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[BGL] Segmentation fault in clear_vertex
by Daniel Trebbien 02 Sep '10

02 Sep '10

I am attempting to modify my implementation of the Stoer–Wagner min-cut algorithm to modify the input graph. In the code sample below, t and s are vertex_descriptors that were calculated by a call to boost::detail::stoer_wagner_phase: boost::tie(s, t, w) = boost::detail::stoer_wagner_phase(g, assignments, weights, pq); assert(s != t); // ... std::multimap<vertex_descriptor, edge_descriptor> sOutEdges; BGL_FORALL_OUTEDGES_T(s, e, g, UndirectedGraph) { const vertex_descriptor u = target(e, g); if (t != u) { sOutEdges.insert(std::make_pair(u, e)); } } BGL_FORALL_OUTEDGES_T(t, e, g, UndirectedGraph) { const vertex_descriptor u = target(e, g); const weight_type eWeight = get(weights, e); typename std::multimap<vertex_descriptor, edge_descriptor>::iterator sOutEdgesIt, sOutEdgesEnd; boost::tie(sOutEdgesIt, sOutEdgesEnd) = sOutEdges.equal_range(u); if (sOutEdgesIt != sOutEdgesEnd) { for(; sOutEdgesIt != sOutEdgesEnd; ++sOutEdgesIt) { put(weights, sOutEdgesIt->second, get(weights, sOutEdgesIt->second) + eWeight); } } else if (t != u) { // need to update e to set the source to s edge_descriptor ePrime; boost::tie(ePrime, boost::tuples::ignore) = add_edge(s, u, g); put(weights, ePrime, eWeight); } } clear_vertex(t, g); The segmentation fault occurs in the call to clear_vertex, but does not occur if I comment out the line that adds an edge to the graph g. The type of g, by the way, is: boost::adjacency_list<boost::listS, boost::vecS, boost::undirectedS, boost::no_property, boost::property<boost::edge_weight_t, int> > Why does adding an edge between vertices s and target(e, g), both of which are not equal to t, cause a segmentation fault? For reference, gdb says that the fault occurs on line 999 of boost/graph/detail/adjacency_list.hpp: // O(E/V * E/V) template <class Config> inline void clear_vertex(typename Config::vertex_descriptor u, undirected_graph_helper<Config>& g_) { typedef typename Config::global_edgelist_selector EdgeListS; BOOST_STATIC_ASSERT((!is_same<EdgeListS, vecS>::value)); typedef typename Config::graph_type graph_type; typedef typename Config::edge_parallel_category Cat; graph_type& g = static_cast<graph_type&>(g_); typename Config::OutEdgeList& el = g.out_edge_list(u); typename Config::OutEdgeList::iterator ei = el.begin(), ei_end = el.end(); for (; ei != ei_end; ++ei) { detail::erase_from_incidence_list (g.out_edge_list((*ei).get_target()), u, Cat()); g.m_edges.erase((*ei).get_iter()); *// line 999* } g.out_edge_list(u).clear(); } Program received signal SIGSEGV, Segmentation fault. std::_List_node_base::unhook (this=0x3d7a38) at ../../../../gcc-4.4.0/libstdc++-v3/src/list.cc:134 134 ../../../../gcc-4.4.0/libstdc++-v3/src/list.cc: No such file or director y. in ../../../../gcc-4.4.0/libstdc++-v3/src/list.cc (gdb) bt #0 std::_List_node_base::unhook (this=0x3d7a38) at ../../../../gcc-4.4.0/libstdc++-v3/src/list.cc:134 #1 0x0045fa26 in std::list<boost::list_edge<unsigned int, boost::property<boost ::edge_weight_t, int, boost::no_property> >, std::allocator<boost::list_edge<uns igned int, boost::property<boost::edge_weight_t, int, boost::no_property> > > >: :_M_erase (this=0x22fa9c, __position=...) at c:/mingw/bin/../lib/gcc/mingw32/4.4.0/include/c++/bits/stl_list.h:1424 #2 0x0045fa0c in std::list<boost::list_edge<unsigned int, boost::property<boost ::edge_weight_t, int, boost::no_property> >, std::allocator<boost::list_edge<uns igned int, boost::property<boost::edge_weight_t, int, boost::no_property> > > >: :erase (this=0x22fa9c, __position=...) at c:/mingw/bin/../lib/gcc/mingw32/4.4.0/include/c++/bits/list.tcc:111 #3 0x00413ec9 in boost::clear_vertex<boost::detail::adj_list_gen<boost::adjacen cy_list<boost::listS, boost::vecS, boost::undirectedS, boost::no_property, boost ::property<boost::edge_weight_t, int, boost::no_property>, boost::no_property, b oost::listS>, boost::vecS, boost::listS, boost::undirectedS, boost::no_property, boost::property<boost::edge_weight_t, int, boost::no_property>, boost::no_prope rty, boost::listS>::config> (u=5, g_=...) at c:/mingw/bin/../lib/gcc/mingw32/4.4.0/../../../../include/boost/graph/det ail/adjacency_list.hpp:999 #4 0x0041b0cc in boost::detail::stoer_wagner_min_cut<boost::adjacency_list<boos t::listS, boost::vecS, boost::undirectedS, boost::no_property, boost::property<b oost::edge_weight_t, int, boost::no_property>, boost::no_property, boost::listS> , boost::adj_list_edge_property_map<boost::undirected_tag, int, int&, unsigned i nt, boost::property<boost::edge_weight_t, int, boost::no_property>, boost::edge_ weight_t>, boost::associative_property_map<std::map<int, bool, std::less<int>, s td::allocator<std::pair<int const, bool> > > >, boost::shared_array_property_map <unsigned int, boost::vec_adj_list_vertex_id_map<boost::no_property, unsigned in t> >, boost::d_ary_heap_indirect<unsigned int, 4u, boost::shared_array_property_ map<unsigned int, boost::vec_adj_list_vertex_id_map<boost::no_property, unsigned int> >, boost::shared_array_property_map<int, boost::vec_adj_list_vertex_id_map <boost::no_property, unsigned int> >, std::greater<int>, std::vector<unsigned in t, std::allocator<unsigned int> > > > (g=..., weights=..., parities=..., assignments=..., pq=...) ...

