On Apr 28, 2009, at 3:40 PM, Lindley M French wrote:

Here's my problem. I've got a very large graph (say a few thousand nodes). This graph is planar, although that doesn't really affect much.

Small clusters of vertices are grouped into "regions". The edges within a region are marked as "on", and those between regions are marked as "off".

I need to be able to pull all vertices from a region and some or all of its neighboring regions, as well as all induced edges, into a local graph that I do work on.

At first I thought of using the subgraph function together with copy_graph, but the subgraph interface is pretty unintuitive, so I'm avoiding it for now.

I have a mechanism to iterate over all the vertices in a region, but not the edges. How can I get an iterator to the edges around a given vertex or set of vertices? adjacency_iterator isn't the right tool. Is there an exhaustive list of all iterators available in BGL somewhere?

The function out_edges(u, g) returns an iterator range for the edges around a vertex (all incident edges for an undirected graph, just out_edges for a directed graph), for a graph that models the IncidenceGraph concept: http://www.boost.org/doc/libs/1_38_0/libs/graph/doc/IncidenceGraph.html The "graph concepts" document what interfaces define a concept: http://www.boost.org/doc/libs/1_38_0/libs/graph/doc/graph_concepts.html Individual graph classes, like the adjacency_list class template, document what concepts they "model", and individual graph algorithms document which concepts they require, for example: http://www.boost.org/doc/libs/1_38_0/libs/graph/doc/adjacency_list.html http://www.boost.org/doc/libs/1_38_0/libs/graph/doc/ kruskal_min_spanning_tree.html Personally, I find the book "The Boost Graph Library: User Guide and Reference Manual" essential for an overview, even if it is getting a bit dated. -- Michael