def test_get_edge(self):
g = DiGraph()
for i in range(7):
g.add_node(i)
g.add_edge(1, 1, 3)
g.add_edge(1, 2, 4)
g.add_edge(1, 6, -8)
g.add_edge(2, 1, 7)
g.add_edge(2, 1, 9)
g.add_edge(4, 1, 4)
g.add_edge(32, 1, 4)
g.add_edge(5, 1, 4)
g.add_edge(5, 1, 3)
g.add_edge(3, 1, 3)
g.remove_node(3)
g.add_edge(6, 1, 3)
g.remove_edge(6, 1)
self.assertIsNone(g.get_edge(6, 1))
self.assertIsNone(g.get_edge(6, 6))
self.assertIsNone(g.get_edge(4, 5))
self.assertIsNone(g.get_edge(3, 9))
self.assertEqual(g.get_edge(1, 2), 4)
self.assertEqual(g.get_edge(2, 1), 7)
class GraphAlgo:
def __init__(self, d_graph=None):
if d_graph is None:
self.g = DiGraph()
else:
self.g = d_graph
# method to return the DiGraph
def get_graph(self):
return self.g
# method which crate a graph from a json format file and then init the graph in the AlgoGraph
def load_from_json(self, file_name: str):
if self is None:
return False
new_graph = DiGraph()
try:
with open(file_name, 'r') as fp:
jsn = json.load(fp)
for item in jsn['Nodes']:
new_graph.add_node(item.get('id'))
if item.get('pos') is not None:
pos = item.get('pos')
x, y, z = pos.split(',')
x = float(x)
y = float(y)
z = float(z)
new_graph.get_node(item.get('id')).pos = (x, y, z)
for edge in jsn['Edges']:
src = edge['src']
dest = edge['dest']
w = edge['w']
new_graph.add_edge(src, dest, w)
self.g = new_graph
except:
print('cant open file')
return False
return True
# method which saves the DiGraph in a json format
def save_to_json(self, filename):
if self is None or self.g is None:
return False
x = []
y = []
try:
for value in self.g.get_all_v().values():
if value.pos is None:
x.append({"id": value.id})
else:
s, t, u = value.pos
str_pos = str(s) + ", " + str(t) + ", " + "0.0"
x.append({"id": value.id, "pos": str_pos})
for value in self.g.get_all_v().values():
for sec_key, sec_val in self.g.all_out_edges_of_node(value.id).items():
y.append({"src": value.id, "dest": sec_key, "w": sec_val})
w = {}
w["Nodes"] = x
w["Edges"] = y
with open(filename, 'w') as json_file:
json.dump(w, json_file)
except:
print('Eror saving file')
return False
return True
# method to calculate the shortest path between to nodes using Dijikstra algorithm with a priorityqueue
# that use a comparator of the value W of every node
# the function retrun a tuple with the lentgh of the path and a list with all the nodes of the shortest path
# the method also uses the value Tag of node class to check if a node was visited or not
def shortest_path(self, id1: int, id2: int) -> (float, list):
if self is None or self.g is None:
return (float('inf'), [])
if self.g.get_node(id1) is None or self.g.get_node(id2) is None:
return (float('inf'), [])
if id1 == id2:
return (0, [id1])
for node in self.g.get_all_v().values():
node.w = -1
node.tag = 0
q = queue.PriorityQueue()
dict_node = {}
node = self.g.get_node(id1)
node.w = 0
q.put(node)
while not q.empty():
node = q.get()
node.tag = 1
ni_list = self.g.all_out_edges_of_node(node.id)
for ni_node in ni_list.keys():
if self.g.get_node(ni_node).tag == 0:
sum = node.w + self.g.get_edge(node.id, ni_node)
if sum < self.g.get_node(ni_node).w or self.g.get_node(ni_node).w == -1:
self.g.get_node(ni_node).w = sum
dict_node[ni_node] = node.id
q.put(self.g.get_node(ni_node))
arr_list = []
if self.g.get_node(id2).w == -1:
return (float('inf'), [])
else:
prev_node = id2
arr_list.append(prev_node)
prev_node = dict_node.get(prev_node)
while prev_node != id1:
