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[boost C++] algorithm for shortest path
by Boost lzw 13 Oct '09

13 Oct '09

Hi there, For the following unidirectional (one-direct only) pairs: A-B; G-H; B-D; D-G; H-K; K-D; The shortest path between A and D is: A-B-D, but none between A and H. Which Boost library should I use to develop such an algorithm or any hint on design it ? Thanks in advance. Robert

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Formal Review of Boost.Polygon extended one more week: until September 9, 2009
by Fernando Cacciola 13 Oct '09

13 Oct '09

Dear boost users, The review of Boost.Polygon was initially scheduled to end today. However, the discussions are in their best moment only now so the review period was extended by one week, until September 9, 2009 (that is next Wednesday). Best Fernando Cacciola Review Manager

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[python] Alternative to explicitly defining function pointers?
by Boris Schaeling 13 Oct '09

13 Oct '09

Is it possible to simplify this code without defining a function pointer? ----- struct X { void y(std::string) { } std::string y() { return ""; } }; std::string (X::*get_y)() = &X::y; class_<X>("X").add_property("y", get_y); ----- I tried to set the signature but if the documentation is right signatures only make sense for function objects - so this code doesn't work: class_<X>("X").add_property("y", make_function(&X::y, default_call_policies(), mpl::vector<std::string>())); Anything else Boost.Python offers to make adding properties even easier? If there is nothing I know at least that I didn't miss a shortcut and have to define function pointers myself. Boris

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[PREPROCESSOR] Working around the 256 element limit for sequences
by Rush Manbert 13 Oct '09

13 Oct '09

We define exception error codes and other useful information like this: #define EXCEPTION_TABLE \ ( (enumName0, "description string", "another sting", "yet another string") ) \ ( (enumName1, "description string", "another sting", "yet another string") ) \ . . . // End EXCEPTION_TABLE def Then we write a macro that creates an enum like this: #define ENUM_ERROR_CODES(EXCEPTION_TABLE_MACRO_NAME, firstErrorCodeValue)\ public: typedef enum \ { \ \ BOOST_PP_SEQ_FOR_EACH_I(MAKE_EXCEPTION_CODE_ENUM, ~, EXCEPTION_TABLE_MACRO_NAME) \ } ErrorCodesT; \ // End macro definition and we invoke ENUM_ERROR_CODES as: ENUM_EROR_CODEAS(EXCEPTION_TABLE, 1) This has worked just beautifully until recently. Now we're trying to use this code to define an enum (and other things) based on an EXCEPTION_TABLE that carries error code for a hardware device. There are about 500 of them. I ran into the 256 element limitation for sequences. I have tried rewriting the enum macro like this: #define ENUM_ERROR_CODES(EXCEPTION_TABLE_MACRO_NAME, firstErrorCodeValue)\ public: typedef enum \ { \ \ BOOST_PP_SEQ_FOR_EACH_I(MAKE_EXCEPTION_CODE_ENUM, ~, BOOST_PP_SEQ_SUBSEQ(EXCEPTION_TABLE_MACRO_NAME, 0, 250))\ BOOST_PP_SEQ_FOR_EACH_I(MAKE_EXCEPTION_CODE_ENUM, ~, BOOST_PP_SEQ_SUBSEQ(EXCEPTION_TABLE_MACRO_NAME, 250, 250))\ BOOST_PP_SEQ_FOR_EACH_I(MAKE_EXCEPTION_CODE_ENUM, ~, BOOST_PP_SEQ_SUBSEQ(EXCEPTION_TABLE_MACRO_NAME, 500, 250))\ BOOST_PP_SEQ_FOR_EACH_I(MAKE_EXCEPTION_CODE_ENUM, ~, BOOST_PP_SEQ_SUBSEQ(EXCEPTION_TABLE_MACRO_NAME, 750, 250))\ } ErrorCodesT; \ // End macro definition thinking that I could just peel off groups of 250, but that doesn't work. I can peel off the first N, where N is <= the size of the sequence, but I certainly can't do what I wrote. Each of our exception classes is defined this way, and the number of elements in each EXCEPTION_TABLE is different for each. Is there some standard method for working around this problem? Thanks, Rush

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exception error_info list?
by denis 12 Oct '09

12 Oct '09

Hi, what do you think about exposing the error_info-map of boost::exception? I would like to get all attached error infos from one exception. Then, everyone could implement his own version of diagnostic_information() without relying on boost internals. Beside that, I had another idea: When translating an exception it would be possible to copy all error_infos from the originating exception to the new one. How do you handle this loss of information at the time? thanks.

