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networkx.algorithms.reciprocity.reciprocity

reciprocity(G, nodes=None)

Compute the reciprocity in a directed graph.

The reciprocity of a directed graph is defined as the ratio of the number of edges pointing in both directions to the total number of edges in the graph. Formally, \(r = |{(u,v) \in G|(v,u) \in G}| / |{(u,v) \in G}|\).

The reciprocity of a single node u is defined similarly, it is the ratio of the number of edges in both directions to the total number of edges attached to node u.

Parameters:

• G (graph) – A networkx directed graph
• nodes (container of nodes, optional (default=whole graph)) – Compute reciprocity for nodes in this container.

Returns:

out – Reciprocity keyed by node label.

Return type:

dictionary

Notes

The reciprocity is not defined for isolated nodes. In such cases this function will return None.