After giving up for the first time approximately 1,5
year ago due to so to speak a bit discouraging documentation, for a
couple of weeks I'm trying to work things out with BGL.
I implemented a clustering coefficient calculation algorithm for graphs [
http://emreguney.googlepages.com/clustering_coefficient.hpp
] (only afterwards I discovered that Andrew Sutton has already
implemented one waiting to be deployed). I would really appreciate any
comments&suggestion about the code (quality, missing concept
checks, consistency with genericity of BGL, ...).
While my clustering_coefficient is in trunk, it's not really an official component just yet since the documentation hasn't been merged. Actually I'm supposed to be in the process of converting all of the docs to quickbook, but have had to postpone the work while some fairly large changes come through the pipeline (plus, I'm really busy, otherwise).
Although I thought, this implementation would not work on
AdjacencyMatrix graphs, it works. Therefore, AdjacencyMatrix graphs do
provide adjacent_vertices and out_edges methods. In the documentation
(Graph Concepts page), however, I understand that AdjacencyMatrix Graph
is a refinement of Graph (not IncidenceGraph or AdjacencyGraph) and do
not provide such methods. Am I missing or misinterpreting something?
Concepts don't restrict the interface of a class. A concept only describes what interface is required of a class within a generic algorithm (function template). Just because adjacency_matrix models the AdjacencyMatrix concept, doesn't mean that it can't also be a model of IncidenceGraph (I think it is).
In fact, to tell a dirty secret about the BGL, virtually every graph class and graph adaptor supports the interfaces required by every concept. For example, all graph classes define an edge(u, v, g) overload.