arr_list.append(prev_node)
prev_node = dict_node.get(prev_node)
arr_list.append(id1)
arr_list.reverse()
tuple_list = (self.g.get_node(id2).w, arr_list)
return tuple_list
# a method that recive a node id and return the biggest strongly component of the node
# the method use the "naive algorithm" and run a DFS from the given node after that we call
# the method reverse graph wich revers all the edges then we run again the DFS from tha same node
# and the nodes which were visited in both of the DFS are the nodes of the scc
def connected_component(self, id1: int):
if self.g is None or self.g.get_node(id1) is None:
return []
graph = GraphAlgo()
self.DFS(self.g.get_node(id1)) # first DFS
graph.g = self.reverse_graph(self.g)
graph.DFS(graph.g.get_node(id1)) # second dfs over the reverse graph
list = []
for node in graph.g.get_all_v().values():
if node.tag == 1 and self.g.get_node(node.id).tag == 1: # taking nodes wich were visited in both DFS
list.append(node.id)
return list
# simple method that reverse the graph the method copy the same nodes but copy the opposite edges
def reverse_graph(self, graph):
graph2 = DiGraph()
for node in graph.get_all_v().keys():
graph2.add_node(node)
for ver in graph.get_all_v().values():
for edge in graph.all_out_edges_of_node(ver.id).keys():
graph2.add_edge(edge, ver.id, 0)
return graph2
# The function to do DFS traversal. iterative DFS using a queue
def DFS(self, v):
for node in self.g.get_all_v().values():
node.tag = 0
q = queue.LifoQueue(maxsize=0)
v.tag = 1
q.put_nowait(v)
while not q.empty():
v = q.get()
for neighbour in self.g.all_out_edges_of_node(v.id).keys():
if self.g.get_node(neighbour).tag == 0:
self.g.get_node(neighbour).tag = 1
q.put(self.g.get_node(neighbour))
def connected_components(self):
list = []
for ver in self.g.get_all_v().values():
ver.w = -1
for vertex in self.g.get_all_v().values():
if vertex.w == 1:
continue
list2 = self.connected_component(vertex.id)
for i in list2:
self.g.get_node(i).w = 1
list.append(list2)
return list
def plot_graph(self):
x = []
y = []
n = []
max_x = -1000
min_x = 1000
max_y = -1000
min_y = 1000
for node in self.g.get_all_v().values():
n.append(node.id)
if node.pos is None:
node.pos = (int(random.randrange(0, 100, 3)), int(random.randrange(0, 100, 8)), 0)
x.append(node.pos[0])
y.append(node.pos[1])
if node.pos[0] > max_x:
max_x = node.pos[0]
if node.pos[1] > max_y:
max_y = node.pos[1]
if node.pos[0] < min_x:
min_x = node.pos[0]
if node.pos[1] < min_y:
min_y = node.pos[1]
fig, ax = plt.subplots(facecolor=(0.5, 0.8, 0.8))
ax.scatter(x, y, 100, 'red')
for ver in self.g.get_all_v().values(): # type Node
for neighbour in self.g.all_out_edges_of_node(ver.id).keys():
from_xy = (ver.pos[0], ver.pos[1])
to_xy = (self.g.get_node(neighbour).pos[0], self.g.get_node(neighbour).pos[1])
con = ConnectionPatch(from_xy, to_xy, "data", "data",
arrowstyle="-|>", shrinkA=5, shrinkB=5,
mutation_scale=18, fc="orange")
ax.add_artist(con)
for i, txt in enumerate(n):
ax.annotate(txt, (x[i], y[i] + 0.0002))
ax.text(0.5, 0.5, 'created by aviem and amiel', transform=ax.transAxes,
fontsize=30, color='gray', alpha=0.5,
ha='center', va='center', rotation='30')
plt.axis([min_x - 0.001, max_x + 0.001, min_y - 0.001, max_y + 0.001])
plt.xlabel('X axis')
plt.ylabel('Y axis')
ax.set_facecolor('#eafff5')
ax.set_title('Directed Weighted Graph')
plt.show()
def __str__(self):
print(self.g)
return ""