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does pool::release_memory() really require an ordered pool?
by Mark Rajcok 02 Sep '10

02 Sep '10

On page http://www.boost.org/doc/libs/1_44_0/libs/pool/doc/interfaces/pool.html there is this precondition for release_memory(): "t must be ordered". Does that mean that ordered_malloc() must always be used, if I want to use release_memory()? Looking at the implementation for release_memory(), it appears to be iterating through chunks in each block, which I wouldn't expect if ordered_malloc() were always used. What I'm really after: I want to use object_pool, but periodically I'd like to reclaim/release any memory blocks that are no longer in use. In my application, I may have traffic spikes, where I allocate a lot of memory, but then later (after spiking) I'd like to release it. (The object pools will persist for the life of the application, and there will probably always be some "active objects" -- i.e., allocated from the pool and not free()d yet.) (I'm hoping the documentation may be out of date, and release_memory() can be used on pools that don't use ordered_malloc() and on object_pools.) -- Mark

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Struggling to implement bzip2 on windows
by Jared James Thompson 02 Sep '10

02 Sep '10

Hi All, I'm a VS2008 user, trying to use the ESBTL library for a project, which implements Boost to do many operations. ESBTL #includes <boost/iostreams/filter/bzip2.hpp>, which has been disabled for the Boostpro installation of windows. Quite simply, I'm struggling to get bzip2 installed and set up so that boost runs with bzip2 enabled. Has anybody done this before? Can anyone offer me more information than "compile from source?" best, Jared -- Jared James Thompson Department of Medicinal Chemistry and Molecular Pharmacology Laboratory for Computational Drug Design and Biology RHPH 504C Heine Pharmacy Building 575 Stadium Mall Drive West Lafayette, IN 47907-2091

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lamba: QStringList <<
by Hicham Mouline 02 Sep '10

02 Sep '10

Hello, the following for_each call with _1 fails to compile #include <QStringList.h> #include <boost/lambda/lambda.hpp> using namespace boost::lambda; QStringList items_list; std::for_each(begin_items(),end_items(), items_list << _1 ); QStringList has these << operators defined: QStringList& operator<< ( const QString& str ); QStringList& operator<< ( const QStringList& other ); the type of item iterator returned by begin_items() is: const char* const* QString has a ctor: QString (const char * str) The compilation error is: error C2678: binary '<<' : no operator found which takes a left-hand operand of type 'const QStringList' (or there is no acceptable conversion) I don't see why it tries to find a << that takes a ***const*** QStringList left-hand operand? Regards,

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Boost.Random and Dieharder et al.
by Patricia Hawley 02 Sep '10

02 Sep '10

Hi, I am working with a team developing some utilities for a simulation, and one of our requirements is to test the quality of the random generators. We based the utility on Boost.Random, but now have to show that that was a good decision. Has anyone verified the generators (e.g. Mersenne Twister or Linear Congruential ) in Boost.Random pass the Dieharder, Ent, and/or TestU01 suites? Any comments or suggestions on this are appreciated, Pat

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Re: [Boost-users] Boost-users Digest, Vol 2466, Issue 3
by Clarke, Carus V 01 Sep '10

