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OpenMP and Boost - can they be used together?
by Max S. Kaznady 16 Sep '10

16 Sep '10

Hello, I wrote a simple parallel program which computes the sum of elements across a matrix using Boost. When I use OpenMP, the program runs give different sums. When I use just simple arrays like double array[N][N], instead of boost::numeric::ublas::matrix<double>, the code work just fine and as expected. Does anyone know what is going on? It looks like the score function is not being modified properly, because Boost array returns just fine. The function compute_score() creates a matrix and computes the sum of its elements in parallel, copying the result to matrix temp and then printing temp, to make sure that the results can be copied in parallel too. The function is run infinitely many times, and if its return values differ then the program exits. [code] #include <iostream> #include <omp.h> #include <boost/numeric/ublas/io.hpp> #include <boost/numeric/ublas/matrix.hpp> #define ENABLE_OPENMP_SCORE 1 #define N 10 #define NUMTHREADS 2 using std::cout; using std::endl; using boost::numeric::ublas::matrix; double compute_score() { matrix<double> data1(N, N); for (unsigned i = 0; i < N; ++i) for (unsigned j = 0; j < N; ++j) data1(i, j) = i * N + j; double sc = 0.0; unsigned i, j; matrix<double> temp(N, N); #pragma omp parallel \ shared(sc,temp) \ private(i,j) \ if (ENABLE_OPENMP_SCORE) { omp_set_num_threads(NUMTHREADS); #pragma omp master sc = 0.0; #pragma omp for reduction(+:sc) schedule(static) collapse(2) nowait for (i = 0; i < N; ++i) { for (j = 0; j < N; ++j) { temp(i, j) = data1(i, j); sc += data1(i, j); } } } cout << temp << endl; return sc; } int main(void) { double oldval = compute_score(), newval; cout.precision(32); cout << "--" << endl; while (1) { newval = compute_score(); cout << "--" << endl; if (newval != oldval) { cout << " newval - oldval = diff, " << newval << " - " << oldval << " = " << newval - oldval << endl; exit(1); } oldval = newval; } return 0; } [/code] This problem is driving me insane... the code is really simple, but for some reason after using Boost it does not function as expected. Cheers, Max

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[Serialization] Encrypting an xml archive
by Sean Farrow 16 Sep '10

16 Sep '10

Hi: Has anyone had the need to encrypt an xml or binary archive? If so what is the best way of going about it? Do I need to create a totally new archive class, or can I just derive from another one of boosts archive classes, if yes which methods should be overridden? Thanks for any pointers Regards Sean.

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Editable XML Serialization
by Anne van Rossum 16 Sep '10

16 Sep '10

Dear list members, I guess it's one of the hardest search terms around but I would like to know if there is any editable XML serialization provided by Boost or other C++ libraries. And I don't mean the kind of thing that requires you to go jumping around through trees, with iterators etc. I don't want to see any iterator! I really iike the XML serialization method that boost::serialization provides: //! Give boost serialization libraries access to private fields friend class boost::serialization::access; //! Tell which private fields to serialize template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & boost::serialization::make_nvp("Phase", phase); ar & boost::serialization::make_nvp("Period", period); ar & boost::serialization::make_nvp("DutyCycle", dutycycle); } Just adding this to a file, and then: xml_out << boost::serialization::make_nvp("ApplicationConfig", config); Or: xml_in >> boost::serialization::make_nvp("ApplicationConfig", config); It's awesome! I don't need to care about descending trees, etc. However, the default serialization class does not allow for different orders of the XML tags, etc. It doesn't use the "ApplicationConfig" string, but just assumes that XML tag should be there if this read operation. If you change anything in the XML file, it is likely you will get a segfault, and you won't know what is causing the problem exactly. It would be so great if there is something like this in which the XML files can actually be edited! I am almost sure that there should be something like that, but I can't find it. Thanks in advance, Anne

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ASIO Win32 Thread not terminated
by Manuel Drews 16 Sep '10

16 Sep '10

Hi all, I have a question regarding boost::asio: if I run the example boost_asio/example/http/client/async_client.cpp on a Windows 7 or Vista and set a breakpoint on the very last line (return 0;), VisualStudio tells me that (apart from the Main Thread) two Threads named Win32 Thread are still running. Since the whole ASIO code is within the try block, everything connected to the sockets should be terminated when leaving the block, right? I get this behaviour also in a custom project, where I explicitly call close on the socket. My concern is, that a project which uses a lot of socket connections will end up with a dozen or more lingering threads. How can I avoid that? Thanx in advance Manuel -- GMX DSL SOMMER-SPECIAL: Surf & Phone Flat 16.000 für nur 19,99 Euro/mtl.!* http://portal.gmx.net/de/go/dsl

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Boost.math statistical distributions - testing inverse gamma and inverse chi squared and Bayesan examples - help wanted.
by Paul A. Bristow 16 Sep '10

