[Boost-users] [graph] edge_descriptor invalidation

From: Sebastian Weber (sebastian.weber_at_[hidden])
Date: 2008-02-12 03:35:08

Hello everyone!

I'm asking myself, why edge-descriptors become invalid if I remove the
edge and reinsert it? In my case the graph is represented by an
adjacency list with vecS storage for vertices and edges. If I'm not
mistaken, then the edge_descriptor's are just represented by pairs of
vertex indices, right? So why are edge_descriptors invalid if I delete
these edges, reinsert the edges and then want to use the old
edge_descriptors to address those recreated edges? Most interestingly, a
very cumbersome 

edge(source(old_descriptor, graph),
     target(old_descriptor, graph), graph).first

gives me perfectly valid edge_descriptors again after removal and
insertion.

I'm confused.

Thanks for any help in advance.

Sebastian Weber