def test_simple_cycle_identification(self):
self.digraph.add_edge(self.a, self.b)
self.digraph.add_edge(self.b, self.a)
quotient = scc.quotient(self.digraph)
nodemap = quotient.nodemap
self.assertEquals(2, len(nodemap))
self.assertTrue(nodemap[self.a] == nodemap[self.b])
self.assertEquals(1, len(quotient.nodes_set()))
self.assertEquals(0, len(quotient.edges()))
def reduce(digraph):
"""
@digraph: Digraph
Returns quotient digraph G' from the digraph G with redundant
edges removed. Check G'.nodemap for mapping of nodes in G to nodes
in G'.
"""
quotient = scc.quotient(digraph)
acyclic_reduce(quotient)
return quotient
def reduce(digraph):
"""
@digraph: Digraph
Returns quotient digraph G' from the digraph G with redundant
edges removed. Check G'.nodemap for mapping of nodes in G to nodes
in G'.
"""
quotient = scc.quotient(digraph)
acyclic_reduce(quotient)
return quotient
def test_edges_between_components(self):
"""
digraph {
A -> B;
B -> A;
B -> C;
B -> E;
C -> D;
D -> C;
D -> E;
}
"""
self.digraph.add_edge(self.a, self.b)
self.digraph.add_edge(self.b, self.a)
self.digraph.add_edge(self.b, self.c)
self.digraph.add_edge(self.b, self.e)
self.digraph.add_edge(self.c, self.d)
self.digraph.add_edge(self.d, self.c)
self.digraph.add_edge(self.d, self.e)
quotient = scc.quotient(self.digraph)
nodemap = quotient.nodemap
self.assertTrue(nodemap[self.a] == nodemap[self.b])
self.assertTrue(nodemap[self.c] == nodemap[self.d])
self.assertTrue(nodemap[self.a] != nodemap[self.c])
self.assertTrue(nodemap[self.e] != nodemap[self.a])
self.assertTrue(nodemap[self.e] != nodemap[self.c])
self.assertEquals(5, len(nodemap))
c1, c2, c3 = nodemap[self.a], nodemap[self.c], nodemap[self.e]
self.assertTrue(quotient.has_edge(c1, c2))
self.assertTrue(quotient.has_edge(c1, c3))
self.assertTrue(quotient.has_edge(c2, c3))
self.assertEquals(3, len(quotient.nodes_set()))
self.assertEquals(3, len(quotient.edges()))
def test_cycle_of_three(self):
"""
digraph {
A -> B;
B -> A;
B -> C;
C -> B;
}
"""
self.digraph.add_edge(self.a, self.b)
self.digraph.add_edge(self.b, self.a)
self.digraph.add_edge(self.b, self.c)
self.digraph.add_edge(self.c, self.b)
quotient = scc.quotient(self.digraph)
nodemap = quotient.nodemap
self.assertEquals(3, len(nodemap))
self.assertTrue(nodemap[self.a] == nodemap[self.b] == nodemap[self.c])
self.assertEquals(1, len(quotient.nodes_set()))
self.assertEquals(0, len(quotient.edges()))
def test_simple_component_with_outgoing_edge(self):
"""
digraph {
A -> B;
B -> A;
B -> C;
}
"""
self.digraph.add_edge(self.a, self.b)
self.digraph.add_edge(self.b, self.a)
self.digraph.add_edge(self.b, self.c)
quotient = scc.quotient(self.digraph)
nodemap = quotient.nodemap
self.assertEquals(nodemap[self.a], nodemap[self.b])
self.assertNotEquals(nodemap[self.c], nodemap[self.a])
c1, c2 = nodemap[self.a], nodemap[self.c]
self.assertEquals(2, len(quotient.nodes_set()))
self.assertEquals(1, len(quotient.edges()))
self.assertTrue(quotient.has_edge(c1, c2))