16 Sep '10

I am working on adding (by popular request;-) a few more statistical distributions inverse gamma and inverse chi squared are close to being done. But I would be most grateful for help with 1 A few spot test values to check that I haven't made mistakes. Ideally I'd like some very accurate values from the ultimate reference Wolfram Mathematica, or perhaps an R add-on (not in main release?). If anyone can spare a moment to evaluate a few values for me please email me privately. 2 I have some suggestions for an example of using these distribution(s), but would like others. (We like to provide a real-life example of statistics in action in our documentation). Do any you followers of the Reverend Bayes have any suggestions for examples, preferably fully worked through from raw data? Thanks Paul PS If there are other distributions for which there are 'popular requests', now is the moment to ask ;-) --- Paul A. Bristow, Prizet Farmhouse, Kendal LA8 8AB UK +44 1539 561830 07714330204 pbristow(a)hetp.u-net.com

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[asio] An error occured in asio::win_mutex.hpp
by Yasuhiko Yoshimura (informax.co.jp) 16 Sep '10

16 Sep '10

Hi ALL, I have encountered this error, and would like to program a win32 FTP client with asio lib. In asio examples I reffenrenced at the 'Services(logger program)'. Could you help me ? I appriciate any suggestion. Thank all, Yasuhiko Yoshimura (Japan) An accsess violence occured at the below ===>> point. win_mutex.hpp:line 125: ------------------------------------------------------------------------ Then variable values are: &crit_section_ 0xcdcdcdcd this 0xcdcdcdcd (boost::noncopyable_::noncopyable) // Locking must be performed in a separate function to lock() since the // compiler does not support the use of structured exceptions and C++ // exceptions in the same function. int do_lock() { __try { ===>> ::EnterCriticalSection(&crit_section_); } __except(GetExceptionCode() == STATUS_INVALID_HANDLE || GetExceptionCode() == STATUS_NO_MEMORY ? EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH) { if (GetExceptionCode() == STATUS_NO_MEMORY) return ERROR_OUTOFMEMORY; return ERROR_INVALID_HANDLE; } return 0; } ------------------------------------------------------------------------ Here are my codes below. And error point was ===>> ------------------------------------------------------------------------ using boost::asio::ip::tcp; class ftp_client_dtp : public boost::enable_shared_from_this<ftp_client_dtp> { public: typedef boost::shared_ptr<ftp_client_dtp> pointer; static pointer create(boost::asio::io_service& io_service) { return pointer(new ftp_client_dtp(io_service)); } tcp::socket& socket() { return *work_socket_; } ... void start() { work_thread_.reset(new boost::thread( boost::bind(&boost::asio::io_service::run, &work_io_service_))); // Start an asynchronous resolve to translate the server and service names // into a list of endpoints. tcp::resolver::query query(sip_, sport_); work_resolver_->async_resolve(query, boost::bind(&ftp_client_dtp::handle_resolve, shared_from_this(), boost::asio::placeholders::error, boost::asio::placeholders::iterator)); } void close() { work_io_service_.post(boost::bind(&ftp_client_dtp::do_close, shared_from_this())); } ftp_client_dtp(boost::asio::io_service& io_service) : work_io_service_(), work_resolver_(new boost::asio::ip::tcp::resolver(work_io_service_)), work_socket_(new boost::asio::ip::tcp::socket(work_io_service_)) ===>> { } ~ftp_client_dtp() { work_.reset(); if (work_thread_) work_thread_->join(); } private: std::ofstream f; void handle_resolve(const boost::system::error_code& err, tcp::resolver::iterator endpoint_iterator) { ... } void handle_connect(const boost::system::error_code& err, tcp::resolver::iterator endpoint_iterator) { ... } void handle_read_content(const boost::system::error_code& err) { ... } void do_close() { work_socket_->close(); } std::string sip_, sport_, scurrentpath_, sfilename_; boost::asio::streambuf request_; boost::asio::streambuf response_; boost::scoped_ptr<boost::asio::ip::tcp::resolver> work_resolver_; boost::scoped_ptr<boost::asio::ip::tcp::socket> work_socket_; boost::asio::io_service work_io_service_; boost::scoped_ptr<boost::asio::io_service::work> work_; boost::scoped_ptr<boost::thread> work_thread_; }; ftp_client_dtp::pointer new_connection_; new_connection_ = ftp_client_dtp::create(io_service_); new_connection_->start(); ------------------------------------------------------------------------ Thank all, Yasuhiko Yoshimura (Japan)

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upgrade_to_unique_lock doesn't compile with vc2010
by Braden McDaniel 16 Sep '10

