networkx.algorithms.distance_regular.intersection_array

intersection_array(G)[source]

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

Return type

tuple of lists

Examples

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

References

1

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