I have been using ocamlgraph for a while, and have been generally  
happy with it.  I experienced some poor performance with moderately  
large graphs (10-100k vertices) recently, which led me to look through  
the source code a little.  It seems that doing anything with the  
predecessors of a vertex, even just getting a list of them, requires  
scanning through all the vertices in a graph.  This seems a little  
crazy to me.  Am I missing something?  Is there some kind of work- 
around that gives reasonable performance for predecessor operations  
(i.e. not O(|V|)).

Thanks,
Ben