01 Sep '10

Steven Watanabe wrote: > AMDG > > Clarke, Carus V wrote: > >> It looks like stat is setting errno to ENOENT. > >> Do you get the same behavior if the file exists before > starting the > >> program? > > > > Yes, the behavior is the same whether the program writes > the file or if the file had been previously written. > > > > Okay. Try using stat directly, instead of using Boost.Filesystem. > If that works, then can you use a debugger to find exactly > what arguments Boost.Filesystem is passing to stat? > > In Christ, > Steven Watanabe > Actually, the Boost.Filesystem library for Boost 1.44 uses the Windows API GetFileAttributes functions for reading file status on Cygwin, and it was in calls to these functions that things were failing. Since my last post, the Cygwin developers have updated the base Cygwin system (to 1.7.7-1). Updating my Cygwin installation to the new version has fixed the problem. Apparently, the 1.7.6-1 version had some bugs that were inadvertently introduced in an attempt to improve Cygwin functionality. I do have a question that might be better asked in a new thread, but here it is. Why does the Boost.Filesystem library force the use of Windows-style paths for Cygwin? The Cygwin system prefers Posix or mixed paths with forward slashes as separators. The use of Win32 paths on Cygwin is now deprecated, and Cygwin actually issues a warning the first time it encounters a Windows-style path. See http://cygwin.com/cygwin-ug-net/using.html#using-pathnames for more information. The Cygwin GCC 4.3.4 compiler no longer supports the -mno-cygwin option that was supported under Cygwin 1.5 and earlier. This means that any application created with this compiler depends on the Cygwin dll. Also, Boost does not appear to have a Cygwin platform for regression testing. Would it help if I or someone else could set one up? Thanks for your help. Carus V. (Bud) Clarke carus.v.clarke(a)boeing.com

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Problem using serialization::xml_archive with polymrphic classes
by przemyslaw.sliwa＠uk.bnpparibas.com 01 Sep '10

01 Sep '10

HelloHello, I have written code below and it works fine when using text archives. However, when I try to run it with the xml archives it is throwing a strange error saying "Invalid XML tag name". I have no idea what that means and could not find it in the documentation of the serialization library. Could someone tell me what I am doing wrong in this code? Thanks a lot for help! #include <boost/smart_ptr/shared_ptr.hpp> #include <boost/archive/xml_oarchive.hpp> #include <boost/archive/xml_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/serialization/vector.hpp> #include <boost/serialization/string.hpp> #include <boost/serialization/shared_ptr.hpp> #include <boost/date_time/local_time/local_time.hpp> #include <boost/serialization/export.hpp> #include <iostream> using namespace boost; using namespace std; class Actor { public: Actor( void ) {} Actor( char gender ) : gender( gender ) {} virtual ~Actor() {} char Gender( void ) const { return gender; } private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & BOOST_SERIALIZATION_NVP(gender); } char gender; }; class Crit: public Actor { public: Crit( void ) {} Crit( int age ) : age( age ) { } int Age( void ) const { return age; } private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & BOOST_SERIALIZATION_NVP(boost::serialization::base_object< Actor >( *this )); ar & BOOST_SERIALIZATION_NVP(age); } int age; }; class Food: public Actor { public: Food( void ) {} Food( int energy ) : energy( energy ) { } int Energy( void ) const { return energy; } private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & BOOST_SERIALIZATION_NVP(boost::serialization::base_object< Actor >( *this )); ar & BOOST_SERIALIZATION_NVP(energy); } int energy; }; BOOST_CLASS_EXPORT_GUID( Actor, "Actor") BOOST_CLASS_EXPORT_GUID( Crit, "Crit") BOOST_CLASS_EXPORT_GUID( Food, "Food") template< typename T > void save( T& data, string filename ) { ofstream ofs( filename.c_str() ); boost::archive::xml_oarchive oa( ofs ); oa & BOOST_SERIALIZATION_NVP(data); } template< typename T > void load( T& data, string filename ) { ifstream ofs( filename.c_str() ); boost::archive::xml_iarchive ia( ofs ); ia & BOOST_SERIALIZATION_NVP(data); } void TestAlpha( void ) { shared_ptr< Crit > critAlpha( new Crit( 18 ) ); shared_ptr< Crit > critBravo( new Crit( 19 ) ); shared_ptr< Food > foodAlpha( new Food( 20 ) ); shared_ptr< Food > foodBravo( new Food( 21 ) ); vector< shared_ptr< Actor > > conAlpha; vector< shared_ptr< Actor > > conBravo; conAlpha.push_back( critAlpha ); conAlpha.push_back( foodAlpha ); // save string filename = "sav.sav"; save( conAlpha, filename ); // test assert( critBravo->Age() == 19 ); assert( foodBravo->Energy() == 21 ); // load load( conBravo, filename ); // test critBravo = dynamic_pointer_cast< Crit >( conBravo[ 0 ] ); assert( critBravo->Age() == 18 ); foodBravo = dynamic_pointer_cast< Food >( conBravo[ 1 ] ); assert( foodBravo->Energy() == 20 ); } int main() { try { TestAlpha(); } catch(boost::archive::archive_exception& e) { return -1; } return 0; } ___________________________________________________________ This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and delete this e-mail. Any unauthorised copying, disclosure or distribution of the material in this e-mail is prohibited. Please refer to http://www.bnpparibas.co.uk/en/information/legal_information.asp?Code=ECAS-… for additional disclosures.

