Return communicability betweenness for all pairs of nodes in G.
Communicability betweenness measure makes use of the number of walks connecting every pair of nodes as the basis of a betweenness centrality measure.
Parameters :  G: graph : 

Returns :  nodes:dictionary :

Raises :  NetworkXError :

See also
Notes
Let be a simple undirected graph with nodes and edges, and denote the adjacency matrix of .
Let be the graph resulting from removing all edges connected to node but not the node itself.
The adjacency matrix for is , where has nonzeros only in row and column .
The communicability betweenness of a node is [R135]
where is the number of walks involving node r, is the number of closed walks starting at node and ending at node , and is a normalization factor equal to the number of terms in the sum.
The resulting takes values between zero and one. The lower bound cannot be attained for a connected graph, and the upper bound is attained in the star graph.
References
[R135]  (1, 2) Ernesto Estrada, Desmond J. Higham, Naomichi Hatano, “Communicability Betweenness in Complex Networks” Physica A 388 (2009) 764774. http://arxiv.org/abs/0905.4102 
Examples
>>> G = nx.Graph([(0,1),(1,2),(1,5),(5,4),(2,4),(2,3),(4,3),(3,6)])
>>> cbc = nx.communicability_betweenness_centrality(G)