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Numpy ndarray as argument or return value using boost python
by Pim Schellart 12 Oct '09

12 Oct '09

Hi Everyone, I tried to find a good example for this but after spending two days on google and one day getting pyublas to compile I decided to call for help. I want to give a numpy ndarray as an argument to a c++ method, calculate something and return the output as an ndarray to Python. I would prefer not to use another library (such as PyUblas) for this so I do not have to add another dependency to my program. Since the latest information on boost python is quite outdated (uses numeric) I would like to know the following. 1. Is boost python still maintained or should I switch to another tool. 2. Is numpy supported, and if so, 3. can someone give me a basic example of how to use it. Kind regards, Pim Schellart

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[BGL] read_graphviz and Bundle Properties
by Giuseppe Di Guglielmo 12 Oct '09

12 Oct '09

Dear all, here http://www.boost.org/doc/libs/1_40_0/libs/graph/doc/read_graphviz.html is reported how to use the read_graphviz function with old style "property list". How can I use the read_graphviz() function with bundle properties? This is my graph-type definition --- struct VertexId_t { std::size_t id; }; struct EdgeId_t { std::size_t id; }; typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, VertexId_t, EdgeId_t> Graph_t; --- And this is the DOT file: --- G { 0 [id="v0"]; 1 [id="v1"]; 0->0 [id="e0"]; 0->0 [id="e1"]; 0->1 [id="e2"]; } --- Cheers, G.

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[Proto] proto::function and constness
by Kim Kuen Tang 12 Oct '09

12 Oct '09

Hi all, let _o_ be any proto terminal and v a vector. I would like to extract the vector v from the expression _o_(v) to do some modification on this vector. For this purpose i defined a grammar Rhs to extract the most right hand side of the tree. But unfortunately the compiler is asking me for constness for this code: boost::result_of<Rhs(Expr)>::type & result = Rhs()(expr); Whereas the expression _o_ + v compiles fine without asking me for constness. Am I missing something? Best regards, Kim Here is the code to demonstrate the problem. # include <vector> # include <iostream> # include <algorithm> # include <boost/proto/proto.hpp> namespace proto = boost::proto; namespace mpl = boost::mpl; using proto::_; template<typename Expr> struct MixedExpr; struct MixedDomain : proto::domain<proto::generator<MixedExpr> > {}; template<typename Expr> struct MixedExpr : proto::extends<Expr, MixedExpr<Expr>, MixedDomain> { explicit MixedExpr(Expr const &expr) : proto::extends<Expr, MixedExpr<Expr>, MixedDomain>(expr) {} }; struct oo { friend std::ostream &operator<<(std::ostream &s, oo const&) { return s << "oo"; } }; proto::terminal<oo>::type const _o_ = {{}}; template<typename T> struct IsMixed : mpl::false_ {}; template<typename T, typename A> struct IsMixed<std::vector<T, A> > : mpl::true_ {}; namespace MixedOps { BOOST_PROTO_DEFINE_OPERATORS(IsMixed,MixedDomain) }; namespace boost { namespace proto { template<typename T, typename A> std::ostream &operator<<(std::ostream &s, std::vector<T, A> const& ) { return s << "std::vector"; } }} struct Rhs : proto::or_< proto::when<proto::terminal<_>, proto::_value > ,proto::when<_, Rhs(proto::_child1)> > {}; template<typename Expr> void o_o(Expr& expr) { proto::display_expr(expr); boost::result_of<Rhs(Expr)>::type & result = Rhs()(expr); std::fill(result.begin(), result.end(),2); }; int main() { using namespace MixedOps; std::vector<int> u(10),v(10); //o_o( _o_(v) ); //uncomment this won't compile o_o( u+v ); std::copy(v.begin(),v.end(),std::ostream_iterator<int>(std::cout,",") ); std::cout<<std::endl; return 1; }

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graphlib changes in 1.40
by Ralph Gauges 12 Oct '09

