# Copyright (C) 2015-2017 by # Aric Hagberg # Dan Schult # Pieter Swart # All rights reserved. # BSD license. """Unit tests for the :mod:`networkx.algorithms.centrality.reaching` module.""" from __future__ import division from nose.tools import assert_almost_equal, assert_equal, raises from unittest import TestCase from networkx import nx class TestGlobalReachingCentrality(TestCase): """Unit tests for the global reaching centrality function.""" @raises(nx.NetworkXError) def test_non_positive_weights(self): G = nx.DiGraph() nx.global_reaching_centrality(G, weight='weight') @raises(nx.NetworkXError) def test_negatively_weighted(self): G = nx.Graph() G.add_weighted_edges_from([(0, 1, -2), (1, 2, +1)]) nx.global_reaching_centrality(G, weight='weight') def test_directed_star(self): G = nx.DiGraph() G.add_weighted_edges_from([(1, 2, 0.5), (1, 3, 0.5)]) grc = nx.global_reaching_centrality assert_equal(grc(G, normalized=False, weight='weight'), 0.5) assert_equal(grc(G), 1) def test_undirected_unweighted_star(self): G = nx.star_graph(2) grc = nx.global_reaching_centrality assert_equal(grc(G, normalized=False, weight=None), 0.25) def test_undirected_weighted_star(self): G = nx.Graph() G.add_weighted_edges_from([(1, 2, 1), (1, 3, 2)]) grc = nx.global_reaching_centrality assert_equal(grc(G, normalized=False, weight='weight'), 0.375) def test_cycle_directed_unweighted(self): G = nx.DiGraph() G.add_edge(1, 2) G.add_edge(2, 1) assert_equal(nx.global_reaching_centrality(G, weight=None), 0) def test_cycle_undirected_unweighted(self): G = nx.Graph() G.add_edge(1, 2) assert_equal(nx.global_reaching_centrality(G, weight=None), 0) def test_cycle_directed_weighted(self): G = nx.DiGraph() G.add_weighted_edges_from([(1, 2, 1), (2, 1, 1)]) assert_equal(nx.global_reaching_centrality(G), 0) def test_cycle_undirected_weighted(self): G = nx.Graph() G.add_edge(1, 2, weight=1) grc = nx.global_reaching_centrality assert_equal(grc(G, normalized=False), 0) def test_directed_weighted(self): G = nx.DiGraph() G.add_edge("A", "B", weight=5) G.add_edge("B", "C", weight=1) G.add_edge("B", "D", weight=0.25) G.add_edge("D", "E", weight=1) denom = len(G) - 1 A_local = sum([5, 3, 2.625, 2.0833333333333]) / denom B_local = sum([1, 0.25, 0.625]) / denom C_local = 0 D_local = sum([1]) / denom E_local = 0 local_reach_ctrs = [A_local, C_local, B_local, D_local, E_local] max_local = max(local_reach_ctrs) expected = sum(max_local - lrc for lrc in local_reach_ctrs) / denom grc = nx.global_reaching_centrality actual = grc(G, normalized=False, weight='weight') assert_almost_equal(expected, actual, places=7) class TestLocalReachingCentrality(TestCase): """Unit tests for the local reaching centrality function.""" @raises(nx.NetworkXError) def test_non_positive_weights(self): G = nx.DiGraph() G.add_weighted_edges_from([(0, 1, 0)]) nx.local_reaching_centrality(G, 0, weight='weight') @raises(nx.NetworkXError) def test_negatively_weighted(self): G = nx.Graph() G.add_weighted_edges_from([(0, 1, -2), (1, 2, +1)]) nx.local_reaching_centrality(G, 0, weight='weight') def test_undirected_unweighted_star(self): G = nx.star_graph(2) grc = nx.local_reaching_centrality assert_equal(grc(G, 1, weight=None, normalized=False), 0.75) def test_undirected_weighted_star(self): G = nx.Graph() G.add_weighted_edges_from([(1, 2, 1), (1, 3, 2)]) centrality = nx.local_reaching_centrality(G, 1, normalized=False, weight='weight') assert_equal(centrality, 1.5)