Hi Thom, 2006/11/8, Thom DeCarlo <t.r.decarlo@larc.nasa.gov>:
I have a couple of n00b questions. I have constructed a BGL graph that uses the edge_name_t property to road names. I want to change the weights of some of the roads based on input from the user. Is there a way to set up an iterator to step through edges that have names which match elements of a set? (e.g., "A,B,B1,L,M")
In a related question, I need to extract a vertex whose vertex_index_t value matches a specific value. The vertices were not entered in any specific order, so the "vertex(1, g)" function returns the first vertex to have been entered into the graph, but not necessarily the one whose index value is "1".
If I don't get you wrong, there's no direct way in the BGL to do that. The properties you attach to a vertex or an edge are normally accessed through the edge or vertex descriptor respectively. What you want to do is the other way around. Get from a property to the edge desciptor(s) that match that property or in the case of vertex_index to the vertex descriptor. Maybe you can use Bimap (http://tinyurl.com/y95qng), where you can get keys (edge/vertex-descriptors) from values together with the concept of exterior property maps (http://tinyurl.com/yhju58) and Constructing an Exterior Property Map. Reading further in the Bimap docs, I think I found what you want: http://tinyurl.com/yxzpme HTH, Stephan