12 Oct '09

Hi, I use the graph library in some of my programs and I recently moved to boost 1.40 because older version did not work on snow leopard. I noticed that although the changelog does not mention any changes in the graph library, some of the layout algorithms have changes (e.g. random layout and fruchterman reingold) in the way they are called. They seem to use some new topology concept, unfortunately the documentation for those algorithms have not been updated. I was wondering if there is any updated documentation especially on the fruchterman reingold algorithm. I tried to guess what the new parameters mean, but so far I have not been able to get the same results as with the graph library from 1.39. No matter how I set the values so far, all my nodes end up essentially in the same place, although they are all disconnected and I would expect them to be spread out. Thanks a lot Ralph

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boost-users@lists.boost.org
by hamidouche 12 Oct '09

12 Oct '09

hello I wanna build boost1_40 on a linux 64 machine (this is the my machine configuration) 2.6.28-11-generic #42-Ubuntu SMP Fri Apr 17 01:58:03 UTC 2009 x86_64 GNU/Linux compiler Intel 11.0 when I run ./bjam --toolset=intel I have this error message "icpc" -c -xc++ -O3 -w1 -inline-level=2 -pthread -fPIC -DBOOST_ALL_NO_LIB=1 -DBOOST_SERIALIZATION_DYN_LINK=1 -DNDEBUG -I"." -c -o "bin.v2/libs/serialization/build/intel-linux/release/threading-multi/basic_text_iprimitive.o" "libs/serialization/src/basic_text_iprimitive.cpp" ...failed intel-linux.compile.c++ bin.v2/libs/serialization/build/intel-linux/release/threading-multi/basic_text_iprimitive.o... intel-linux.compile.c++ bin.v2/libs/serialization/build/intel-linux/release/threading-multi/basic_text_oprimitive.o (0): internal error: backend signals compilation aborted for libs/serialization/src/basic_text_oprimitive.cpp (code 4) "icpc" -c -xc++ -O3 -w1 -inline-level=2 -pthread -fPIC -DBOOST_ALL_NO_LIB=1 -DBOOST_SERIALIZATION_DYN_LINK=1 -DNDEBUG -I"." -c -o "bin.v2/libs/serialization/build/intel-linux/release/threading-multi/basic_text_oprimitive.o" "libs/serialization/src/basic_text_oprimitive.cpp" ...failed intel-linux.compile.c++ bin.v2/libs/serialization/build/intel-linux/release/threading-multi/basic_text_oprimitive.o... intel-linux.compile.c++ bin.v2/libs/serialization/build/intel-linux/release/threading-multi/binary_iarchive.o (0): internal error: backend signals Please what wrong with this installing ? what should I change ?? Thanks

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Using fftw_complex with Boost.MultiArray?
by Rhys Ulerich 12 Oct '09

12 Oct '09

Has anyone successfully used FFTW's fftw_complex typedef[1] with Boost.MultiArray? Under the covers it is an array of length two, which seems to interact poorly with MultiArray's type assumptions. The attached test.cc fails to compile on g++ 4.3 and icpc 10.1. - Rhys [1] http://www.fftw.org/doc/Complex-numbers.html

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[xpressive] Shouldn't external placeholder variables allow consts?
by Ami Ganguli 12 Oct '09

12 Oct '09

I came across an interesting problem: what.let(_placeholder = this); fails to compile, because 'this' is a const pointer. A simple workaround: MyClass *_this = this; what.let(_placeholder = _this); But surely this shouldn't be necessary? Couldn't the right hand side of the let be declared const? Regards, Ami.

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[MPL] bitnot function??
by Sebastian Weber 12 Oct '09

12 Oct '09

Hi! I was wondering how come there is no bitwise not (~) operation in the mpl? Is there an equivalent statement? Thanks, Sebastian

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[asio] crash on io_service object destruction.
by Alexander Gutenev 12 Oct '09

