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

[Boost.Asio] Is there a way to find out first address of first NIC in the local host using Asio?
by Javier Estrada 21 Oct '09

21 Oct '09

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[boost.datetime] outputting to a widestring
by Sean Farrow 21 Oct '09

21 Oct '09

Hi: Is thee a version of the toiso_extended_string for wide character output? I have the following line: std::wstring test =boost::to_iso_extended_wstring(d); wich I assumed would work and fails. Any ideas? Cheers Sean.

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date time format
by Sean Farrow 21 Oct '09

21 Oct '09

Hi: Within a string I have a date in the format: 22 July 2009 How can I input this in to the boost::datetime library as I need to transform it in to another format. As far as I can tell, the constructor of boost::gregorian::date doesn't takethis format as one of it's string parameters. Cheers Sean.

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Re: [Boost-users] [pool] Singleton implementation
by Paul Byrne 21 Oct '09

21 Oct '09

> > Message: 8 > Date: Tue, 20 Oct 2009 06:43:40 -0800 > From: "Robert Ramey" <ramey(a)rrsd.com> > To: boost-users(a)lists.boost.org > Subject: Re: [Boost-users] [pool] Singleton implementation > Message-ID: <hbkeik$jah$1(a)ger.gmane.org> > > You might want to look at the singleton which is part of the serialization > library. > > Robert Ramey > Thanks Robert, Ray et al for the useful pointers.

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Boost.Python: wrapping OpenSceneGraph smart pointers, again
by Randolph Fritz 20 Oct '09

20 Oct '09

What is wrong with the following code? I suspect I'm doing something silly, and I suspect the answer is obvious. #include <osg/Node> #include <osg/ref_ptr> #include <boost/python.hpp> #include <boost/python/pointee.hpp> using namespace osg; typedef ref_ptr<Node> NodePtr; using namespace boost::python; BOOST_PYTHON_MODULE(NodePtr) { class_<NodePtr, pointee<NodePtr> >("NodePtr") ; } -- Randolph Fritz design machine group, architecture department, university of washington rfritz(a)u.washington.edu -or- rfritz333(a)gmail.com

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error setting up boost on visual c++ 6.0
by pedro chaparro 20 Oct '09

20 Oct '09

hi, i wanna use boost libraries over visual c++, i have followed all steps in the getting start guide for windows, but even so i get error, what could be the cause? thanks Compiling... example.cpp c:\documents and settings\juan antonio\escritorio\boost_1_40_0\boost_1_40_0\boost\aligned_storage.hpp(65) : error C2989: 'aligned_storage_imp<0,alignment_>' : template class has already been defined as a non-template class c:\documents and settings\juan antonio\escritorio\boost_1_40_0\boost_1_40_0\boost\aligned_storage.hpp(65) : error C2988: unrecognizable template declaration/definition c:\documents and settings\juan antonio\escritorio\boost_1_40_0\boost_1_40_0\boost\type_traits\floating_point_promotion.hpp(78) : fatal error C1506: unrecoverable block scoping error Error executing cl.exe. example.obj - 3 error(s), 0 warning(s) -- Ing Pedro Alonso Chaparro Valero Ciudad Politecnica de la Innovación iTEAM - Mobile Communications Group Polytechnic University of Valencia C\ Camino de Vera S/N, Edificio 8G 46022 Valencia, Spain

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[pool] Singleton implementation
by Paul Byrne 20 Oct '09

20 Oct '09

Hi all, I am interested to find a sound C++ implementation of a Singleton, and have attempted to find one within the Boost libraries. It seems that "pool/detail/singleton.hpp" would fit the bill for me, but (as I understand it) this class/header is not intended for direct use by library users. Have I overlooked a good alternative within the Boost suite? Thanks, Paul

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building boost with python script
by Michał Nowotka 20 Oct '09

20 Oct '09

Hello I want to build boost library with python scrpt(s) (maybe SCons shuld be used). Or maybe someone has already done so - I don't want to reinvent the wheel. -- Regards Michał Nowotka

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[Boost.Python] Using Inheritance *and* Virtual Functions in a Python Binding
by Dan Bailey 20 Oct '09

