[Boost-users] Re: internal properties and subgraphs.

From: Jeffrey Holle (jeff.holle_at_[hidden])
Date: 2004-08-31 17:45:57

I've discovered the local_to_global method family of subgraph.
Just what I needed!

Jeffrey Holle wrote:
> Since I've gotten no answer for these questions yet, thought I'd answer 
> them with my current knowledge.  However be aware that I'm still seeking 
> an answer.  Behond this, since I'm partly guessing, I maybe wrong. 
> Please tell me if so.
> 
> First, it is not possible to access the internal properties of the base 
> graph through a subgraph, using the subgraph's "local" descriptors.
> 
> Second, I assume that this local/global descriptor mapping is whats 
> behind the subgraph's requirement that the base class provide the 
> vertex_index_t and edge_index_t internal properties.
> 
> At this point, I assume that armed with a local vertex descriptor, it 
> will be necessary to do a search through the base graphs vertex_index_t 
> property container with std::find_if.  I am however, not sure that I can 
> get to the global vertex descripter from the iterator that find_if would 
> provide.  Do the property container iterators support the operator- 
> operator?
> 
> Jeffrey Holle wrote:
> 
>> I've been experimenting with subgraphs.
>> At present, they look quite useful in what I'm trying to do, but I've 
>> questions.
>>
>> If I add custom vertex and edge properties to my base graph, can I 
>> access these through a subgraph, using local vertex/edge descriptors?
>>
>> If not, is there a way of obtaining the mapping between global and 
>> local vertex/edge descriptors?