12 Oct '09

Hi This is probably bug in my app, but I need an idea how to track it down. Seen on MSVC8, XP Occurs after io_service, which is processing many timers, sockets and posts in one thread is stopped from another thread. It is stopped fine, however it crashes on service object destruction at this line: // Delete the timer. void destroy() { destroy_func_(this); //// } destroy_func_ is often 0xfeeefeee, but sometimes it is 0x0 or any other value. Call stack is: boost::asio::detail::timer_queue<boost::asio::time_traits<boost::posix_time::ptime> >::timer_base::destroy() Line 211 + 0xe bytes C++ boost::asio::detail::timer_queue<boost::asio::time_traits<boost::posix_time::ptime> >::destroy_timer_list(boost::asio::detail::timer_queue<boost::asio::time_traits<boost::posix_time::ptime> >::timer_base * & t=0x01acd090) Line 415 C++ boost::asio::detail::timer_queue<boost::asio::time_traits<boost::posix_time::ptime> >::destroy_timers() Line 189 C++ boost::asio::detail::win_iocp_io_service::shutdown_service() Line 148 + 0x2c bytes C++ boost::asio::detail::service_registry::~service_registry() Line 75 + 0xf bytes C++ boost::asio::detail::service_registry::`scalar deleting destructor'() + 0x2b bytes C++ boost::asio::io_service::~io_service() Line 52 + 0x2e bytes C++ Any ideas ?

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How to delete the shared memory
by manish4gupta 12 Oct '09

12 Oct '09

Hi, I am working on shared memory and trying to delete the shared memory using ipcrm -m shmid command but it is not able to delete the shared memory. Even if I reboot my system, it does seem to be deleting the shared memory. I can not use sharedmemory:: remove function since i am not aware of shared memory region name now. Please help me. Thanks in advance. -- View this message in context: http://www.nabble.com/How-to-delete-the-shared-memory-tp25849509p25849509.h… Sent from the Boost - Users mailing list archive at Nabble.com.

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[units] newbie : plane_angle
by Damien R 11 Oct '09

11 Oct '09

Hi, I just discover boost::units and I want to know how it works in this case : quantity<si::plane_angle> angle(45 * degree); When the constructor is called, is the argument converted in radian or not ? Moreover, it is possible to have : quantity<??::plane_angle> angle(45 * degree); angle += pi / 4 * radian; cout << angle << endl; cout << quantity<degree::plane_angle>(angle) << endl; cout << quantity<radian::plane_angle>(angle) << endl; cout << angle.value<degree>() << endl; cout << angle.value<radian>() << endl; output : 45 deg + pi / 4 rad 90 deg pi / 2 rad 90 1.57079632679 Thanks. -- Damien R

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[shared_ptr] Using a custom delete function that is a class member function
by Ryan McConnehey 11 Oct '09

11 Oct '09

I have a class that provides a shared_ptr number. At the end of the number's life cycle it should be placed back on a list of available numbers. The shared_ptr's custom deleter function looks like what I need. I'm able to get a free function to compile as the deleter just fine. In trying to use a class member function as the custom deleter I've run into compile errors. I'm not sure where I'm going wrong. I know the custom deleter need to be copy constructible and I'm probably breaking some assumed requirement. Any help on what I'm doing wrong would be appreciated. Ryan class CTNGenerator { public: CTNGenerator(void) { m_AvailableCTNs.resize(20); unsigned short startValue = 15; for (ctns::iterator itor = m_AvailableCTNs.begin(); itor != m_AvailableCTNs.end(); ++itor) { //This compiles fine. boost::bind(boost::mem_fun(&CTNGenerator::makeCTNAvailable), this); //Placing the call as the custom delete function doesn't compile. *itor = bus(new unsigned short(startValue++), boost::bind(boost::mem_fun(&CTNGenerator::makeCTNAvailable, this))); } } private: void CTNGenerator::makeCTNAvailable(unsigned short * ctn) { m_AvailableCTNs.push_back(boost::shared_ptr<unsigned short>(ctn)); } private: typedef boost::shared_ptr<unsigned short> bus; typedef std::list<bus> ctns; ctns m_AvailableCTNs; };

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Not able to use multiple cores with boost::asio::ssl
by Ramashish Baranwal 11 Oct '09

11 Oct '09

Hi, I have an application where I am planning to use boost::asio's ssl streams. There are two parts of the app, the initial connection establishment and ssl handshake is done by boost::asio::ssl and the connection is then transferred to the core application which does the the rest. I have written a prototype using multiple threads and io_services similar to io_service_pool example. I am using a dual quad core machine, however I am not able to get the cpu usage beyond one core (i.e. it never exceeds 12-14% in the top) no matter how much the load. On doing some profiling I found that the time taken from socket accept to ssl handshake completion deteriorates linearly with the number of connections without using the other cores. I am not using any explicit locks so expected the application to scale well with the number of cores available. Is is not possible to use multiple cores with boost::asio::ssl libraries or am I not doing it right? A pseudo-code of the app- start connection acceptors handle_accept() { new_conn = new Connection(io_service_pool.get_io_service()); new_conn->start(); } Connection::start() { ssl_socket_.async_handshake(handle_handshake); } Connection::handle_handshake(error) { if (!error) // transfer connection to the application core } Thanks in advance, Ramashish

