Hi all, I've been using the Boost Graph Library for a project that requires the use of the graphviz library, and have run into a quandary. For reasons that are a bit complicated to get into right now, my users need to be able to remove vertices from what are at times extremely large graphs (~75,000 vertices), so vecS is clearly the wrong type for runtime reasons. The problem comes with write_graphviz. As the documentation points out, the graph must have an internal vertex_index property map; listS doesn't have an inherent vertex_index the way vecS does, so I've defined vertex_index as a property (along with vertex_name); the code compiles and runs. However, in the DOT output, I get a vertex list that looks like: 0[label="foo"]; 1[label="bar"]; 2[label="baz"]; [....] and an edge list that looks like 0x8061d90->0x8061db8 [weight="5"]; 0x8061d90->0x8061c50 [weight="13"]; [....] Obviously, the edge list is using vertex descriptors (which in this case end up being the memory location of each vertex object), while the vertex list is using vertex indices (and a quick look at graphviz.hpp confirms this; starting from line 262, the function uses get(vertex_index, *i) to get vertex identifiers for the vertex list in the DOT file, and source(*ei, g) and target(*ei, g) to get source-vertex and target-vertex identifiers for the edge list. This isn't a big deal when the vertex list type is vecS, of course, because vertex-index is basically a pointer into the vector, but it doesn't work for listS, setS, et cetera. Any suggestions for how to resolve this contradiction? I suppose I could try overloading source() and target(), but if there's an easier way to do it, I'd rather go that route. :) Cheers, Meredith L. Patterson