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"""Functions for computing the harmonic centrality of a graph.""" | |
from functools import partial | |
import networkx as nx | |
__all__ = ["harmonic_centrality"] | |
def harmonic_centrality(G, nbunch=None, distance=None, sources=None): | |
r"""Compute harmonic centrality for nodes. | |
Harmonic centrality [1]_ of a node `u` is the sum of the reciprocal | |
of the shortest path distances from all other nodes to `u` | |
.. math:: | |
C(u) = \sum_{v \neq u} \frac{1}{d(v, u)} | |
where `d(v, u)` is the shortest-path distance between `v` and `u`. | |
If `sources` is given as an argument, the returned harmonic centrality | |
values are calculated as the sum of the reciprocals of the shortest | |
path distances from the nodes specified in `sources` to `u` instead | |
of from all nodes to `u`. | |
Notice that higher values indicate higher centrality. | |
Parameters | |
---------- | |
G : graph | |
A NetworkX graph | |
nbunch : container (default: all nodes in G) | |
Container of nodes for which harmonic centrality values are calculated. | |
sources : container (default: all nodes in G) | |
Container of nodes `v` over which reciprocal distances are computed. | |
Nodes not in `G` are silently ignored. | |
distance : edge attribute key, optional (default=None) | |
Use the specified edge attribute as the edge distance in shortest | |
path calculations. If `None`, then each edge will have distance equal to 1. | |
Returns | |
------- | |
nodes : dictionary | |
Dictionary of nodes with harmonic centrality as the value. | |
See Also | |
-------- | |
betweenness_centrality, load_centrality, eigenvector_centrality, | |
degree_centrality, closeness_centrality | |
Notes | |
----- | |
If the 'distance' keyword is set to an edge attribute key then the | |
shortest-path length will be computed using Dijkstra's algorithm with | |
that edge attribute as the edge weight. | |
References | |
---------- | |
.. [1] Boldi, Paolo, and Sebastiano Vigna. "Axioms for centrality." | |
Internet Mathematics 10.3-4 (2014): 222-262. | |
""" | |
nbunch = set(G.nbunch_iter(nbunch)) if nbunch is not None else set(G.nodes) | |
sources = set(G.nbunch_iter(sources)) if sources is not None else G.nodes | |
spl = partial(nx.shortest_path_length, G, weight=distance) | |
centrality = {u: 0 for u in nbunch} | |
for v in sources: | |
dist = spl(v) | |
for u in nbunch.intersection(dist): | |
d = dist[u] | |
if d == 0: # handle u == v and edges with 0 weight | |
continue | |
centrality[u] += 1 / d | |
return centrality | |