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[mpl] Syntax error with BOOST_MPL_ASSERT
by Jean-Louis Leroy 11 Oct '09

11 Oct '09

What's wrong with this ? template<class Expected, class T> void check_placeholders(const T&) { BOOST_MPL_ASSERT((is_same<typename T::placeholders, Expected>)); // * } struct Test { typedef int placeholders; }; void f() { check_placeholders<int>(Test()); } msvc9 complains about : error C2059: syntax error : ')' at the line marked with a star. I have put much more complex things inside BOOST_MPL_ASSERT though :-/ I use Boost 1.40. J-L

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[fusion] C arrays in fusion::vector
by Jean-Louis Leroy 11 Oct '09

11 Oct '09

msvc9+fusion 1.40 reject this: fusion::vector<int, char[20]> v; 1>C:\Users\JLL\Documents\Visual Studio 2008\Projects\boost_1_40_0\boost/fusion/container/vector/detail/vector_n.hpp(43) : error C2440: '<function-style-cast>' : cannot convert from 'int' to 'char [20]' 1> There are no conversions to array types, although there are conversions to references or pointers to arrays 1> C:\Users\JLL\Documents\Visual Studio 2008\Projects\boost_1_40_0\boost/fusion/container/vector/detail/vector_n.hpp(42) : while compiling class template member function 'boost::fusion::vector_data2<Derived,T0,T1>::vector_data2(void)' 1> with 1> [ 1> Derived=boost::fusion::vector2<int,char [20]>, 1> T0=int, 1> T1=char [20] 1> ] Am I doing something wrong ? Anyway I can wrap the C array in a class (template)... Thanks, J-L

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[python] Function objects in place of member functions
by Ravi 10 Oct '09

10 Oct '09

Hello, If a free function 'func' has X* as its first argument, then, boost.python allows it to be bound to a member function on the python side, i.e., the following is legal: void func( X* x, arg1_t arg ) { ... } class_<X>( "X" ).def( "func", &func ); In order to use a function object in place of a free function, one must specialize/overload boost::python::detail::get_signature which, for some reason, does not account for function objects. Here's a very simple example that works: ---------------------------------------------- #include <boost/mpl/vector.hpp> struct X { int y; }; // Function object struct Z { int operator()( X *x, int z ) { return z + x->y; } }; namespace boost { namespace python { namespace detail { mpl::vector<int, X*, int> get_signature( Z&, X* ) {return mpl::vector<int, X*, int>();} }}} #include <boost/python/class.hpp> #include <boost/python/module.hpp> BOOST_PYTHON_MODULE( mft ) { boost::python::class_<X>( "X" ) .def( "z", Z() ).def_readwrite( "y", &X::y ); } ------------------------------------------------- However, note that the overload of get_signature precedes the inclusion of the boost.python headers, which is extremely inconvenient. However, if the headers are moved to their proper location as in the following, ---------------------------------------------- #include <boost/mpl/vector.hpp> #include <boost/python/class.hpp> #include <boost/python/module.hpp> struct X { int y; }; // Function object struct Z { int operator()( X *x, int z ) { return z + x->y; } }; namespace boost { namespace python { namespace detail { boost::mpl::vector<int, X*, int> get_signature( Z&, X* ) {return boost::mpl::vector<int, X*, int>();} }}} BOOST_PYTHON_MODULE( mft ) { boost::python::class_<X>( "X" ) .def( "z", Z() ).def_readwrite( "y", &X::y ); } ------------------------------------------------- the compilation fails with the following error message (gcc 4.4.1 with boost 1.37 or 1.39): $ g++ -Wall -shared -o mft.so memft.cc -lboost_python-mt - I/usr/include/python2.6 -fPIC In file included from memft.cc:1: /usr/include/boost/python/class.hpp: In member function ‘void boost::python::class_<T, X1, X2, X3>::def_impl(T*, const char*, Fn, const Helper&, ...) [with T = X, Fn = Z, Helper = boost::python::detail::def_helper<const char*, boost::python::detail::not_specified, boost::python::detail::not_specified, boost::python::detail::not_specified>, W = X, X1 = boost::python::detail::not_specified, X2 = boost::python::detail::not_specified, X3 = boost::python::detail::not_specified]’: /usr/include/boost/python/class.hpp:235: instantiated from ‘boost::python::class_<T, X1, X2, X3>& boost::python::class_<T, X1, X2, X3>::def(const char*, F) [with F = Z, W = X, X1 = boost::python::detail::not_specified, X2 = boost::python::detail::not_specified, X3 = boost::python::detail::not_specified]’ memft.cc:16: instantiated from here /usr/include/boost/python/class.hpp:536: error: no matching function for call to ‘get_signature(Z&, X*)’ Why is the overloaded get_signature not picked up when it is declared *after* the inclusion of the headers? The reason for using function objects is to change the argument types of a member function of X as seen by python; for example, the functor would have an argument type 'double' and would then internally convert the received 'double' argument from the python side into some custom type prior to passing it to the member function of X. In other words, the functor would act as a C++ equivalent of a python decorator. Regards, Ravi

