which just takes the Archive and does the serialization. This would help me, because i don't need to have the BOOST_EXPORT, which increases the size of the .obj file. b) Why is BOOST_EXPORT required for polymorphic_text_archive? Since it anyway uses virtual functions instead of templates, why does it need the derived class definition. Thanks, Gokul.

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