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[BGL] Auto Connect vertexes by predicate?
by arm2arm 09 May '09

09 May '09

Hello, Are there ways to generate Graph with edges by the user defined function? Should I generate Vertex relations by hand then put it in to Graph? I would like to feed graph by points 3d and each point is linked to its closest neighbor by distance. Then as a next step I would like to dig in the graph the sub-graphs with the given linking length. My Data structure is following: _____________________ class CCoord { public: CCoord(){}; CCoord(int id_,MyFloat x_,MyFloat y_,MyFloat z_, MyFloat w_=0): id(id_), x(x_), y(y_), z(z_), w(w_){ if(w==0.0) w=sqrt(x*x+y*y+z*z); }; MyFloat x, y, z; int id; MyFloat w; } typedef std::vector<CCoord> typeVecData; typedef adjacency_list < vecS, vecS, undirectedS, no_property, property < edge_weight_t, MyFloat > > Graph; typedef graph_traits < Graph >::edge_descriptor Edge; typedef graph_traits < Graph >::vertex_descriptor Vertex; typedef std::pair<int, int> E; typeVecData data(num_nodes); srand(0); generate(data.begin(),data.end(),gencoord); typedef std::pair<int, int> Edge; Graph G(5); add_edge(0, 2, G);//how to apply relation function? ________________________________________________ What is the correst way to implement this algorithm using BGL? Thank you beforehand. Arman -- View this message in context: http://www.nabble.com/-BGL--Auto-Connect-vertexes-by-predicate--tp23451992p… Sent from the Boost - Users mailing list archive at Nabble.com.

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Re: [Boost-users] [asio] sync receive_from with timeout
by Michael Dehmlow 09 May '09

09 May '09

Ha this is exactly the problem I ran into not two days ago I agree it would be nice if there was a timeout for the library: I used to following: //Oh throw a sleep in there: while(!timeout.elapsed()) { boost::system::error_code ec; boost::asio::socket_base::non_blocking_io command(true); socket.io_control(command); bytesRead = _socket->read_some(boost::asio::buffer(data, dataBufferSize), ec); if(error&&boost::asio::error::would_block!=error) { //there is some other error the client has disconnected; } else { //I must have got some data or theres no data yet check bytesRead for that } boost::this_thread::sleep( boost::posix_time::milliseconds(100)); } No extra threads necessary. Stephan Menzel-3 wrote: > > Is the subject Jehova enough for you? ;-) > > Great. > > Well, I haven't raised the subject so far but I'd certainly like to do so > now. For years now I am not only a user but also an admirer of boost asio. > Something that has always puzzled me however is, why a timeout > functionality which is something very common and essential for sync IO > just doesn't seem to be there. > > I think there are cases where syncronous IO is a better way to go and no > async approach is sensible. In my case this is a collection of static > functions that do UDP communication and therefore have to be sync because > I just want them to be able to return and throw exceptions and be able to > be called from anyone at any time. > > As always when I stumble across the asio/timeout problem I start googling > around. When people raise the topic here they are usually pointed to an > answer Chris Kohlhoff gave to someone asking that: > > http://lists.boost.org/Archives/boost/2007/04/120339.php > > ... which is good for tcp and works alright even though in my opinion it > leaves the question why it has to be so compilicated to do something so > basic. IMHO sync IO is all but pointless without a timeout. > > Anyway, I started to turn this into a UDP version and ended up with > something very similar: > > inline void set_result(boost::optional<boost::system::error_code>* a, > boost::system::error_code b) { > a->reset(b); > }; > > template <typename MutableBufferSequence> > void udp_read_with_timeout(boost::asio::ip::udp::socket& sock, int tmo, > boost::asio::ip::udp::endpoint &endpoint, const MutableBufferSequence& > buffers) { > > boost::optional<boost::system::error_code> timer_result; > boost::asio::deadline_timer timer(sock.io_service()); > timer.expires_from_now(boost::posix_time::seconds(tmo)); > timer.async_wait(boost::bind(set_result, &timer_result, _1)); > > boost::optional<boost::system::error_code> read_result; > sock.async_receive_from(buffers, endpoint, boost::bind(set_result, > &read_result, _1)); > > sock.io_service().reset(); > while (sock.io_service().run_one()) { > if (read_result) > timer.cancel(); > else if (timer_result) > sock.cancel(); > } > > if (*read_result) > throw boost::system::system_error(*read_result); > }; > > > So now I started to go ahead with that but I had to notice two things. > First, the performance impact is massive to a point that forces me to > reconsider. Second, when I use that in a multithreaded environment the > whole thing seems to block in some threads randomly. I have made test > program where I have multiple threads using that method, just sending an > UDP request to a server and waiting for an answer using this function. In > one thread everything is slow but continously running. In more than one > thread it blocks for up to 5 or 6 seconds every few (10-20) runs for no > visible reason. In my scenario all those threads share a socket protected > by a mutex so if one of them blocks all will be halted. > > So I come to think this is not a good way to handle the problem. Does > anyone have some thoughts on that? May this be a bug in asio (1.38) or > perhaps in my function? Or is there a better way to do sync UDP IO with a > timeout functionality? > > Cheers... > > Stephan > > > > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users > > -- View this message in context: http://www.nabble.com/-asio--sync-receive_from-with-timeout-tp22326399p2233… Sent from the Boost - Users mailing list archive at Nabble.com.

