- Boost-users - lists.boost.org

[graph] dijkstra additional constrains that will stop the search (ex. distance from source)
by The Maschine 16 Apr '13

16 Apr '13

Hi all, I've been reading around the list (Ill post examples below) but I dont really know how to implement the thing below. I want the search to be able to stop based on some "value" or "result of a function". For example, every node has a "length" value in a custom "struct VertexProperties". How is it possible for dijkstra_shortest_paths to only consider nodes that are inside a radius from the source? Everything else should be considered as 'unconnected'. I have checked a couple of posts form the list but I dont know what do really do. (function property map, exceptions in visitors etc) http://thread.gmane.org/gmane.comp.lib.boost.user/54392/focus=54397 http://thread.gmane.org/gmane.comp.lib.boost.user/72072/focus=72074 http://thread.gmane.org/gmane.comp.lib.boost.user/73358/focus=73384 I havent found any example or source online that deals with something similar. Any ideas? code example or tutorials? Best, Tasos my graph for example: struct VertexProperties { double m_length; int m_ref; }; typedef double Weight; typedef boost::property<boost::edge_weight_t, double> EdgeWeightProperty; typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, VertexProperties, EdgeWeightProperty> unGraph;

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Re: [Boost-users] [Graph] dijkstra_shortest_paths: weird distance to vertex (1.79769e+308)
by The Maschine 16 Apr '13

16 Apr '13

Hi Jeremiah, How do I eliminate cases like this? (not connected vertex) For you post I think you cannot use "isnan" or "isinfinate" right? My only option is colormap or predecessors? (I havent use them yet) Best, Tasos

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boost asio daemon
by Philipp Kraus 16 Apr '13

16 Apr '13

Hello, I use boost::asio for creating a daemon, I do this: io::io_service l_ioservice; io::signal_set l_signals(l_ioservice, SIGINT, SIGTERM); l_signals.async_wait(daemonhandler); l_ioservice.run(); my daemonhandler shows: void daemonhandler( const boost::system::Error_code& err ) { if (!err) do some log } The daemon handler function is a function, that runs in a thread loop, does it? Can I create something like: void daemonhandler( const boost::system::Error_code& err ) { if (!err) do some log else do daemon work } My question is, is the daemonhandler function a function that is called only if the daemon is stopped or that is run during the daemon is active / working? Thanks Phil

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Re: [Boost-users] [CMake] [boost][b2] Differenciate 32bit and 64 bit binaries when using CMake.
by Klaim - Joël Lamotte 16 Apr '13

16 Apr '13

Júlio Hoffimann said: > > I don't know if i understood correctly, but you can set the library > directory by hand, please refer to > /usr/share/cmake-<version>/Modules/FindBoost.cmake, in particular the > variable BOOST_LIBRARYDIR. On Thu, Oct 11, 2012 at 1:29 PM, Miller, Frank <FMiller(a)sjm.com> wrote: > A simple solution would be to install only the 64bit version of boost > into a new directory and change the environment variable to point there. > Then FindBoost will only be able to see the version you want. > Thanks, this will solve my immediate problem, but it don't solve it in general. (I will use it though, so thanks) I can't guarantee where the boost libraries are installed, that's why I use FindBoost. My current understanding is that boost don't have a specific default lib dir for different address models, which is the source of the problem as FindBoost script can't rely on a protocol to find these lib files. Am I correct? Joel Lamotte

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PBGL Dijkstra's Single Source Shortest Path
by claire eisner 15 Apr '13

15 Apr '13

Is there a way to access the shortest path from source to target? The issue I am having is that only the local portions of the predecessor maps are written. Claire

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MSM: Initialize inner state machine from outer state machine
by Dan Schatzberg 15 Apr '13

15 Apr '13

Hi, I have shared data between states which are state machines themselves. I've stored the shared data in the outer state machine and wish to initialize each of the inner state machines with a reference to the shared data. Is this the "right way" to do this? How would I do this? Here's an example of what I'm doing: struct Outer_ : state_machine_def<Outer_> { int foo; struct Inner_ : state_machine_def<Inner_> { int& foo; Inner_(int& f) : foo(f) {} ... } ... } How do I get the inner state machines constructor called with data from the outer state machine? Or is this just the wrong way to do things? Thanks

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[serialization] EOF marker?
by Ramey, Larry 15 Apr '13

15 Apr '13

Is there a way to serialize an unknown number of items and then read them back? In essence, I'd like to do this: Ignore the variables being serialized, these are pointers to base classes, they go in and out just fine. try { ofstream ofs(fileName.c_str(),ios::binary); portable_binary_oarchive oa(ofs); //boost::archive::text_oarchive oa(ofs); oa<<qdc <<qdf <<qdenv <<qdmsg <<qsd <<qdfc <<qdce; } catch(boost::archive::archive_exception& ae) { cout<<ae.what(); } try { ifstream ifs(fileName.c_str(),ios::binary); portable_binary_iarchive ia(ifs); //boost::archive::text_iarchive ia(ifs); while( true ) { ia>>qdc2; cout<<qdc2->GetElementDebugType()<<endl; delete qdc2; qdc2=NULL; } } catch(boost::archive::archive_exception& ae) { cout<<ae.what(); } catch( std::exception& e) { cout<<e.what(); } What happens is that an exception gets tossed with this message: 5 2 14 1 3 18 Access violation - no RTTI data! The numbers are correct, those are the elements that got serialized. I'd like to do something like: while( ia ) { Ia>>qdc2; } But there is no () operator on an portable_binary_iarchive . I tried to do the test on the input stream, but that didn't work either. I don't know how many elements there are because I'm writing them as I go, I don't want to catch that exception as the EOF marker, because it really isn't the correct exception for that. I tried walking through the serialization code to see where it actually reads a byte stream form the file... but I'm apparently not smart enough to unravel that much templated Macro awesomeness. :) Larry E. Ramey

