On 04.04.2016 14:13, Stephen Bonner wrote:
> Hi Tiago,
>
> Thank you for your detailed reply, it cleared things up a lot! I would also 
> like to thank you for your incredible work on graph-tool, its a great package!
>
> Below is the code i now use to count the triangles -
>
>   # number of triangles
> gc = global_clustering(tempG)
> d = tempG.degree_property_map("total")
>     num_triangles = gc[0] * (d.a * (d.a - 1) / 2).sum() / 3
>
> My test dataset is the CA-HepPh network from SNAP - 
> http://snap.stanford.edu/data/ca-HepPh.html
>
> However i am not getting the reported number of triangles for the dataset 
> which, according to SNAP, is - 3,358,499
>
> However from the above graph-tool code i get - 13,434,795
>
> Do you have any idea what might cause the discrepancy between the ground 
> truth and the computed result?

Many SNAP datasets contain parallel edges, but apparently many of their
statistics ignore those. Graph-tool (correctly) incorporates them in the
triangle counting. If you remove the parallel edges (e.g. with
remove_parallel_edges()), you get the same triangle count as reported in
SNAP.

Best,
Tiago

-- 
Tiago de Paula Peixoto <[email protected]>

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