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Re: [Boost-users] Usingboost::serializationinreal-timewithoutallocating memory
by Brian Wood 22 Sep '09

22 Sep '09

Stefan Strasser writes: > sure, it's the best serialization solution I know and the template > technique trumps any reflection based solution (even if c++ had > reflection). In what way? The "Usage" section of this page, http://webEbenezer.net/comparison.html<http://webebenezer.net/comparison.html>, gives an example of how it's possible to produce a cleaner solution than that afforded by the Boost Serialization library. The Ebenezer approach to the bus_stop example is twelve lines less than the Boost Serialization approach. Regards, Brian Wood www.webEbenezer.net <http://www.webebenezer.net/> "Then Samuel took a rock and set it up between Mizpah and Shen. He named it Ebenezer [Rock of Help] and said, 'Until now the L-RD has helped us.'"

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boost::proto user guide - compile error creating a lazy function
by Tom Babbin 21 Sep '09

21 Sep '09

Hi, I am going through proto user guide. I am getting compiling error for the following piece code (it's pretty much copy and pasted from the guide). I used 1.40 and gcc. #include <iostream> #include <boost/mpl/int.hpp> #include <boost/proto/core.hpp> #include <boost/proto/context.hpp> #include <boost/proto/debug.hpp> #include <cmath> #include <vector> namespace proto = boost::proto; template<int I> struct placeholder {}; // Define some placeholders proto::terminal< placeholder< 1 > >::type const _1 = {{}}; proto::terminal< placeholder< 2 > >::type const _2 = {{}}; struct calculator_context : proto::callable_context< calculator_context const > { // Values to replace the placeholders std::vector<double> args; // Define the result type of the calculator. // (This makes the calculator_context "callable".) typedef double result_type; // Handle the placeholders: template<int I> double operator()(proto::tag::terminal, placeholder) const { return this->args[I]; } }; // Define a pow_fun function object template<int Exp> struct pow_fun { typedef double result_type; double operator()(double d) const { return std::pow(d, Exp); } }; // Define a lazy pow() function for the calculator DSEL. // Can be used as: pow< 2 >(_1) template<int Exp, typename Arg> typename proto::function< typename proto::terminal<pow_fun<Exp> >::type , Arg const & >::type pow1(Arg const &arg) { typedef typename proto::function< typename proto::terminal<pow_fun<Exp> >::type , Arg const & >::type result_type; result_type result = {{{}}, arg}; return result; } int main() { calculator_context ctx; ctx.args.push_back(3); std::cout << boost::proto::eval( pow1<2>( _1 ), ctx ); return 0; } The error says: calc2.cpp: In function 'int main()': calc2.cpp:116: error: no matching function for call to 'eval(boost::proto::exprns_::expr<boost::proto::tag::function, boost::proto::argsns_::list2<boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<pow_fun<2> >, 0l>, const boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<placeholder<1> >, 0l>&>, 2l>, calculator_context&)' /auto/cigprod/spg/lx86_64/opt/boost_1_40_0/boost/proto/eval.hpp:91: note: candidates are: typename boost::proto::result_of::eval<Expr, Context>::type boost::proto::eval(Expr&, Context&) [with Expr = boost::proto::exprns_::expr<boost::proto::tag::function, boost::proto::argsns_::list2<boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<pow_fun<2> >, 0l>, const boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<placeholder<1> >, 0l>&>, 2l>, Context = calculator_context] /auto/cigprod/spg/lx86_64/opt/boost_1_40_0/boost/proto/eval.hpp:100: note: typename boost::proto::result_of::eval<Expr, Context>::type boost::proto::eval(Expr&, const Context&) [with Expr = boost::proto::exprns_::expr<boost::proto::tag::function, boost::proto::argsns_::list2<boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<pow_fun<2> >, 0l>, const boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<placeholder<1> >, 0l>&>, 2l>, Context = calculator_context] Thanks. -- View this message in context: http://www.nabble.com/boost%3A%3Aproto-user-guide---compile-error-creating-… Sent from the Boost - Users mailing list archive at Nabble.com.

