- Boost-users - lists.boost.org

Push-Relabel undirected graph
by Charles Maske 19 Jul '14

19 Jul '14

Hi there, I'm working in a cut-tree implementation of gomoryhu algorithm and I have to compute max-flow on the input graph. I read about efficiency of the push-relabel algorithm and I want to do some tests but I can't get this because all reverse edges have to capacity equals 0. Someone knows one way to workaround this restriction? Other max-flow algorithms in BGL (edmonds-karp and boykov-kolmogorov) don't have this restriction, what do them more fast than push-relabel implementation. Thanks

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Generate random graphs
by Mandy Nour 19 Jul '14

19 Jul '14

Hello all, I need to generate random undirected simple graphs using The Erdos-Rényi methods and to extract its adjacency matrix into an std::vector. -- View this message in context: http://boost.2283326.n4.nabble.com/Generate-random-graphs-tp4665336.html Sent from the Boost - Users mailing list archive at Nabble.com.

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[variant] forward declarations
by Michael Powell 18 Jul '14

18 Jul '14

Hello, I've got some structs in a AST of sorts which the main player in the mix is a node. In at least one of the use cases, one of the variant types must be forward declared at the time the node can be declared. Possibly one or two other similar use cases. Error 2 error C2139: 'xml::xelement' : an undefined class is not allowed as an argument to compiler intrinsic type trait '__is_nothrow_constructible' i:\installs\development\boost.org\1.55.0\boost_1_55_0\stage\include\boost\type_traits\has_nothrow_constructor.hpp 24 1 xml However, I am bumping into C2139, above. Is there any way for variant to work with forward declared structs (or classes, etc)? Or am I just asking too much from C++? I am building against Visual Studio 2013, Boost 1.55. Thank you... Best regards, Michael Powell

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boost::lockfree::queue not working with -fgnu-tm
by Philipp Schoppe 17 Jul '14

17 Jul '14

Hello, I try to benchmark different queue implementations. I have a test program which includes the boost lockfree queue and some custom implementations where one is using gcc's STM. In order to compile it, I need to add the -fgnu-tm flag. I am using an up-to-date arch linux system with gcc 4.9.0 and boost 1.55.0 When adding this flag, I get a compilation error. This is a small example that illustrates the problem: errtest.cpp: #include <boost/lockfree/queue.hpp> int main () { boost::lockfree::queue<int> lfqueue; lfqueue.push(234); return 0; } Compiling it using g++ -std=c++11 -lboost_system -g -O3 -Wall -Werror -Wswitch-enum -fgnu-tm errtest.cpp -o test leads to an error.

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[Log] Extract severity value
by Olivier Tournaire 17 Jul '14

17 Jul '14

Hi all, I am trying to extract severity level from a log record, but i seems that I am doing it the wrong way. Here is the code I use: void LogDockWidget::receiveLog(boost::log::record_view const& rec, const std::string& log) { logging::value_ref< logging::trivial::severity_level > level = logging::extract< logging::trivial::severity_level >("Severity", rec); // ... } Here level.get() always returns "info". All my logs are done with the BOOST_LOG_TRIVIAL(...) macro. The formatter whereas displays correctly the severity level. Here is how it is defined: void LogDockWidget::init_logging() { boost::shared_ptr< logging::core > core = logging::core::get(); typedef sinks::synchronous_sink< QTextEditFormattedSinkBackend > sink_t; boost::shared_ptr< sink_t > sink(new sink_t); // ... logging::add_file_log( keywords::file_name = logFilename, keywords::auto_flush = true, keywords::format = ( BUILD_LOG_FORMATTER() ) ); sink->set_formatter( BUILD_LOG_FORMATTER() ); core->add_sink(sink); // Add attributes that we will use logging::add_common_attributes(); core->add_global_attribute( "ThreadID", attrs::current_thread_id()); } #define BUILD_LOG_FORMATTER() \ expr::stream \ << "[" << expr::format_date_time< boost::posix_time::ptime >("TimeStamp", "%Y-%m-%d %H:%M:%S") << "] " \ << expr::attr<unsigned int>("LineID") << " " \ << ": <" << logging::trivial::severity << "> " \ << " [" << expr::attr<attrs::current_thread_id::value_type>("ThreadID") << "] " \ << expr::if_(expr::has_attr(scope_attribute)) \ [ \ expr::stream << "[" << scope_attribute << "] " \ ] \ << expr::message Could you please let me know what I am doing wrong? Regards, Olivier

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Re: [Boost-users] Intrusive: Checking for undefined behaviour
by Brian Wood 16 Jul '14

