def setUp(self):
self.N = 5
self.G = Graph(self.N)
self.nodes = range(self.N)
self.edges = [
Edge(0, 1),
Edge(0, 2),
Edge(1, 2),
Edge(1, 3),
Edge(1, 4)
]
for node in self.nodes:
self.G.add_node(node)
for edge in self.edges:
self.G.add_edge(edge)
#self.G.show()
node1 = Node(0, 1, "edge")
node2 = Node(0, 2, "edge")
node3 = Node(2, 1, "edge")
node4 = Node(1, 3, "edge")
node5 = Node(1, 4, "edge")
node6 = Node(0, 1, "series", node2, node3)
node7 = Node(0, 1, "parallel", node1, node6)
node8 = Node(0, 1, "jackknife", node7, node4)
node9 = Node(0, 1, "jackknife", node8, node5)
self.root = node9
def make_random_sptree(n):
"""Make a random sp-tree with n vertices."""
if n < 2:
raise ValueError("bad n")
source = 0
sink = n - 1
root = Node(source, sink, "edge")
tnode_list = [root] # na tej liscie maja byc type=edge
node = n - 2
while node > 0:
# Losowanie krawedzi na ktorej bedzie operacja.
i = random.randrange(0, len(tnode_list))
swap(tnode_list, i, -1)
tnode = tnode_list.pop()
# Losowanie operacji.
if tnode.target == sink:
action = random.choice(["series", "parallel", "jackknife"])
else:
action = random.choice(["series", "parallel"])
if action == "series":
tnode.type = "series"
tnode.left = Node(tnode.source, node, "edge")
tnode.right = Node(node, tnode.target, "edge")
tnode_list.append(tnode.left)
tnode_list.append(tnode.right)
elif action == "parallel":
tnode.type = "parallel"
tnode.left = Node(tnode.source, tnode.target, "edge")
tnode.right = Node(tnode.source, tnode.target, "series")
tnode.right.left = Node(tnode.source, node, "edge")
tnode.right.right = Node(node, tnode.target, "edge")
tnode_list.append(tnode.left)
tnode_list.append(tnode.right.left)
tnode_list.append(tnode.right.right)
elif action == "jackknife":
tnode.type = "jackknife"
tnode.left = Node(tnode.source, tnode.target, "edge")
tnode.right = Node(tnode.target, node, "edge")
tnode_list.append(tnode.left)
tnode_list.append(tnode.right)
else:
raise ValueError("bad action")
node -= 1
return root
def prepareSmallGraph2(self):
# 0 s=0, t=1
# |
# 3--1--2
# |
# 4
self.N = 5
self.G = Graph(self.N)
self.nodes = range(self.N)
self.edges = [Edge(0, 1), Edge(1, 2), Edge(1, 3), Edge(1, 4)]
for node in self.nodes:
self.G.add_node(node)
for edge in self.edges:
self.G.add_edge(edge)
# self.G.show()
node1 = Node(0, 1, "edge")
node2 = Node(1, 2, "edge")
node3 = Node(1, 3, "edge")
node4 = Node(1, 4, "edge")
node5 = Node(0, 1, "jackknife", node1, node2)
node6 = Node(0, 1, "jackknife", node5, node3)
node7 = Node(0, 1, "jackknife", node6, node4)
self.root = node7
def find_sptree(graph):
"""Find an sp-tree for an sp-graph."""
if graph.is_directed():
raise ValueError("the graph is directed")
graph_copy = graph.copy()
degree2 = set(node for node in graph.iternodes()
if graph.degree(node) == 2) # active nodes with degree 2
call_stack = []
tnode_dict = dict()
# Etap I. Redukcja grafu do krawedzi lub gwiazdy.
# Dopoki sa wierzcholki stopnia 2 wykonuj odrywanie.
while degree2:
source = degree2.pop()
if graph_copy.degree(source) != 2:
# Czasem stopien wierzcholka moze sie zmniejszyc!
continue
node1, node2 = tuple(graph_copy.iteradjacent(source))
edge = Edge(node1, node2)
if graph_copy.has_edge(edge):
# Jezeli ma krawedz, to trzeba poprawic stopnie wierzcholkow,
# bo przy usuwaniu krawedzi przy source zmniejsza sie stopnie.
if graph_copy.degree(node1) == 3:
degree2.add(node1)
if graph_copy.degree(node2) == 3:
degree2.add(node2)
call_stack.append(("parallel", source, node1, node2))
else: # tu nie trzeba poprawiac stopni
graph_copy.add_edge(edge)
call_stack.append(("series", source, node1, node2))
# Usuwamy krawedzie z source.
graph_copy.del_edge(Edge(source, node1))
graph_copy.del_edge(Edge(source, node2))
# Etap II. Sprawdzamy co zostalo.
degree1 = set(node for node in graph_copy.iternodes()
if graph_copy.degree(node) == 1)
if len(degree1) == 2 and len(call_stack) + 2 == graph.v():
# Zostala jedna krawedz, dodajemy konce do PEO.
node1 = degree1.pop()
node2 = degree1.pop()
root = Node(node1, node2, "edge")
tnode_dict[(node1, node2)] = root
elif len(call_stack) + len(degree1) + 1 == graph.v():