20 Oct '09

Hi, I can't seem to get inheritance and virtual functions to work together in a simple python binding: #include <boost/python.hpp> using namespace boost::python; struct Base { virtual ~Base() { } void nonVirtualFunc() { } virtual void virtualFunc() { } }; struct Derived : public Base { ~Derived() { } void virtualFunc() { } }; struct BaseWrap: public Base, public wrapper<Base> { void virtualFunc() { if (override virtualFunc = this->get_override("virtualFunc")) virtualFunc(); else Base::virtualFunc(); } void default_virtualFunc() { this->Base::virtualFunc(); } }; BOOST_PYTHON_MODULE(test) { class_<Base, boost::noncopyable>("__Base") .def("nonVirtualFunc", &Base::nonVirtualFunc) ; class_<BaseWrap, boost::noncopyable>("Base") .def("virtualFunc", &Base::virtualFunc, &BaseWrap::default_virtualFunc) ; class_<Derived, bases<Base> >("Derived") .def("virtualFunc", &Derived::virtualFunc) ; } Now in my python interpreter: >>> import test >>> dir(test.__Base) [<built-ins>, 'nonVirtualFunc'] >>> dir(test.Base) [<built-ins>, 'virtualFunc'] >>> dir(test.Derived) [<built-ins>, 'virtualFunc'] Without using BaseWrap to do the virtual functions: >>> dir(test.Derived) [<built-ins>, 'nonVirtualFunc', 'virtualFunc'] It seems that by using the boost python wrapper, I now lose any inherited functions, and the nonVirtualFunc does not get defined in the subclasses. I may be going about this in the wrong way, but is there a way of using inheritance and virtual functions together? Thanks, Dan

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poor boost::mpi performance
by Jonas Juselius 20 Oct '09

20 Oct '09

Hi! I'm using the boost::mpi library for a HPC project. I really like the interface, but I'm currently getting very poor performance from the library. I started out by serializing my objects (which are full of pointers and allocated memory, and what not), but that didn't perform at all, so I went for a more brute force approach instead. No luck there either. Essentially what I want to do in a typical case, is to send a set of indexes (4 integers) followed by an array of doubles. The arrays sizes are fixed at startup, and have a size between 10-60 kB each. There are usually many of these arrays, and the total amount of data to be communicated at the end of a calculation is of the order of 1GB. Here is my current implementation: 1) Pack the indexes into an array of 4 integers and send (or broadcast) to the receiver(s). The receiver figures out where to store the next packet based on the indexes (this takes next to no time). 2) Send the array to the receivers using: double *data = coefs->data(); world.send(who, tag, data, nCoefs); where coefs is a pointer to an Eigen2 vector, and data is a pointer to a contiguous array of doubles. I'm running the code on a big HPC cluster with individual nodes with 8 cores and 16 GB memory, all connected with Infiniband. Using this setup I achieve a maximum transfer rate of 66 MB/s doing all to one communication, which is approx. 10 times less than what I'm supposed to get. I will not even mention how long a broadcast takes, but suffice to say that it takes 20-25 times longer than doing the calculation. I get the same poor performance regardless of whether I'm communicating only over 127.0.0.1 or over the net. Since out environment is homogeneous, I have compiled the both the mpi library and my program defining the BOOST_MPI_HOMOGENEOUS macro. I will try to batch more packages into larger units, but earlier experiences (with basic MPI) has shown that with 65 kB arrays, transfer rates of 1 GB/s are possible over our Infiniband switch. Asynchronous transfer is an option, but that complicates the load balancing algorithms to a point where I really don't want to go unless under gun point. Any suggestions? Best regards, -jonas- -- ________________________________________________________________________ Dr. Jonas Jusélius Centre for Theoretical and E-mail : jonas.juselius(a)uit.no Computational Chemistry Telephone : +47 77644079 Department of Chemistry Fax : +47 77644765 University of Tromsø Mobile ph.: +47 47419869 N-9037 Tromsø, NORWAY http://jonas.iki.fi _______________________________________________________________________ [ PGP key : keyserver or http://jonas.iki.fi/pubkey.asc ] [ Fingerprint: 2516 A57A 3012 7962 287D B66E C1A9 157F 0A59 7A66 ]

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