intersection_array

intersection_array(G)

Returns the intersection array of a distance-regular graph.

Given a distance-regular graph G with integers b_i, c_i,i = 0,….,d such that for any 2 vertices x,y in G at a distance i=d(x,y), there are exactly c_i neighbors of y at a distance of i-1 from x and b_i neighbors of y at a distance of i+1 from x.

A distance regular graph’s intersection array is given by, [b_0,b_1,…..b_{d-1};c_1,c_2,…..c_d]

Parameters

G: Networkx graph (undirected)

Returns

b,c: tuple of lists

See also

global_parameters

References

1

Weisstein, Eric W. “Intersection Array.” From MathWorld–A Wolfram Web Resource. http://mathworld.wolfram.com/IntersectionArray.html

Examples

>>> G = nx.icosahedral_graph()
>>> nx.intersection_array(G)
([5, 2, 1], [1, 2, 5])