16 Sep '10

Using Boost 1.43, this program: # include <boost/thread.hpp> int main() { boost::shared_mutex mutex; boost::upgrade_lock<boost::shared_mutex> lock(mutex); boost::upgrade_to_unique_lock<boost::shared_mutex> write_lock(lock); } ... produces this error when compiled with Visual C++ 2010: C:\Users\braden>cl /I include/boost-1_43 /MD /EHsc upgrade_to_unique_lock_test.cpp Microsoft (R) C/C++ Optimizing Compiler Version 16.00.30319.01 for x64 Copyright (C) Microsoft Corporation. All rights reserved. upgrade_to_unique_lock_test.cpp include/boost-1_43\boost/thread/locks.hpp(823) : error C2679: binary '=' : no operator found which takes a right-hand operand of type 'boost::unique_lock<Mutex>' (or there is no acceptable conversion) with [ Mutex=boost::shared_mutex ] include/boost-1_43\boost/thread/locks.hpp(659): could be 'boost::upgrade_lock<Mutex> &boost::upgrade_lock<Mutex>::operator =(boost::upgrade_lock<Mutex>&)' with [ Mutex=boost::shared_mutex ] include/boost-1_43\boost/thread/locks.hpp(710): or 'boost::upgrade_lock<Mutex> &boost::upgrade_lock<Mutex>::operator =(boost::detail::thread_move_t<T>)' with [ Mutex=boost::shared_mutex, T=boost::upgrade_lock<boost::shared_mutex> ] include/boost-1_43\boost/thread/locks.hpp(717): or 'boost::upgrade_lock<Mutex> &boost::upgrade_lock<Mutex>::operator =(boost::detail::thread_move_t<T>)' with [ Mutex=boost::shared_mutex, T=boost::unique_lock<boost::shared_mutex> ] while trying to match the argument list '(boost::upgrade_lock<Mutex>, boost::unique_lock<Mutex>)' with [ Mutex=boost::shared_mutex ] include/boost-1_43\boost/thread/locks.hpp(820) : while compiling class template member function 'boost::upgrade_to_unique_lock<Mutex>::~upgrade_to_unique_lock(void)' with [ Mutex=boost::shared_mutex ] upgrade_to_unique_lock_test.cpp(7) : see reference to class template instantiation 'boost::upgrade_to_unique_lock<Mutex>' being compiled with [ Mutex=boost::shared_mutex ] I've searched a bit for previous reports of this sort of thing and I haven't found any. Hopefully that means I'm just doing something wrong. -- Braden McDaniel <braden(a)endoframe.com>

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selective enabling/disabling of BOOST_AUTO_TEST_CASE
by Suresh Kumar 16 Sep '10

16 Sep '10

Hi I have several tests in my unit test file each of them uniquely named using the function BOOST_AUTO_TEST_CASE. I may not need to run all of them always and as of now what I do is to comment out the tests which I dont want to run. Instead of commenting out code, is there any other way I can selectively enable or disable tests if i have created tests with BOOST_AUTO_TEST_CASE. thanks suresh -- R Suresh Kumar, http://www.ee.ucr.edu/~sramachandranna -- Dhyaana–moolam Guror murtih Puja-moolam Guroh padam Mantra – moolam Guror vakyam Moksha – moolam Guroh krpa.

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[Parameter] abstract base class
by Noah Roberts 15 Sep '10

15 Sep '10

I have a design in which I must inherit from a class with a whole lot of construction parameters. I need to have a pure virtual function in the class that inherits from this thing and is then provided by subclasses. Since the classes in question must all accept this huge list of construction parameters I would like to use named parameters. Unfortunately there's a problem caused by the attempt to create a function pointer declaration that takes the base class by value. I don't really understand why this is going on. Instead of just calling the base's constructor directly, the BOOST_PARAMETER_CONSTRUCTOR macro creates a type resolution instantiation with this: boost::parameter::aux::unaryfunptr_arg_type< void(*)(B) >::type 'B' being the base class. This explodes if B is an abstract class. Both g++ 3.4.5 (mingw) and VS2010 hate this line. Before I go about attempting to devise a workaround, what is the purpose of this strange bit of code? Why not just use 'B' directly?? The type resolution metafunction simply returns the 'B' place argument as its type anyway... I note some weird workaround code for ancient versions of MSVC but they seem to be created to make this type resolution thing work, not because 'B' is not known or something. However, I figure the people who wrote this library are smarter and more knowlegeable than I so the fact that I see no need for this code is probably my problem and not a reflection of it being unnecessary. -- http://crazyeddiecpp.blogspot.com/

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Read from serial devices on USB
by Alejandro Martínez 15 Sep '10

15 Sep '10

Hi, I'm trying to communicate with a usb serial device plugged to a USB port. I've seen some examples with boost::asio and connecting to ie: /dev/ttyUSB0 for linux, or COM1 for windows etc. But i need something more robust and multiplatform. Like listing all the available devices and choosing by looking at the vendor id, or device id or something like that. How can i do that? Can this same approach be used later for say... bluetooth serial devices? How? Thank you all in advance. Alejandro

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