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Re: [Boost-users] How to access bundled properties individually?
by Shufei Fan 22 Feb '07

22 Feb '07

This question is regarding to BGL, I should have included it on the title. Actually, thank goes to Aaron Windsor. From: fansf(a)hotmail.comTo: boost-users(a)lists.boost.orgSubject: How to access bundled properties individually?Date: Thu, 22 Feb 2007 19:39:10 +0000 First, Thank Doug for answering my previous question on parallel edges. Now, my question is:How to access bundled property individually? I defined my graph like this: struct Node{ int label; int mode[3]; //...;};struct Edge{ double nCommBord;}; typedef boost::adjacency_list< boost::setS, boost::vecS, boost::undirectedS, Node, Edge> Graph;but when I want to access property nCommBord of Edge, there seems to be wrong with my property_map type definition. Anyone can point out for me, what is the right version(I cannot seem to find any comment on this kind of usage)? //get edgeWeight propertyproperty_map<Graph, &Edge::nCommBord>::type p_e = get(&Edge::nCommBord, *rowGraph); The error:c:\...\VCProjects\...xxx.cpp(55) : error C2974: 'boost::property_map' : invalid template argument for 'Property', type expected c:\Boost\include\boost-1_33_1\boost\graph\properties.hpp(205) : see declaration of 'boost::property_map'Thanks, Shufei Connect to the next generation of MSN Messenger Get it now! _________________________________________________________________ Explore the seven wonders of the world http://search.msn.com/results.aspx?q=7+wonders+world&mkt=en-US&form=QBRE

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How to access bundled properties individually?
by Shufei Fan 22 Feb '07

22 Feb '07

First, Thank Doug for answering my previous question on parallel edges. Now, my question is: How to access bundled property individually? I defined my graph like this: struct Node{ int label; int mode[3]; //...;};struct Edge{ double nCommBord;}; typedef boost::adjacency_list< boost::setS, boost::vecS, boost::undirectedS, Node, Edge> Graph; but when I want to access property nCommBord of Edge, there seems to be wrong with my property_map type definition. Anyone can point out for me, what is the right version(I cannot seem to find any comment on this kind of usage)? //get edgeWeight propertyproperty_map<Graph, &Edge::nCommBord>::type p_e = get(&Edge::nCommBord, *rowGraph); The error: c:\...\VCProjects\...xxx.cpp(55) : error C2974: 'boost::property_map' : invalid template argument for 'Property', type expected c:\Boost\include\boost-1_33_1\boost\graph\properties.hpp(205) : see declaration of 'boost::property_map' Thanks, Shufei _________________________________________________________________ Connect to the next generation of MSN Messenger http://imagine-msn.com/messenger/launch80/default.aspx?locale=en-us&source=…

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[mpl::math] exponential metafunction for complex types
by Chris Weed 22 Feb '07

22 Feb '07

Hi, I am getting the wrong result for the exponential of complex numbers such as the following: #include <boost/mpl/math/double.hpp> #include <boost/mpl/math/complex_number.hpp> #include <iostream> int main() { typedef boost::mpl::math::string_c_to_double<'-',2,'.',0>::type minus_two; typedef boost::mpl::times<minus_two,boost::mpl::math::pi<boost::mpl::math::double_tag> >::type minus_two_pi; typedef boost::mpl::math::complex_number<double_zero,minus_two_pi> imag_minus_two_pi; std::cout << imag_minus_two_pi() << std::endl; std::cout << boost::mpl::math::exponential<imag_minus_two_pi>::type() << std::endl; return 0; } This prints: 0-6.28319i 1.0329-0.0109834i which should be 0-6.28319i 1.0000-0.00000i Chris

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[multi_index] view with less items than in container possible?
by Boris 22 Feb '07

22 Feb '07

The various indexes of the multi_index_container help to access items in a container differently. Is it also possible to create an index somehow with access to less items in the container? If there is for example a container with employees and I often need to iterate over female employees only is there a way to create an index for this (there could be a bool in the employee class to indicate who is female)? Boris

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boost_1_30_0\boost\crc.hpp(389) : warning C4245: 'initializing' : conversion from 'int' to 'const boost::detail::mask_uint_t<16>::least', signed/unsigned mismatch
by ERIC BERTRAND 22 Feb '07

22 Feb '07

I have this warning on Visual studio 2005. I want to get rid of theses warning. It apperas at line BOOST_STATIC_CONSTANT( least, sig_bits = (~( least(0u) )) ); if I cast (least)(~( least(0u) )) I have not the warning. I want to be sure this is acceptable. Can someone confirm to me? Thanks -- --------------------------------------------------------- erbere erbere(a)gmail.com