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mpl::set and mpl::fold
by Paul Graphov 01 Sep '10

01 Sep '10

Hello Boost Users, I've encountered a problem while using mpl::fold with mpl::set I've defined a template to check if one sequence contains all elements of the other: namespace mpl = boost::mpl; template<class A, class B> struct subset : mpl::fold< A, mpl::true_, mpl::and_<mpl::_1, mpl::contains<B, mpl::_2> > > {}; It works fine with lists and vectors but when first template parameter (A) is set or set_c it fails to compile. Did I miss something? Why is it impossible to iterate through a set via fold? p.s. tested on gcc and clang under linux. p.p.s. compilation error is quite huge, the main message is /usr/local/include/boost/mpl/eval_if.hpp:38: error: no type named ‘type’ in ‘struct boost::mpl::next<boost::mpl::s_iter<boost::mpl::set_c<int, 1l, 9223372036854775807l, 9223372036854775807l, 9223372036854775807l, 9223372036854775807l, 9223372036854775807l, 9223372036854775807l, 9223372036854775807l, 9223372036854775807l, 9223372036854775807l, 9223372036854775807l, 9223372036854775807l, 9223372036854775807l, 9223372036854775807l, 9223372036854775807l, 9223372036854775807l, 9223372036854775807l, 9223372036854775807l, 9223372036854775807l, 9223372036854775807l>, boost::mpl::set0_c<int> > >’

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[gil] bit_aligned_pixel_iterator
by Christian Henning 01 Sep '10

01 Sep '10

Hi there, I have a problem with extracting the correct values out of a 3bit gray image. The test code below displays my problem. Here, there is a vector of unsigned chars which create a particular bit pattern though all pixels in the image should have the same values. The bit pattern is: 1011 0110 0110 1101 1101 1011 0000 0000. On my machine ( x86 ) this should be read out in values of 110b ( which is 6 ) for all pixels. Instead my code reads out: 6, 6, 2, 6, 6, 0, 6, 6, 0. Here is the code: #include <cassert> #include <vector> #include <boost/gil/gil_all.hpp> using namespace std; using namespace boost; using namespace gil; int main() { typedef bit_aligned_image1_type< 3, gray_layout_t >::type gray3_image_t; typedef gray3_image_t image_t; typedef image_t::view_t view_t; typedef view_t::reference ref_t; typedef view_t::value_type pixel_t; typedef bit_aligned_pixel_iterator< ref_t > iterator_t; vector< unsigned char > buf( 4 ); buf[0] = 182; buf[1] = 109; buf[2] = 219; buf[3] = 0; iterator_t it( &buf[0], 0 ); ref_t p1 = *it; it++; ref_t p2 = *it; it++; ref_t p3 = *it; it++; ref_t p4 = *it; it++; ref_t p5 = *it; it++; ref_t p6 = *it; it++; ref_t p7 = *it; it++; ref_t p8 = *it; it++; ref_t p9 = *it; it++; unsigned char v1 = get_color( p1, gray_color_t() ); unsigned char v2 = get_color( p2, gray_color_t() ); unsigned char v3 = get_color( p3, gray_color_t() ); unsigned char v4 = get_color( p4, gray_color_t() ); unsigned char v5 = get_color( p5, gray_color_t() ); unsigned char v6 = get_color( p6, gray_color_t() ); unsigned char v7 = get_color( p7, gray_color_t() ); unsigned char v8 = get_color( p8, gray_color_t() ); unsigned char v9 = get_color( p9, gray_color_t() ); return 0; } The first two values are correct since they covered by the first byte. The third value doesn't seem to take in account the first bit of the second byte. I think this is incorrect. The stepping of the bits of by the iterator seems correct. Each value that is covered by one byte completely is correct but when a value is stretched over two bytes there seems to be a problem. Regards, Christian

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[type_traits]: is_boost_optional?
by Roland Bock 01 Sep '10

01 Sep '10

Hi, is there something in Boost.TypeTraits (or somewhere else) that allows me to check if a type is a boost::optional? I'd like to do something like this: template<typename T> typename enable_if<is_boost_optional<T> >, T::value_type>::type foo(const T&); Thanks and regards, Roland

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