<snip> > > > > I'm using customized-internal properties that do not have 'color' > > information. Now, algorithms (undirected_dfs() for example) need to map > > each vertex and edge to its respective color, so in the previous case, the > > maps must be passed as arguments to the algorithms (OTOH, if I were using > > color_maps for both vertex and edge internal properties, the > > bgl_named_params<> version of the function would do the job, and I wouldn't > > care about the mapping.) That's what I meant when I said that having > > internal properties requires the mapping . > > Understood. You can't attach vertex_color like adjacency_list class allows, > right?
No, because that template parameter was already taken by my custom-property. <snip> > > You're right. Did you overload add_vertex() and/or add_edge() functions to > > receive the 'property' container or a std::back_insert_iterator (pointing > > to the prop. cont.)? > > No, I've made the [] method of property map resize the underlying vector if > index is out of range. Quite simple. That'll be for vertex_map. If one's using std::map<> as the edge-color-map, no more actions are needed because the value is simply stored in the map if the key doesn't exist. <snip> > Rereading my sentence, I understand that is was poorly worded. I meant that I > should be able to create, for every kind of graph, external property map that > will work without requiring me to manually assign indices. That'd be nice! > > > >Specifically, for all graphs both vertex_descriptor and > > > edge_descriptor should be comparable, so that you can use map directly. > > > > Can you tell me more about this? AFAIK, vertex_descriptor is of type size_t > > (vecS) and edge_descriptor is of type ::boost::detail::edge_base<>. > > I meant that > std::map< typename graph_traits<G>::vertex_descriptor>, int> > and > std::map< typename graph_traits<G>::edge_descriptor>, int> Is here 'int' the index of the vertex/edge container? > > should always work, regardless of the type 'G'. size_t will work now (although > inefficient). But edge_base<> is not comparable, so it won't work. I think > it should have operator< That would be nice. Then I could create a map like: std::map<typename graph_traits<G>::edge_descriptor, default_color_type> as an external edge-color-map, without the need of put() and get() overloading. I think that's the best solution! Specifically, if line 688 of boost/boost/graph/detail/adjacency_list.hpp would have returned : this->m_source < other.m_source || (!(other.m_source < this->m_source) && this->m_target < other.m_target), then edge mapping would have been simpler. <snip> > I think that edge_descriptor should contain edge index inside it. When you > create new edge, the next free index is allocated from a list of free indices > (or num_edges(g) is used). When you delete edge, it's index is added to > the list of free indices. This design requires one extra int per edge, plus > the store of free indices --- the max number of edges graph ever had, > in the worsts case, but probably quite little in practice. What's the advantage to have an edge-index stored? The only one that comes to my mind is to use it as edge-container index; however, if this is the case, all indeces should be updated every time an edge is added or deleted. > > > > In both cases, you should be able to write > > > > > > edge_property_map<G, int>::type pm; > > > > > > and have it work. What do you think? > > > > AFAIK, that's for internal properties. Please correct me if I'm wrong. > > I don't know what this syntax does now :-) I mean that this or similiar syntax > should be used to find the type suitable for external property map. > > > > I think that external property maps should be improved, like I describe > > > > above > > > > > or it some other way. It hits me quite often. > > > > I guess you're refering to the documentation; if that's the case, I agree. > > Documentation hits me too. But I would also like to be able to provide > external properties for edges easily. <snip> Agree completely! > > - Volodya > _______________________________________________ > Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost > vladimir josef sykora morphochem AG gmunder str. 37-37a 81379 muenchen tel. ++49-89-78005-0 fax ++49-89-78005-555 [EMAIL PROTECTED] http://www.morphochem.de _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