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sub_range, assign and permutation_iterator related problem
by abir basak 22 Feb '07

22 Feb '07

Hi, It is an extension to one my previous post, where I needed help while giving access to a sub_range for of an container. In that problem , Mr Thorsten Ottosen, provided answer to all of my queries (Many thanks to him ). This time I am interested to provide indexed access to a vector with a sub_range ,using permutation_iterator. Here some codes are creating problem, while I am using sub_range with permutation iterator. To specify, I am providing a small test code. typedef std::pair<std::size_t,std::size_t> pair_t; template<typename T> class vector_e : private std::vector<T>{ public: typedef vector_e<T> self_type; typedef typename std::vector<T>::iterator iterator; typedef typename std::vector<T>::const_iterator const_iterator; typedef boost::sub_range<self_type> range; typedef boost::sub_range<const self_type> const_range; typedef typename std::vector<T>::size_type size_type; typedef std::vector<int> index_type; typedef typename boost::permutation_iterator<typename iterator,index_type::const_iterator> index_iterator; typedef typename boost::permutation_iterator<typename const_iterator,index_type::const_iterator> const_index_iterator; vector_e() : std::vector<T>(){} using std::vector<T>::begin; using std::vector<T>::end; using std::vector<T>::operator []; using std::vector<T>::insert; index_iterator begin_i(const index_type& i){ return boost::make_permutation_iterator(begin(),i.begin()); } const_index_iterator begin_i(const index_type& i)const{ return boost::make_permutation_iterator(begin(),i.begin()); } index_iterator end_i(const index_type& i){ return boost::make_permutation_iterator(begin(),i.end()); } const_index_iterator end_i(const index_type& i)const{ return boost::make_permutation_iterator(begin(),i.end()); } range get_range(const pair_t& range){ return boost::make_iterator_range(begin()+range.first,begin()+range.second); } const_range get_range(const pair_t& range)const{ return boost::make_iterator_range(begin()+range.first,begin()+range.second); } range get_range(const index_type& i){ return boost::make_iterator_range(boost::make_permutation_iterator(begin(),i.begin()), boost::make_permutation_iterator(begin(),i.end())); } }; int main(int argc,char** argv) { using namespace boost; using namespace boost::assign; using namespace boost::lambda; using boost::lambda::_1; typedef vector_e<int> elem_t; typedef std::vector<int> index_t; elem_t v; int a[] = {00,10,20,30,40,50,60,70,80,90,100}; v.insert(v.end(),a,a+11); const elem_t& cv = const_cast<elem_t&>(v); //v+= 00,10,20,30,40,50,60,70,80,90,100; std::cout<<"original array : "; std::for_each(v.begin(),v.end(),std::cout<<_1<<" "); ///For continuous ranges. elem_t::range r = v.get_range(std::make_pair(1,5)); std::cout<<std::endl<<" range (1,5) : "; ///working fine std::for_each(r.begin(),r.end(),std::cout<<_1<<" "); ///working fine elem_t::const_range cr = v.get_range(std::make_pair(1,5)); std::cout<<std::endl<<" c_range (1,5) : "; std::for_each(cr.begin(),cr.end(),std::cout<<_1<<" "); ///working fine elem_t::const_range cr1 = cv.get_range(std::make_pair(1,5)); std::cout<<std::endl<<" c_range1 (1,5) : "; std::for_each(cr1.begin(),cr1.end(),std::cout<<_1<<" "); index_t i; i+=0,2,6,4,9; std::cout<<std::endl<<" index : "; std::for_each(i.begin(),i.end(),std::cout<<_1<<" "); std::cout<<std::endl<<"index range "; //working fine std::for_each(v.begin_i(i),v.end_i(i),std::cout<<_1 << " "); std::cout<<std::endl<<"c index range "; ///working fine std::for_each(cv.begin_i(i),cv.end_i(i),std::cout<<_1 << " "); ///not working (and its const counter part ) elem_t::range ir = v.get_range(i); } The error it is giving in visual studio 7.1 for sub_range of permutation_iterator is, E:\boost_1_33_1\boost\range\iterator_range.hpp(60): error C2440: 'type cast' : cannot convert from 'boost::range_iterator<C>::type' to 'boost::range_iterator<C>::type' with [ C=const boost::iterator_range<vector_e<int>::index_iterator> ] and [ C=vector_e<int>::self_type ] The questions are 1) Can anyone point out the problem ? (Is sub_range is typed by iterator by any chance, or typed by container only ? ) 2) This is aux question. How to make assign library work for my inherited container (vector_e here ), like the commented line ? any help is appreciated, and thanks to the community . abir -- Abir Basak, Member IEEE Software Engineer, Read Ink Technologies B. Tech, IIT Kharagpur email: abir(a)abirbasak.com homepage: www.abirbasak.com

