def test_issue_2127(self):
"""Test from issue 2127"""
# Build the example DAG
G = nx.DiGraph()
G.add_edge("A", "C")
G.add_edge("A", "B")
G.add_edge("C", "E")
G.add_edge("C", "D")
G.add_edge("E", "G")
G.add_edge("E", "F")
G.add_edge("G", "I")
G.add_edge("G", "H")
tc = nx.transitive_closure(G)
btc = nx.Graph()
# Create a bipartite graph based on the transitive closure of G
for v in tc.nodes():
btc.add_node((0, v))
btc.add_node((1, v))
for u, v in tc.edges():
btc.add_edge((0, u), (1, v))
top_nodes = {n for n in btc if n[0] == 0}
matching = hopcroft_karp_matching(btc, top_nodes)
vertex_cover = to_vertex_cover(btc, matching, top_nodes)
independent_set = set(G) - {v for _, v in vertex_cover}
assert_equal({'B', 'D', 'F', 'I', 'H'}, independent_set)
def test_issue_2127(self):
"""Test from issue 2127"""
# Build the example DAG
G = nx.DiGraph()
G.add_edge("A", "C")
G.add_edge("A", "B")
G.add_edge("C", "E")
G.add_edge("C", "D")
G.add_edge("E", "G")
G.add_edge("E", "F")
G.add_edge("G", "I")
G.add_edge("G", "H")
tc = nx.transitive_closure(G)
btc = nx.Graph()
# Create a bipartite graph based on the transitive closure of G
for v in tc.nodes():
btc.add_node((0, v))
btc.add_node((1, v))
for u, v in tc.edges():
btc.add_edge((0, u), (1, v))
top_nodes = set([n for n in btc if n[0] == 0])
matching = hopcroft_karp_matching(btc, top_nodes)
vertex_cover = to_vertex_cover(btc, matching, top_nodes)
independent_set = set(G) - set([v for _, v in vertex_cover])
assert_equal(set(['B', 'D', 'F', 'I', 'H']), independent_set)
def test_vertex_cover_issue_3306(self):
G = nx.Graph()
edges = [(0, 2), (1, 0), (1, 1), (1, 2), (2, 2)]
G.add_edges_from([((i, "L"), (j, "R")) for i, j in edges])
matching = maximum_matching(G)
vertex_cover = to_vertex_cover(G, matching)
for u, v in G.edges():
assert u in vertex_cover or v in vertex_cover
def test_unorderable_nodes(self):
a = object()
b = object()
c = object()
d = object()
e = object()
G = nx.Graph([(a, d), (b, d), (b, e), (c, d)])
matching = maximum_matching(G)
vertex_cover = to_vertex_cover(G, matching)
for u, v in G.edges():
assert_true(u in vertex_cover or v in vertex_cover)
def test_unorderable_nodes(self):
a = object()
b = object()
c = object()
d = object()
e = object()
G = nx.Graph([(a, d), (b, d), (b, e), (c, d)])
matching = maximum_matching(G)
vertex_cover = to_vertex_cover(G, matching)
for u, v in G.edges():
assert_true(u in vertex_cover or v in vertex_cover)
def test_vertex_cover_issue_2384(self):
G = nx.Graph([(0, 3), (1, 3), (1, 4), (2, 3)])
matching = maximum_matching(G)
vertex_cover = to_vertex_cover(G, matching)
for u, v in G.edges():
assert_true(u in vertex_cover or v in vertex_cover)
def test_to_vertex_cover(self):
"""Test for converting a maximum matching to a minimum vertex cover."""
matching = maximum_matching(self.graph, self.top_nodes)
vertex_cover = to_vertex_cover(self.graph, matching, self.top_nodes)
self.check_vertex_cover(vertex_cover)
def test_to_vertex_cover(self):
"""Test for converting a maximum matching to a minimum vertex cover."""
matching = maximum_matching(self.graph)
vertex_cover = to_vertex_cover(self.graph, matching)
self.check_vertex_cover(vertex_cover)
def test_vertex_cover_issue_2384(self):
G = nx.Graph([(0, 3), (1, 3), (1, 4), (2, 3)])
matching = maximum_matching(G)
vertex_cover = to_vertex_cover(G, matching)
for u, v in G.edges():
assert_true(u in vertex_cover or v in vertex_cover)
