Returns the two graph-wide clustering coefficients.
The first of these is the average clustering coefficient, the mean of all node local clustering coefficients. The second of these is the transitivity which is 3 times the number of triangles divided by the number of wedges, representing the probability that a randomly chosen wedge is closed as a triangle.
Edges here are treated as undirected, so if the underlying network is directed here, ‘neighbours’ refers to the union of in-neighbours and out-neighbours. ``