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[graph] : newbie question on brandes_betweenness_centrality
by Matthew Walker 21 Sep '09

21 Sep '09

Hi, I am very much a newbie at this and would greatly appreciate some help on how I could get the brandes_betweenness_centrality function to work for me. I have the following code that compiles without error, but seg faults when I run it: #include <map> #include <boost/graph/graph_traits.hpp> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/graph_utility.hpp> #include <boost/graph/betweenness_centrality.hpp> #include <boost/graph/exterior_property.hpp> int main() { ... // I am reading a network from a file and storing it into lEdges and lNumVertices typedef adjacency_list<vecS, vecS, undirectedS > Graph; Graph g(lEdges.begin(), lEdges.end(), lNumVertices); typedef boost::exterior_vertex_property<Graph, float> BetweennessProperty; typedef BetweennessProperty::map_type BetweennessMap; BetweennessMap lMap; brandes_betweenness_centrality(g, lMap); } If I could get this to work, I then have aspirations that the helper function central_point_dominance(g, lMap) might give me the betweenness centralization measure that I'm after. Thanks in advance for your help! Matthew

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Hierarchical enumeration?
by Archie14 21 Sep '09

21 Sep '09

Does boost (or any other lib in C++) have facility to support smth that resembles hierarchical enumeration? I would like to have something like the following: enum Hierarchy { Store::Clothing = 1 Store::Electronics, Building::Residential, Building::Commercial } ... Hierarchy h = Hierarchy::Building::Commercial; ... if (h == Hierarchy::Store) { if (h == Hierarchy::Store::Clothing) std::cout<<"clothing"; } ...

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ASIO newbie: Passing parameters from a TCP client to a server
by Ramon F Herrera 21 Sep '09

21 Sep '09

Hello all, I have studying the ASIO examples, and experimenting with them. Still, I could benefit from the guidance of experienced programmers. This is my first client-server set of apps. I need the client to pass a few arguments to the server, lets say four. Should I pass them in 4 different lines? Being synchronous I suppose the client blocks until the server performs a read? (that seems to be what I am seeing now). I heard that there are ways to attach the debugger (gdb) to a server process when it starts? (that feat seems to be major wizardry). Sample code would be very appreciated. TIA, -Ramon

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[fusion] transform a heterogeneous vector
by Jean-Louis Leroy 20 Sep '09

20 Sep '09

In the example from the documentation : struct triple { typedef int result_type; int operator()(int t) const { return t * 3; }; }; ... assert(transform(make_vector(1,2,3), triple()) == make_vector(3,6,9)); ...all the elements have the same type. How can it work with heterogeneous vectors ? What would be typedef'ed to result_type ? Jean-Louis

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Can Regex callback function arguments be modified?
by Ramon F Herrera 20 Sep '09

20 Sep '09

I am having some trouble with the Regex callback architecture. Fist of all for, for a variable number of matches, the only way to code is with a callback function and for_each iterator, correct? To make it more interesting, I have a callback calling another callback. This could obviously go deeper and deeper. Due to the inflexibility (perhaps by me perceived?) of the callback architecture, I am forced to use a lot of global variables. To be fair, this is highly manageable within my current application, but I am concerned that this "implicit number and types of parameters" restriction may become a stumbling block in future code. At this stage, what I am trying to determine whether I should base my program(s) on (from simplest to more complex): - Regex - eXpressive - Spirit So far, I prefer Regex because it is much more stable than Spirit. The latter seems to have great potential, but when when I find that I am unable to even build the test examples properly, and the specs vary from one version to the next, I conclude that it is best to allow the good people of Spirit ("spirited people"? :-) time to deliver a more polished product. Don't know anything about eXpressive yet. Regards, -Ramon

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[Test] How to treat memory leaks as errors?
by Василий Старостин 19 Sep '09

