networkx.s_metric

s_metric(G)

Return the “s-Metric” of graph G: the sum of the product deg(u)*deg(v) for every edge u-v in G

Reference:

@unpublished{li-2005,
 author = {Lun Li and David Alderson and
          John C. Doyle and Walter Willinger},
 title = {Towards a Theory of Scale-Free Graphs:
          Definition, Properties, and  Implications (Extended Version)},
 url = {http://arxiv.org/abs/cond-mat/0501169},
 year = {2005}
 }