August 2008 - Boost-users - lists.preview.boost.org

[spirit] repeat_p parameters
by piotr270977＠interia.pl 13 Aug '08

13 Aug '08

Hi All I wonder about expression repeat_p parameter. int c; c=12; repeat_p(boost::ref(c)) is OK but what about repeat_p(boost::ref(c) - 1 ) ??? (compiling but not working correctly) The only solution I have found is int c, c1; c=12; c1 = c-1; repeat_p(boost::ref(c1)) Is it possible to insert an expression in repeat_p without c1 extra variable ? ---------------------------------------------------------------------- Podbij Dziki Zachod, wygraj laptopa lub iPoda >> http://link.interia.pl/f1ede

1 0

boost::math::tools ?
by Jesse Perla 13 Aug '08

13 Aug '08

Poking around in the headers of 1.35 I found code: polynomial.hpp, roots, series, minima, remez, and a few others I would love to use. However, I don't see any mention of these in the boost::math documentation. Do these work? Are they kept up to date? Any reason why they are not mentioned in the docs or did I just miss it? Thanks, Jesse

3 2

[Building] 64 bit on Linux
by Pearl Rothman 13 Aug '08

13 Aug '08

How can I build 64 bit boost libraries on Linux, preferably using gcc?

3 2

Re: [Boost-users] MS SDK 2003 Compiler Configuration
by Bob Monat 13 Aug '08

13 Aug '08

2 1

Re: [Boost-users] Multi-index container (Modifying non-unique key in the container)
by JOAQUIN M. LOPEZ MUÑOZ 12 Aug '08

12 Aug '08

Hi Ramesh, ________________________________ De: boost-users-bounces(a)lists.boost.org [boost-users-bounces(a)lists.boost.org] En nombre de Ramesh [rramesh1(a)gmail.com] Enviado el: martes, 12 de agosto de 2008 7:40 Para: boost-users(a)lists.boost.org Asunto: [Boost-users] Multi-index container (Modifying non-unique key in the container) > > Hi. > > I am using boost multi-index container for storing objects of type class A, in the class key1 & > Key 3 are unique and key2 is non-unique. I try to insert objects of type A and it works fine. > No issues. > > At some point after the insertion, I wish to modify the key2 to 20 in the container. Can I do this > with modify? If yes How do I define the iterator (since I need to do a find based on key1 but > modify key2 in the container) You have two options: 1. Use modify(), which is passed the entire element rather than the key, and modify key2 at your pleasure. 2. Project the key1-iterator to a key2-iterator using the projection facilities: http://www.boost.org/libs/multi_index/doc/tutorial/basics.html#projection and then use modify_key() with the key2-iterator. BTW, I've noticed that you're wrapping the A objects into a DataMap class that, oddily enough, replicates the key1, key2 and key3 members. Why aren't you using A members directly thus disposing of the DataMap wrapper? Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

2 1

sorting a ublas matrix
by Ed 12 Aug '08

12 Aug '08

#include <boost/numeric/ublas/matrix.hpp> #include <boost/numeric/ublas/io.hpp> using namespace boost::numeric::ublas; matrix<MyObject> m_MyObjects(nRows, nCols); I have a ublas matrix of objects as declared above... Is there a way within the Boost lib (i.e. something I don't have to write much custom code to use) that I can use to sort the matrix by a value of one of the data members of MyObject? For example If class MyObject { int thisOne; } and m_MyObjects(0,0).thisOne = 1; m_MyObjects(1,0).thisOne = 0; m_MyObjects(0,1).thisOne = 4; m_MyObjects(1,1).thisOne = 2; It will sort the matrix so that m_MyObjects(0,0).thisOne = 0; m_MyObjects(1,0).thisOne = 1; m_MyObjects(0,1).thisOne = 2; m_MyObjects(1,1).thisOne = 4; Ed

