estrada_index¶
- estrada_index(G)¶
Return the Estrada index of a the graph G.
Parameters: G (graph) – Returns: estrada index Return type: float Raises : NetworkXError – If the graph is not undirected and simple. See also
estrada_index_exp()
Notes
Let
be a simple undirected graph with
nodes and let
be a non-increasing ordering of the eigenvalues of its adjacency matrix
. The Estrada index is
References
[1] E. Estrada, Characterization of 3D molecular structure, Chem. Phys. Lett. 319, 713 (2000). Examples
>>> G=nx.Graph([(0,1),(1,2),(1,5),(5,4),(2,4),(2,3),(4,3),(3,6)]) >>> ei=nx.estrada_index(G)