# Zostala gwiazda, jest jackknife.
# Szukam centrum gwiazdy.
for node in graph_copy.iternodes():
deg = graph_copy.degree(node)
if deg > 1:
if deg == len(degree1):
sink = node # centum gwiazdy
break
else:
raise ValueError("not an sp-graph")
# Trzeba ustalic jedno ramie jako koniec, w parze do centrum.
source = degree1.pop()
while degree1:
call_stack.append(("jackknife", degree1.pop(), source, sink))
root = Node(source, sink, "edge")
tnode_dict[(source, sink)] = root
else:
raise ValueError("not an sp-graph")
# Etap III. Budowa sp-tree na bazie call_stack.
while call_stack:
action, node, node1, node2 = call_stack.pop()
if (node1, node2) in tnode_dict:
tnode = tnode_dict[(node1, node2)]
elif (node2, node1) in tnode_dict:
tnode = tnode_dict[(node2, node1)]
else:
raise ValueError("key not in tnode_dict")
if action == "series":
del tnode_dict[(tnode.source, tnode.target)]
tnode.type = "series"
tnode.left = Node(tnode.source, node, "edge")
tnode.right = Node(node, tnode.target, "edge")
tnode_dict[(tnode.source, node)] = tnode.left
tnode_dict[(node, tnode.target)] = tnode.right
elif action == "parallel":
#del tnode_dict[(tnode.source, tnode.target)] # nadpisuje
tnode.type = "parallel"
tnode.left = Node(tnode.source, tnode.target, "edge")
tnode.right = Node(tnode.source, tnode.target, "series")
tnode.right.left = Node(tnode.source, node, "edge")
tnode.right.right = Node(node, tnode.target, "edge")
tnode_dict[(tnode.source, tnode.target)] = tnode.left
tnode_dict[(tnode.source, node)] = tnode.right.left
tnode_dict[(node, tnode.target)] = tnode.right.right
elif action == "jackknife":
#del tnode_dict[(tnode.source, tnode.target)] # nadpisuje
tnode.type = "jackknife"
tnode.left = Node(tnode.source, tnode.target, "edge")
tnode.right = Node(tnode.target, node, "edge")
tnode_dict[(tnode.source, tnode.target)] = tnode.left
tnode_dict[(tnode.target, node)] = tnode.right
else:
raise ValueError("bad action")
#assert all(tnode_dict[key].type == "edge" for key in tnode_dict)
return root
def prepareMediumGraph(self):
# 0_____ s=0, t=8
# | \ \ \
# 1 2 3 4 |
# \ | |/ /
# 5 6 /
# \/ /
# 7 /
# | /
# 8
self.N = 9
self.G = Graph(self.N)
self.nodes = range(self.N)
self.edges = [Edge(0, 2), Edge(0, 3), Edge(0, 4), Edge(0, 8),
Edge(1, 5), Edge(2, 5), Edge(3, 6), Edge(4, 6),
Edge(5, 7), Edge(6, 7), Edge(7, 8)]
for node in self.nodes:
self.G.add_node(node)
for edge in self.edges:
self.G.add_edge(edge)
# self.G.show()
node1 = Node(0, 2, "edge")
node2 = Node(0, 3, "edge")
node3 = Node(0, 4, "edge")
node4 = Node(0, 8, "edge")
node5 = Node(5, 1, "edge")
node6 = Node(2, 5, "edge")
node7 = Node(3, 6, "edge")
node8 = Node(4, 6, "edge")
node9 = Node(5, 7, "edge")
node10 = Node(6, 7, "edge")
node11 = Node(7, 8, "edge")
node12 = Node(0, 5, "series", node1, node6)
node13 = Node(0, 6, "series", node2, node7)
node14 = Node(0, 6, "series", node3, node8)
node15 = Node(0, 6, "parallel", node13, node14)
node16 = Node(0, 5, "jackknife", node12, node5)
node17 = Node(0, 7, "series", node15, node10)
node18 = Node(0, 7, "series", node16, node9)
node19 = Node(0, 7, "parallel", node17, node18)
node20 = Node(0, 8, "series", node19, node11)
node21 = Node(0, 8, "parallel", node20, node4)
self.root = node21