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Compile error in boost atomic on iOS
by Olivier Tristan 15 Apr '13

15 Apr '13

Hi Guys, I'm trying to use boost lockfree and a fixed size queue on iOS and I got some compile issue. The target is an armV7 compiled with clang in c++11 mode from Xcode 4.6 Does this ring a bell to someone ? Thanks, In file included from /usr/local/include/boost/lockfree/queue.hpp:22: In file included from /usr/local/include/boost/lockfree/detail/atomic.hpp:39: In file included from /usr/local/include/boost/atomic.hpp:12: In file included from /usr/local/include/boost/atomic/atomic.hpp:16: In file included from /usr/local/include/boost/atomic/detail/platform.hpp:37: In file included from /usr/local/include/boost/atomic/detail/gcc-armv6plus.hpp:245: /usr/local/include/boost/atomic/detail/cas32weak.hpp:892:21: error: invalid operands to binary expression ('value_type' (aka 'boost::lockfree::detail::tagged_index') and 'value_type') if (tmp != expected) { ~~~ ^ ~~~~~~~~ /usr/local/include/boost/atomic/detail/cas32weak.hpp:905:5: note: in instantiation of member function 'boost::atomics::detail::base_atomic<boost::lockfree::detail::tagged_index, void, 4, false>::compare_exchange_strong' requested here BOOST_ATOMIC_DECLARE_BASE_OPERATORS ^ /usr/local/include/boost/atomic/detail/base.hpp:44:16: note: expanded from macro 'BOOST_ATOMIC_DECLARE_BASE_OPERATORS' return compare_exchange_strong(expected, desired, order, calculate_failure_order(order)); \ ^ /usr/local/include/boost/lockfree/queue.hpp:290:31: note: in instantiation of member function 'boost::atomics::detail::base_atomic<boost::lockfree::detail::tagged_index, void, 4, false>::compare_exchange_strong' requested here tail_.compare_exchange_strong(tail, new_tail); ^ /usr/local/include/boost/lockfree/queue.hpp:261:16: note: in instantiation of function template specialization 'boost::lockfree::queue<StreamingCommand, boost::lockfree::fixed_sized<true>, boost::lockfree::capacity<1024>, boost::parameter::void_>::do_push<true>' requested here return do_push<true>(t); -- Olivier Tristan

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[preprocessor] Is there an equivalent of "delayed expansion"?
by Mostafa 15 Apr '13

15 Apr '13

Is there an equivalent in boost for delaying the expansion of a macro? For example, I want EAT to act on TSEQ2, so I have to use trick on line 4. #define TSEQ2 (w)(x)(y)(z)(a)(b)(c)(d 2) #define IDENTITY(x) x #define EAT(x) IDENTITY(IDENTITY(EAT)TSEQ2) Thanks, Mostafa

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[Graph] dijkstra_shortest_paths: weird distance to vertex (1.79769e+308)
by The Maschine 15 Apr '13

15 Apr '13

Hi all, Might be something really stupid but I cant think of a problem. (maybe its my limited experience with BGL common pitfalls) for (boost::tie(vi, vi_end) = boost::vertices(m_ugraph); vi != vi_end; ++vi) { depth += distances[*vi]; ..... path to:51886 distance to that node: 16.2 current total: 437998 path to:51887 distance to that node: 16.3 current total: 438014 path to:51888 distance to that node: 16.2 current total: 438031 path to:51889 distance to that node: 16.2 current total: 438047 path to:51890 distance to that node: 16.1 current total: 438063 path to:51891 distance to that node: 16.2 current total: 438079 path to:51892 distance to that node: 1.79769e+308 current total: 1.79769e+308 path to:51893 distance to that node: 16.3 current total: 1.79769e+308 path to:51894 distance to that node: 13.8 current total: 1.79769e+308 path to:51895 distance to that node: 13.9 current total: 1.79769e+308 I have checked my weights: if(edge_w<=0.0) edge_w = 0.1; if(edge_w >2.0) edge_w = 2.0; if( !(std::isnan(edge_w)) ) edge_w = 0.1; if( !(std::isfinite(edge_w)) ) edge_w = 0.1; boost::dijkstra_shortest_paths(m_ugraph, *vertex_iterator_begin, boost::distance_map(distanceMap)); typedef double Weight; typedef boost::property<boost::edge_weight_t, double> EdgeWeightProperty; typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, VertexProperties, EdgeWeightProperty> unGraph; Any ideas? Thanks a lot Tasos

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