def add_edge(self, vertex1, vertex2, cost):
exception_message = ""
if self.is_edge(vertex1, vertex2):
exception_message += "The edge from vertex1 to vertex 2 already exists"
if len(exception_message) > 0:
raise exceptionGraph(exception_message)
self.__dictionaryOut[vertex1].append(vertex2)
self.__dictionaryIn[vertex2].append(vertex1)
self.__dictionaryCosts[(vertex1, vertex2)] = cost
def remove_vertex(self, vertex):
if vertex not in self.parse_keys():
raise exceptionGraph("Vertex doesn't exist")
for vertex2 in self.__dictionaryOut[vertex]:
self.__dictionaryIn[vertex2].remove(vertex)
del self.__dictionaryCosts[(vertex, vertex2)]
for vertex2 in self.__dictionaryIn[vertex]:
self.__dictionaryOut[vertex2].remove(vertex)
del self.__dictionaryCosts[(vertex2, vertex)]
del self.__dictionaryOut[vertex]
del self.__dictionaryIn[vertex]
def __loadFromFile(self):
try:
with open(self.__fileName, "r") as file:
first_line = file.readline()
first_line = first_line.strip().split()
vertices, edges = int(first_line[0]), int(first_line[1])
self.__Graph = Graph(vertices)
for i in range(edges):
line = file.readline()
line = line.strip().split()
vertex1, vertex2, cost = int(line[0]), int(line[1]), int(line[2])
self.__Graph.add_edge(vertex1, vertex2, cost)
print("Graph loaded")
except IOError:
raise exceptionGraph("Error while reading file")
def add_vertex(self, vertex):
if vertex in self.parse_keys():
raise exceptionGraph("This vertex already exists in the graph")
self.__dictionaryOut[vertex] = []
self.__dictionaryIn[vertex] = []
def is_edge(self, vertex1, vertex2):
try:
return vertex2 in self.__dictionaryOut[vertex1]
except KeyError:
raise exceptionGraph(
"No edge between these 2 vertices in the graph")
def parse_in_neighbours(self, vertex):
try:
return list(self.__dictionaryIn[vertex])
except KeyError:
raise exceptionGraph("Inexistent vertex")
def change_edge_cost(self, vertex1, vertex2, cost):
if (vertex1, vertex2) in self.__dictionaryCosts:
self.__dictionaryCosts[(vertex1, vertex2)] = cost
else:
raise exceptionGraph("The edge doesn't exist")
def get_in_degree(self, vertex):
try:
return len(self.__dictionaryIn[vertex])
except KeyError:
raise exceptionGraph("The vertex doesn't exist")
def remove_edge(self, vertex1, vertex2):
if not self.is_edge(vertex1, vertex2):
raise exceptionGraph("This edge doesn't exist")
del self.__dictionaryCosts[(vertex1, vertex2)]
self.__dictionaryOut[vertex1].remove(vertex2)
self.__dictionaryIn[vertex2].remove(vertex1)
def validator_negative_costs(self, matrix):
for vertex1 in range(self._vertices):
for vertex2 in range(self._vertices):
if matrix[vertex1][vertex2] + matrix[vertex2][vertex1] < 0:
raise exceptionGraph("It has negative cost cycles!")
'''