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is this possible with tuples in c++0x ?
by Germán Diago 09 May '09

09 May '09

template <typename... Types> class tuple ... { template <typename N> auto operator[](std::size_t n = N) -> constexpr decltype(get<N>(*this)) { return get<N>(*this); } }; If this is possible, you could do (and it would be way more natural than get<3>(t)): tuple<int, float, float, string, mytype> t; t[3] = "hello"; But I feel this is not legal because of parameter std::size_t :(.

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more than one template with automated registration
by tang10＠llnl.gov 08 May '09

08 May '09

Is there a macro similar to BOOST_AUTO_TEST_CASE_TEMPLATE for this: template< typename Value, typename Field > void testFunction() { ... }; Thanks, Nu Ai.

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boost.python error while ./bjam install
by Aamir Ahmed Khan 08 May '09

08 May '09

I am compiling boost.python libraries by following the procedure given at http://www.boost.org/doc/libs/1_39_0/more/getting_started/unix-variants.htm… I first configure the build and installation using bootstrap.sh script $ ./bootstrap.sh --with-python=/usr/bin/python2.5 --with-libraries=python --prefix=~/work/boost/setup/boost_1_39_0/mybuild Here are the contents of project-config.jam fie as generated by the script. # Boost.Build Configuration > # Automatically generated by bootstrap.sh > > import option ; > import feature ; > > # Compiler configuration. This definition will be used unless > # you already have defined some toolsets in your user-config.jam > # file. > if ! gcc in [ feature.values <toolset> ] > { > using gcc ; > } > > project : default-build <toolset>gcc ; > > # Python configuration > using python : 2.5 : /usr ; > > # List of --with-<library> and --without-<library> > # options. If left empty, all libraries will be built. > # Options specified on the command line completely > # override this variable. > libraries = --with-python ; > > # These settings are equivivalent to corresponding command-line > # options. > option.set prefix : ~/work/boost/setup/boost_1_39_0/mybuild ; > option.set exec-prefix : ~/work/boost/setup/boost_1_39_0/mybuild ; > option.set libdir : /lib ; > option.set includedir : ~/work/boost/setup/boost_1_39_0/mybuild/include > ; > The output of bootstrap.sh script instructs me to run ./bjam to build while instructions at the above link say to run ./bjam install Anyways, I tried both the options but every time I get the same error > Class top-level-target already defined > Aborted > I searched the forums, but this error seems to never be discussed. I am stuck, please help! Best regards, Aamir Ahmed Khan

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Statically linking libstdc++.so.6 and boost
by Michael Dehmlow 08 May '09

08 May '09

I have a rather interesting situation and I'm wondering if any one has some ideas. I am building a linux shared library which uses boost and xerces, I have an application which I compile and run fine using gcc 4.1 which uses stdlibc++.so.6. I also have a requirement to create an interface for Labview 8.6 which is built using gcc 3.3 which uses stdlibc++.so.5. After some investigation I found that Labview would crash on any std::string concatenation because it was dynamically using the old stdlib(5). In a simplified test tool I statically linked the stdc++ lib using this really great page: http://www.trilithium.com/johan/2005/06/static-libstdc/ Everything worked great until I started adding my cots (boost and xerces) into the mix. For xerces I simply modified the xerces make file to statically link stdlib and (using gdb was able determine that) I get past all my xerces calls. However when I make call to boost lexical cast it still tries to use the dynamic std library 5: #0 0x00cab1a7 in std::string::data () from /usr/lib/libstdc++.so.5 #1 0x0362b479 in boost::detail::lexical_cast<int, std::string, false, char> (arg=@0x0, buf=0x0, src_len=0) at /usr/include/boost/boost_1_38_0/boost/lexical_cast.hpp:1149 #2 0x0362b500 in boost::detail::lexical_cast<int, std::string, false, char> (arg=Cannot access memory at address 0x8 ) at /usr/include/boost/boost_1_38_0/boost/lexical_cast.hpp:1159 Above is the stack trace immediately preceding my segmentation fault. One: I thought that lexical cast was built into hpp files and was compiled at my application compile time is that correct? Two: does any one know how to make the symbols from a .a (static library) file look in the encapsulating so's symbol table before the applications symbol table? Or can anyone point me at some information on symbol lookup precedence. Three: I'm considering including all of the generated object files from the included boost .a files in my make file rather than including the staticboost libraries themselves. Seem like a good idea? Any pitfalls? Four: any other Ideas? Below is the meat of my make file: g++ -g -static-libgcc -nodefaultlibs -fPIC -shared -fno-gnu-linker -Wl,-soname,libEXPO.so -o libEXPO.so ${APIOBJECTS} ${DETAILOBJECTS} ${OBJECTS} -L. -L../../../utl/CommonObjects/XML/ -L../../../utl/CommonObjects/Exceptions ${COTS_EXPO_BOOST_LIBDIR_38}/libboost_thread-gcc41-mt-1_38.a ${COTS_EXPO_BOOST_LIBDIR_38}/libboost_filesystem-gcc41-mt-1_38.a ${COTS_EXPO_BOOST_LIBDIR_38}/libboost_system-gcc41-mt-1_38.a ${COTS_EXPO_BOOST_LIBDIR_38}/libboost_regex-gcc41-mt-1_38.a ${COTS_EXPO_BOOST_LIBDIR_38}/libboost_date_time-gcc41-mt-1_38.a ./libxerces-c.so.26 -lXML -lExceptions -lc /lib/libpthread.so. -- View this message in context: http://www.nabble.com/Statically-linking-libstdc%2B%2B.so.6-and-boost-tp234… Sent from the Boost - Users mailing list archive at Nabble.com.

