[Boost-users] [BGL] vertices creates new objects

From: George Sakkis (george.sakkis_at_[hidden])
Date: 2007-01-29 00:52:43

I've just started playing with the python bindings of BGL and I'm
puzzled from the following:

>>> from  boost.graph import Graph
>>> g = Graph()
>>> v = g.add_vertex()
>>> g.vertices.next() == v
True
>>> g.vertices.next() is v
False

It seems that the vertices iterator creates new vertex objects every
time instead of iterating over the existing ones. This essentially
prevents, among other things, storing vertices as keys in a dictionary
since the hashes of the stored and the new vertex differ although they
compare equal. Is this really what's happening, and if so, why ?

Thanks,
George