19 Sep '09

Hi! I use Boost.Test as testing facility and get "memory leak detected" messages every time this happens. And this is good. However, Boost.Test doesn't return non-zero error code when leaks detected (as it does this when tests fail). How can I make my testing program to return non-zero error code if memory leaked? WBR, Vasily

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How to find Boost 1.40.0 with cmake 2.6?
by Ingolf Steinbach 19 Sep '09

19 Sep '09

Hi, maybe this is a bit off-topic as it is probably a cmake problem, but it could turn out that the correct solution also involves suitable invocation of bjam. As there seems to be no Windows/VC9.0 installer for Boost 1.40.0 (yet), I have built and installed the libraries myself as follows: ...\boost_1_40_0> bootstrap ...\boost_1_40_0> .\bjam --prefix=C:\Programme\boost\boost_1_40_0 ...\boost_1_40_0> .\bjam --prefix=C:\Programme\boost\boost_1_40_0 install Now, there is the following tree in C:\Programme\boost: C:\Programme\boost +-boost_1_40_0 +-include | +-boost-1_40 | +-boost | +.... +-lib +-libboost....-vc90-mt-1_40.lib +-... What is the correct way to teach the FindBoost module in cmake where to search for the boost installation? I have found that I need to at least set(Boost_ADDITIONAL_VERSIONS "1.40" "1.40.0") However, cmake does not yet find Boost. According to the debugging output of the module, the situation seems to improve slightly when I additionally specify set(BOOST_ROOT C:/Programme/boost) Now, cmake reports "Boost version: 1.40.0" but does not find any libraries. Would I have to supply different options to bjam in order to find the libraries? Is it possible to avoid having to specify BOOST_ROOT in the CMakeLists.txt file? TIA for your support! Ingolf

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Mersenne twister problem
by ruya 19 Sep '09

19 Sep '09

Hello I've built a meta-heuristics library in which I use the boost random library. I am using several independent generators through the application. The problem is in the core of my library. The tricky part is that I have three different algorithms using the core, all of them using the class where a segmentation fault happens, but only one of them crashes when it tries to use the class, the others run as expected. Gdb points to the boost library, as you can see in the snippet bellow. I couldn't find any information on this issue, and I cannot see something wrong with my code (the relevant part is bellow). The parent class where generators are declared: template< class SType, typename MemP > class SearchFunctor{ (...) public: virtual SPtr operator()( SPtr s, int iter ) = 0; SearchFunctor(){ (...) //This is how I initialize teh generators, being MASTER SEED 666 generator1 = base_generator_type(MASTER_SEED*13); uni_dist1 = boost::uniform_real<>(0,1); uniEmp = new GeneratorI(generator1, uni_dist1); generator2 = base_generator_type(MASTER_SEED*17); uni_dist2 = boost::uniform_real<>(0,1); uniRes = new GeneratorI(generator2, uni_dist2); } protected: base_generator_type generator1, generator2; boost::uniform_real<> uni_dist1, uni_dist2; GeneratorI* uniEmp; GeneratorI* uniRes; }; The derived class using the generators: template< class SType, typename MemP > struct SwapSearch : public SearchFunctor<SType,MemP>{ typedef SearchFunctor<SType,MemP> Parent; (...) SPtr operator()( SPtr s, int iter ){ assert(s != NULL); assert(s->GetDomain()!= NULL); assert(s->GetDomain()->GetTotalEntities()>1); (...) d1 = (*Parent::uniEmp)() * (s->GetDomain()->GetTotalEntities()-1); d2 = (*Parent::uniEmp)() * (s->GetDomain()->GetTotalEntities()-1); (...) return 0; } }; The output of the debugger has a lot of lines because of meta-programming but starts and finishes with this: #0 0x08071a57 in brickheuristics::SwapSearch (...) (...) at /usr/include/boost/random/mersenne_twister.hpp:279 279 UIntType z = x[i]; Thanks -- View this message in context: http://www.nabble.com/Mersenne-twister-problem-tp25382114p25382114.html Sent from the Boost - Users mailing list archive at Nabble.com.

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