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asio tutorial question on
by Gavin Rogers 09 Oct '09

09 Oct '09

I am going through the tutorial on asio at http://www.boost.org/doc/libs/1_37_0/doc/html/boost_asio/tutorial/tutdaytim… and so far so good. I have a question, the end iterator doesn't seem to be assigned a value, in the examples. I was wondering how does it work.. e.g. tcp::resolver::iterator endpoint_iterator = resolver.resolve(query); tcp::resolver::iterator end; tcp::socket socket(io_service); boost::system::error_code error = boost::asio::error::host_not_found; while (error && endpoint_iterator != end) // <<< Question:here { socket.close(); socket.connect(*endpoint_iterator++, error); } thanks.

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error: expected unqualified id before '=' token
by John Robertson 09 Oct '09

09 Oct '09

The following compiles OK typedef string Colour; struct edge_properties { vector < set< Colour > > eColours; } until I get to template < typename Graph > void populate_arrow_maps(const Graph & g) { typename graph_traits<Graph>::edge_iterator edge_iter, edges_end; typedef vector <set< string > > VCS; typedef vector <set< string > >::iterator vcs_iter, vcs_end; for (tie(edge_iter, edges_end) = edges(g); edge_iter != edges_end; ++edge_iter) { VCS & vcolour_set = get(m_eColours_map, *edge_iter); for(vcs_iter = vcolour_set.begin(); vcs_iter != vcolour_set.end(); ++vcs_iter) { ; } } } Then compiler says error: expected unqualified id before '=' token Referring to the line which is underlined above. So its referring to vcs_iter. Whats wrong? Thanks

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[asio] "bad_descriptor" on async_send_to + socket.close
by Tacheon the Nucleid 09 Oct '09

09 Oct '09

[asio] "bad_descriptor" error on async_send_to + socket.close Hi, I am trying to close a UDP socket on which an async_send_to operation is running. The handler is like this: void Sender::handleSend(error_code const & e, size_t bt) { this_thread::sleep(posix_time::seconds(1)); socket.async_send_to(buffer, remoteEndpoint, bind(&Sender::handleSend, this, placeholders::error, placeholders::bytes_transferred)); } The sender itself is fine. But on some special occasions I have to close the socket. I do it like this: void Sender::do_close() { socket.close(); } void close() { socket.get_io_service().post( bind(&Sender::do_close, this)); } When close() is called, the async handler yields a "bad_descriptor" error. I would expect an "operation_aborted" error as stated in the documentation. For async_receive, everything is fine and works as expected. What am i getting wrong? Greetings, B. Haeberlein -- GRATIS für alle GMX-Mitglieder: Die maxdome Movie-FLAT! Jetzt freischalten unter http://portal.gmx.net/de/go/maxdome01

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[BGL] reset of the random number generator in the sorted_erdos_renyi_iterator
by Marti Cuquet 09 Oct '09

09 Oct '09

Hi, I noticed that when generating several graphs with the sorted_erdos_renyi_iterator with the same random generator all of them happen to be the same. Looking at erdos_renyi_generator.hpp I see that there is a reset in the generator. This does not happens in the normal (unsorted) erdos_renyi_iterator since the generator is passed by reference in the constructor. I'm still not confortable with the BGL and the random libraries, but I might say that it is better to pass the random generator by reference. Is there a special reason for not doing so? Thank you, Martí

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