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[test] Crash when running my unit tests
by Christian Henning 08 May '09

08 May '09

Hi there, when I try to run my tests the unit testing framework seems to crash for no apparent reason. The point it's crashing is in unit_test_suite.ipp[263]. It seems to crash before entering the first test. The c++ runtime at this points tries to delete the memory of a string which triggers the assertion. _ASSERTE(_BLOCK_TYPE_IS_VALID(pHead->nBlockUse)); Here is my scenario: Everything used to run just fine before I added a new file containing more tests. Meaning all of my tests are scattered around a couple of files ( 20 files ) which sum up to about 120 tests. I don't think that this usage is anything but exceptional. When I exclude the new test file the tests are running fine. When including the new test file it crashes. I'm running the boost trunk on a windows xp using MSVC 2005. Anyone any idea what I can do about this? My code is available here: http://gil-contributions.googlecode.com/svn/trunk/ The tests are here: http://gil-contributions.googlecode.com/svn/trunk/gil_2/libs/gil/io_new/tes… Any help is more than welcome. Thanks ahead, Christian

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Unique parameter values for interfaces
by Ryan McConnehey 08 May '09

08 May '09

I'm currently trying to fortify my class api by "make interfaces easy to use correctly and hard to use incorrectly". I have a class as follows. class api { api(ConfigName const& configName_, PathName const& pathName_) : m_ConfigName(configName_.value) , m_PathName(pathName_.value) {} std::string m_ConfigName; std::string m_PathName; }; Both ConfigName and PathName are typedef to a template structure as follows. template<typename S> struct ParameterValue { ParameterValue(S value_) : value(value_) {} S value }; typedef ParameterValue<std::string> ConfigName; typedef ParameterValue<std::string> PathName; I realized later that this method doesn't prevent the swapping of a ConfigName with a PathName parameter. Since both parameters are typedef to the same "type" of ParameterValue they're interchangeable. Is there a boost class, library or C++ idiom that would provide what I'm looking for? Since I'm going to be using this concept for other classes I build, I'd like something that would easily create parameter classes to use but not be interchangeable with other classes of the same type. I know that I could do this with a macro but I'm leaving that for a last resort. Ryan

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boost mpi + pointer to polymorphic class
by Michael Levenhagen 08 May '09

08 May '09

Hello, I'm having a problem using boost::mpi::communicator::isend(). The problem is that it appears isend can't serialize via a pointer to the base of a polymorphic class. I'm using boost::serialization extensively to archive and I believe serializing via a pointer to a base class works when archiving. This is what I'm trying: class Event { public: virtual ~Event(); }; class Der1Event : Event { }; class Der2Event: Der1Event { }; Der2Event* d2 = new Der2Event; Der1Event* d1 = static_cast<Der1Event*>(d2) boost::mpi::communicator world; world.isend( 0, 0, d1 ); My program faults when calling isend(). I know my example is missing details such as serialization code but in principle should this work? BTW the following works. world.isend( 0, 0, d2 ) thanks Mike

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Steps to build boost library for 64 bit platform.
by Jaiswal, Usha [OS-IE] 08 May '09

08 May '09

Hi, Can any one tell me the steps to build boost library for 64 bit platform, please reply ASAP. Thanks a lot. -Usha.

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