Hello,

2010/12/13 Eray Ozkural <examachine@gmail.com>
Oww, is the imperative implementation using hash tables or maps then?

Imperative implementations use hash tables (except the ones called Matrix which use arrays of bitvectors) while persistent implementations use maps.
 
Shouldn't be too hard to plug your own in ocamlgraph if needed.

OcamlGraph is designed for such an use : each algorithm provided by the library is a functor parameterized by the required graph operations (iterators over vertices and edges, ...). Thus you can provide your own in an easy way.

Hope this helps,
Julien Signoles