Re: [boost] [BGL] Add edge with vertex' properties instead ofvertex descriptors

From: Wang Weiwei (wwwang_at_[hidden])
Date: 2006-07-15 09:07:55

>
>On Jul 14, 2006, at 10:54 AM, Wang Weiwei wrote:
>
>> Hello,
>>
>> I have a graph type as follows:
>>
>> namespace boost
>> {
>> 	enum vertex_flag_t { vertex_flag = 111 };
>> 	BOOST_INSTALL_PROPERTY(vertex, flag);
>> }
>>
>> typedef boost::adjacency_list<boost::vecS, boost::vecS,  
>> boost::undirectedS,
>> 	property<vertex_name_t, std::string,
>> 		property<vertex_flag_t, bool,
>> 			property<vertex_color_t, default_color_type> > >,
>> no_property> graph_t;
>>
>> graph_t g;
>>
>> That means I want to associate a string as name, a flag, and a  
>> default color to each vertex of my graph,
>> now I want to add edges to my graph directly using the vertex'  
>> properties instead of their descriptors,
>> e.g.
>>
>> boost::add_edge("vertex1", "vertex2", g);
>>
>> How can I accomplish this?
>
>You'll need to create a separate mapping from vertex names to vertex  
>descriptors:
>
>	std::map<std::string, graph_t::vertex_descriptor> name_to_vertex;
>
>	Doug

I've made the following template function to do the jod I want, as indicated by
its name - add vertices using their properties.

template<typename InputPropIterator, typename Graph, 
                typename VertexPropMap>	////
AddVerticesByProp(InputPropIterator first, InputPropIterator last, Graph& g, 
                                  VertexPropMap& pmap,		////
                                  typename std::map<
                                                  typename std::iterator_traits<InputPropIterator>::value_type, 
                                                  typename boost::graph_traits<Graph>::vertex_descriptor
				  >& Prop2VertexMap)	
{
        typedef boost::graph_traits<Graph>::vertex_descriptor vertex_t;
        typedef std::iterator_traits<InputPropIterator>::value_type prop_t;
        typedef std::map<prop_t, vertex_t> prop_vertex_map_t;

        for(; first != last; ++last)
        {
                prop_vertex_map_t::iterator pos;
                bool inserted;
                vertex_t v;
                boost::tie(pos, inserted) = Prop2VertexMap.insert(std::make_pair(*first, vertex_t()));
                if(inserted)
                {
                        v = add_vertex(g);
                        pmap[v] = *first;
                        pos->second = v;
                }
                else
                {
                        v = pos->second;
                }
        }
}

I suppose it could more elegant if one can remove the template param 'VertexPropMap' and the 
corresponding function param 'VertexPropMap& pmap', because the type 'VertexPropMap' is determined
and should be derived (I think) if the other 2 types are given. 

To be clearer, the VertexPropMap is a map from 'typename std::iterator_traits<InputIterator>::value_type'
to 'typename boost::graph_traits<Graph>::vertex_descriptor'.

Similarly, as far as internal property map is concerned, the function param 'pmap' is also determined
and should be derived (I think) from 'g' and type info gien by the InputPropIterator.

What I need now is any help that can eliminate these 2 param's to make the funtion interface not so tedious.

Thanks.

Max