16 Jul '14

Ion Gazta?aga writes: >El 15/07/2014 5:33, Brian Wood escribi?: >> I was reading here about some of the sanitizers >> >> http://cplusplusmusings.wordpress.com/ >> >> and decided to try it out the undefined behavior >> sanitizer on some code. One thing that came >> out was related to the Intrusive library. > > Can you try with the release candidate (http://boost.cowic.de/rc/) for > Boost 1.56? I solved some undefined behaviour issues recently but I > don't know if this is one of them. I tested it with 1.56 now and the sanitizer is no longer reporting a problem with Intrusive. It looks like whatever you did has helped. I appreciate your being on top of this. -- Brian Ebenezer Enterprises - "Let a man so consider us, as servants of Messiah and stewards of the mysteries of G-d." First Corinthians 4 http://webEbenezer.net

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1.56.0 beta release candidate 2 available for testing
by Marshall Clow 16 Jul '14

16 Jul '14

The second release candidate files for 1.56.0 beta are available at http://boost.cowic.de/rc/ As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. This helps ensure the candidates build OK before we push them out to SourceForge. The files (and associated md5s) are: MD5 (boost-1_56_0_b1_rc2.7z) = cd6267325a8dadbb82b384c4776ee450 MD5 (boost-1_56_0_b1_rc2.tar.bz2) = b74cd72043b6b2fa16c6690633acb422 MD5 (boost-1_56_0_b1_rc2.tar.gz) = b51810be6737e73a4deee70e84895ca7 MD5 (boost-1_56_0_b1_rc2.zip) = f4ceb73492ae7d9b1843d841498850e5 Since this is the first post-git release, we are expecting some teething pains with this release. Please test extensively. Besides bug fixes the TypeIndex library has been included, and I think that the problems that mjklaim(a)gmail.com was seeing have been fixed. I would like to post this to SourceForge Thursday night/Friday morning, if possible. Thank you. --The release managers

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[log] translating 3rd party logging messages
by Olaf Peter 16 Jul '14

16 Jul '14

Hello, shown my translator for Qt using boost.log: void qt_message_translator(QtMsgType type, const QMessageLogContext &context, const QString &msg) { QString const context_message = QString("Qt [") + context.function + " (" + context.file + ":" + QString::number(context.line) + ")] "; QByteArray const ctx_msg = context_message.toUtf8(); QByteArray const qt_msg = msg.toUtf8(); boost::log::sources::severity_logger<severity_level> slg; switch (type) { case QtDebugMsg: BOOST_LOG_SEV(slg, debug) << ctx_msg.constData() << qt_msg.constData(); break; case QtWarningMsg: BOOST_LOG_SEV(slg, warning) << ctx_msg.constData() << qt_msg.constData(); break; case QtCriticalMsg: BOOST_LOG_SEV(slg, error) << ctx_msg.constData() << qt_msg.constData(); break; case QtFatalMsg: BOOST_LOG_SEV(slg, fatal) << ctx_msg.constData() << qt_msg.constData(); break; default: BOOST_LOG_SEV(slg, fatal) << ctx_msg.constData() << qt_msg.constData(); break; } } ... qInstallMessageHandler(qt_message_translator); The problem is more of cosmetic nature; the logging format output is different from what is used normally - it looks alien. Since the context data is available I assume I can write an own logging source writing/fill the log records filled with the context information. Additionally I want to add a "Scope" or "Library" flag "Qt" (Scope may be not the best choise since it's used in another context). But I didn't find an example in the boost.log module to find the entry; is writing an own source the right way? How to use it in the qt_message_translator? Thanks, Olaf

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adjacency_list.hpp won't compile
by Alexander While 16 Jul '14

16 Jul '14

Hello, I just recently found Boost, and I am attempting to use it in a project I am working on. However, in my attempts to make simple graphs with the graph/adjacency_list.hpp subdirectory, I get a compiler error within the code for adjacency_list.hpp. I don't know if I can copy the error message correctly, but the errors seem centered around lines 1503-1505, those saying typedef typename lookup_one_property<vertex_property_type, vertex_bundle_t>::type vertex_bundled; typedef typename lookup_one_property<edge_property_type, edge_bundle_t>::type edge_bundled; typedef typename lookup_one_property<graph_property_type, graph_bundle_t>::type graph_bundled; then lines 2027 and 275 are mentioned. The code I myself wrote compiles fine on its own. I'm using the IDE Dev-C++.

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Intrusive: Checking for undefined behaviour
by Brian Wood 15 Jul '14

15 Jul '14

I was reading here about some of the sanitizers http://cplusplusmusings.wordpress.com/ and decided to try it out the undefined behavior sanitizer on some code. One thing that came out was related to the Intrusive library. /home/brian/boost_1_55_0/boost/intrusive/detail/tree_node.hpp:164:44: runtime error: member access within null pointer of type 'const boost::intrusive::bhtraits<myString, boost::intrusive::rbtree_node_traits<void *, false>, 2, boost::intrusive::default_tag, 3>' I have a couple of lines that may be related to: struct myString : set_base_hook<::boost::intrusive::link_mode<::boost::intrusive::auto_unlink> > and ::boost::intrusive::set<myString, constant_time_size<false> > files; Can someone tell me how serious this is? Thank you. -- Brian Ebenezer Enterprises - In G-d we trust. http://webEbenezer.net

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