[Jung-support] VEPair Class, hashCode and equals required?

[Scott K. <sc...@po...>]

Hi there,

I'm implementing PageRank on an undirected graph with weighted edges.  My
understanding is that because my graph is undirected, the transition
probabilities representing edge weights will be different depending on the
origin vertex.  This makes sense, since the probabilities must total 1 for
the outbound edges of the vertex, but each incident vertex of the edge will
have different requirements, meaning I can't have a common transition
probabilities between them.  (If this understanding is wrong, please
correct me).

So, instead of the first approach to edge weights where I had an edge, v1,
v2, weight, I started playing with VEPair, to see if that would allow me to
implement multiple weights for the same edge depending on the vertex.  But
I'm getting null pointer exceptions in the update method of PageRank
because the call to transform in AbstractIterativeScorer is newing up a new
VEPair, and since there is no hashCode or equals implementation on the
VEPair class, new instances with identical underlying values are not coming
back from the transformer.  If I *don't* key my transformer via VEPairs,
but instead use simpler integers as before, everything works fine.

I can override the required classes to make this work, but I wanted to
check and see if I'm completely on the wrong track, since it seems funny
that VEPair wouldn't be usable in transforms as is.  It's quite possible
that the mistake is on my end.

Thanks a lot.

-- 
Talk to you soon,

Scott Klarenbach

PointyHat Software Corp.
www.pointyhat.ca
p 604-568-4280
e sc...@po...
2404 Guelph Street
Suite A
Vancouver, BC, V5T3P3

_______________________________________
To iterate is human; to recur, divine