2 1

boost::serialization xml_archive usage
by Markus Schwarzenberg 12 Aug '08

12 Aug '08

Hi, i just recently startet to dip into boost::serialization. In the examples directory, there is demo.cpp, in which text_archive is used. From my understanding of the tutorial ("In addition to text archives, the library includes archive class for native binary data and xml formatted data Interfaces to all archive classes are all identical.") it should be possible to switch from text_archive to xml_archive by just replacing text_[io]archive by xml_[io]archive and include the required header files. However, when I do this, I'm getting lots of compiler error messages like (Linux, gcc-4.1.2, boost-1.35.0) /usr/include/boost-1_35/boost/archive/basic_xml_oarchive.hpp: In member function 'void boost::archive::basic_xml_oarchive<Archive>::save_override(T&, int) [with T = const bus_schedule, Archive = boost::archive::xml_oarchive]': /usr/include/boost-1_35/boost/archive/detail/interface_oarchive.hpp:64: instantiated from 'Archive& boost::archive::detail::interface_oarchive<Archive>::operator<<(T&) [with T = const bus_schedule, Archive = boost::archive::xml_oarchive]' demo-using-xml.cpp:286: instantiated from here /usr/include/boost-1_35/boost/archive/basic_xml_oarchive.hpp:88: error: no matching function for call to 'assertion_failed(mpl_::failed************ boost::serialization::is_wrapper<const bus_schedule>::************)' /usr/include/boost-1_35/boost/archive/basic_xml_iarchive.hpp: In member function 'void boost::archive::basic_xml_iarchive<Archive>::load_override(T&, int) [with T = bus_schedule, Archive = boost::archive::xml_iarchive]': /usr/include/boost-1_35/boost/archive/xml_iarchive.hpp:74: instantiated from 'void boost::archive::xml_iarchive_impl<Archive>::load_override(T&, int) [with T = bus_schedule, Archive = boost::archive::xml_iarchive]' /usr/include/boost-1_35/boost/archive/detail/interface_iarchive.hpp:63: instantiated from 'Archive& boost::archive::detail::interface_iarchive<Archive>::operator>>(T&) [with T = bus_schedule, Archive = boost::archive::xml_iarchive]' demo-using-xml.cpp:297: instantiated from here The original demo.cpp however compiles fine. The difference to the version using xml_archive is just: --- demo.cpp 2008-08-11 18:06:45.394403000 +0200 +++ demo-using-xml.cpp 2008-08-12 07:33:33.147259000 +0200 @@ -14,8 +14,8 @@ #include <boost/archive/tmpdir.hpp> -#include <boost/archive/text_iarchive.hpp> -#include <boost/archive/text_oarchive.hpp> +#include <boost/archive/xml_iarchive.hpp> +#include <boost/archive/xml_oarchive.hpp> #include <boost/serialization/base_object.hpp> #include <boost/serialization/utility.hpp> @@ -282,7 +282,7 @@ void save_schedule(const bus_schedule &s, const char * filename){ // make an archive std::ofstream ofs(filename); - boost::archive::text_oarchive oa(ofs); + boost::archive::xml_oarchive oa(ofs); oa << s; } @@ -291,7 +291,7 @@ { // open the archive std::ifstream ifs(filename); - boost::archive::text_iarchive ia(ifs); + boost::archive::xml_iarchive ia(ifs); // restore the schedule from the archive ia >> s; @@ -352,7 +352,7 @@ std::cout << original_schedule; std::string filename(boost::archive::tmpdir()); - filename += "/demofile.txt"; + filename += "/demofile.xml"; // save the schedule save_schedule(original_schedule, filename.c_str()); What am I doing wrong? Thanks, Markus Schwarzenberg

