def connected_component_signature(g):
components = connected_components.compile(g)
component_size = ydict(g)
for v in g.vertices():
c = components(v)
component_size[c] = component_size.setdefault(c,0) + 1
return ydict(g, ((v, component_size[components(v)]) for v in g.vertices()))
def test_all_unique_components(graph):
for v in xrange(100):
graph.add_vertex()
components = connected_components.compile(graph)
recorded_components = set()
for v in graph.vertices():
recorded_components.add(components(v))
assert len(recorded_components) == sum(1 for v in graph.vertices())
def test_straight_line(graph):
for i in xrange(20):
graph.add_edge(i,i+1)
components = connected_components.compile(graph)
recorded_components = set()
for v in graph.vertices():
recorded_components.add(components(v))
assert len(recorded_components) == sum(1 for v in graph.vertices())
def test_undirected_straight_line(graph):
#TODO: would be nice to have some generators for common graphs,
# so that I could just say line_graph here...
for i in xrange(20):
graph.add_edge(i,i+1)
graph.add_edge(i+1,i)
components = connected_components.compile(graph)
recorded_components = set()
for v in graph.vertices():
recorded_components.add(components(v))
assert len(recorded_components) == 1
def test_simple_graph(graph):
# A simple example of strongly connected components
graph.add_edge('a','b')
graph.add_edge('b','c')
graph.add_edge('c','b')
graph.add_edge('c','d')
graph.add_edge('d','b')
graph.add_edge('d','e')
components = connected_components.compile(graph)
assert len(set([components('a'), components('b'), components('e')])) == 3
assert components('b') == components('c')
assert components('c') == components('d')