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[BGL] Dijkstra visitor for examine edge event
by Alejandro Marcos Aragón 22 Feb '07

22 Feb '07

Hi everyone, I posted this message but I haven't received any response so I decided to post it again. I am trying to store all the vertices with their respective distances from a source within the Dijkstra shortest path algorithm. For that I plan to use a std::vector<std::queue > >. I was able to have the visitor working but I don't know how to access to those values that are computed automatically by the algorithm (d_v, d_u, for example). The code I wrote is as follows: template <class Tag> struct vis : public default_dijkstra_visitor { vis() { } template <class Edge, class Graph> void edge_relaxed(Edge e, Graph& g){ cout<<"VISITOR!!!"<<endl; cout<<"Edge -> "<<e<<endl; } private: std::vector<std::queue<Vertex> > storage; }; template <class Tag> vis<Tag> target_visit(Tag) { return vis<Tag>(); } void Dijkstra() { // maps needed by the algorithm IndexMap indexmap = get(vertex_index, *gPtr); WeightMap weightmap = get(edge_weight, *gPtr); // define containers for the predecessor vertices and // for distances std::vector<Vertex> pred(num_vertices(*gPtr)); std::vector<double> dist(num_vertices(*gPtr)); // vertex to compute Dijkstra's algorithm on Vertex source = vertex(get_source(), *gPtr); // Dijkstra's algorithm dijkstra_shortest_paths(*gPtr, source, predecessor_map(&pred[0]).distance_map(&dist[0]).visitor(target_visit(on_examine_edge()))); ... Any help will be appreciated. a^2

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[BGL] merger parallel edges
by Shufei Fan 22 Feb '07

22 Feb '07

Hi, I am new to Boost Graph Library. I have two questions. I defined my graph like this: struct Node{ int label; int mode[3]; //...;}; struct Edge{ double nCommBord;}; typedef boost::adjacency_list< boost::vecS, boost::vecS, boost::undirectedS, Node, Edge> Graph;Somewhere in my program, I construct it using add_edge() method. What I want is, I allow parallel edges, but I all parallel ones being merged(weight summed together). Can I add edges one by one, and use an general method to 'magically' merge them?(is there a function doing merging?) My second question is, where should I find a complete list of usage of all the library methods(say, manual for add_edge) Thanks, Regards, Shufei _________________________________________________________________ Invite your mail contacts to join your friends list with Windows Live Spaces. It's easy! http://spaces.live.com/spacesapi.aspx?wx_action=create&wx_url=/friends.aspx…

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[signals] connection::add_tracked() proposal
by Frank Mori Hess 21 Feb '07

21 Feb '07

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I'd like to propose we add an add_tracked() function to the connection object. This would allow an arbitrary shared_ptr/weak_ptr to be added to the list of objects tracked for the slot. The justification is to allow for situations where an object needed by the slot is not directly owned by a shared_ptr, or doesn't directly correspond to an argument of the bound function. For example, the bound argument might be contained inside another object which is in turn managed by a shared_ptr. We could actually dump boost::track() entirely if we wanted, if we have add_tracked(). - -- Frank -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (GNU/Linux) iD8DBQFF3Gxq5vihyNWuA4URAmS+AJkB3tgE/8p7GlCY+xq+UwfTFjZwigCgoQh0 fgQdVgH73Oh3j1g34HNy+JY= =3UVL -----END PGP SIGNATURE-----

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Serialization newbie question
by Surya Kiran Gullapalli 21 Feb '07

21 Feb '07

Hello all, I'm a newbie to boost serialization and i need some help. I'm using boost serialization, to serialize a class, which contains 3 std::string members. After i serialize i add it to a database. The database I'm using is berkeley-db. The database API needs key/data pair, both in void* type. Now for my problem, the key is std::string, so I'm passing in key as (void *)key.c_str(), I know its crude, but i'm just starting. Now for the data part, I've to serialize the complete class. As, boost::archive::binary_oarchive, takes ostream& as argument for constructor, I've done like this. std::ostringstream os ; boost::archive::binary_oarchive oa (os) ; oa << class_obj ; so the class_obj has been written to os. so i'm sending data to db api as (void *)os.str().c_str(). To retrieve data, I'm using something like this data=db.get_data() ; istringstream is((char *)data) ; boost::archive::binary_iarchive (is) ; The code compiled fine and at run time i'm getting exception basic::string::resize during construction of binary_iarchive. Obviously i was doing wrong. My question is how to serialize data and write it to memory than to a file? and how do i access it again? Thanks in advance, Surya

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