2 1

[Boost.Thread] Scheduling
by Ruediger Berlich 12 Aug '08

12 Aug '08

Hi there, at the end of this mail is a small program that starts three threads out of a fourth one ("thread4"). thread1, 2 and 3 are not allowed to start execution before a certain condition is met (here: go_ is set to true and the threads are notified of the changed condition). The threads increment a variable. Once this variable has reached a threshold (here: 10), execution is supposed to stop. This is done by calling the interrupt() function on each thread, which in turn catch the corresponding exception and act on it. All this seems to work nicely, except for the fact that the "master thread" (thread4 in this example) does not seem to get any processing time over a long period. Hence thread 1,2 and 3 count to a very high number before the stop condition is met. Here is the output of the program: Starting threads Going to sleep for 2 seconds in startAndStopThreads() Hello world Nr. 0 from thread 1 Hello world Nr. 1 from thread 2 [...] Hello world Nr. 6167 from thread 2 Hello world Nr. 6168 from thread 2 Sending interrupt Received interrupt in thread 3 Received interrupt in thread 1 Received interrupt in thread 2 Done ... Occasionally the counting can go on up to a few hundred thousand. This is on a single-processor machine with OpenSUSE 11/64 bit, g++ 4.3.1 and a recent trunk version of Boost 1.36 . The situation is much better on a four-processor system with the same operating system - the counter typically reaches only a few hundred there, presumably as thread4 gets access to a time slice more quickly (but why isn't it running permanently on a four processor machine - there are only 4 active threads ?). Is there anything that can be done to improve the time slices allocated to thread4 ? I am already calling the yield() function in thread1, 2 and 3. Thanks and Best Regards, Ruediger /*********************************************************************/ #include <iostream> #include <boost/cstdint.hpp> #include <boost/bind.hpp> #include <boost/exception.hpp> #include <boost/thread/mutex.hpp> #include <boost/thread/condition.hpp> #include <boost/thread/condition_variable.hpp> #include <boost/thread/thread.hpp> #include <boost/date_time.hpp> using namespace std; class test { public: test() :jointData_(0), MAXJOINTDATA(10), go_(false), thread1(boost::bind(&test::sayHello, this, 1)), thread2(boost::bind(&test::sayHello, this, 2)), thread3(boost::bind(&test::sayHello, this, 3)) { /* nothing */ } void startAndStopThreads(){ std::cout << "Going to sleep for 2 seconds in startAndStopThreads()" << std::endl; boost::this_thread::sleep(boost::posix_time::seconds(2)); boost::unique_lock<boost::mutex> lock(helloMutex_); go_=true; lock.unlock(); readyToGo_.notify_all(); while(true){ boost::unique_lock<boost::mutex> lock2(helloMutex_); if(jointData_ >= MAXJOINTDATA){ go_=false; std::cout << "Sending interrupt" << std::endl; thread1.interrupt(); thread2.interrupt(); thread3.interrupt(); break; } } thread1.join(); thread2.join(); thread3.join(); } void sayHello(const uint16_t threadNumber){ while(true){ boost::unique_lock<boost::mutex> lock(helloMutex_); while(!go_) { try{ readyToGo_.wait(lock); } catch(boost::thread_interrupted&){ std::cout << "Received interrupt in thread " << threadNumber << std::endl; return; } } std::cout << "Hello world Nr. " << jointData_++ << " from thread " << threadNumber << std::endl; boost::this_thread::yield(); } } private: volatile uint32_t jointData_; const uint32_t MAXJOINTDATA; bool go_; boost::mutex helloMutex_; boost::condition_variable readyToGo_; boost::thread thread1, thread2, thread3; }; main(){ test Test; std::cout << "Starting threads" << std::endl; // Test.startAndStopThreads(); // This doesn't make a difference boost::thread thread4(boost::bind(&test::startAndStopThreads,&Test)); thread4.join(); std::cout << "Done ..." << std::endl; }

4 10

mpl tuple / pair
by Hicham Mouline 12 Aug '08

12 Aug '08

hello, as much as boost::tuple extends the idea of std::pair from 2 to n, what would be the type that extends boost::mpl::pair to n? mpl::vector? rds,

2 1

Re: [Boost-users] boost lapack bindings
by Jesse Perla 12 Aug '08

12 Aug '08

Omar: I am going through the exact same thing right now. See the thread: http://lists.boost.org/MailArchives/ublas/2008/08/2906.php At one point I posted the steps I used with the Intel Compiler in visual studio and Intel MKL's lapack. (I think that the ublas group is better for these topics). -Jesse

1 0