def test_remove_edge(self):
print("test_remove_edge")
graph = DiGraph()
graph.add_node(0)
graph.add_node(1)
graph.add_edge(0, 1, 1)
self.assertTrue(len(graph.get_edges()), 1)
graph.remove_edge(0, 1)
self.assertTrue(len(graph.get_edges()), 0)
def test_init_graph(self):
print("test_init_graph")
graph = DiGraph()
mc = graph.get_mc()
edges = graph.get_edges()
nodes = graph.get_nodes()
edge_size = graph.e_size()
node_size = graph.v_size()
self.assertEqual(mc, 0)
self.assertEqual(edge_size, 0)
self.assertEqual(node_size, 0)
self.assertIsInstance(edges, dict)
self.assertIsInstance(nodes, dict)
def test_get_edges(self):
print("test_get_edges")
graph = DiGraph()
graph.add_node(1)
graph.add_node(2)
graph.add_node(3)
graph.add_edge(1, 2, 1)
graph.add_edge(1, 3, 2)
graph.add_edge(3, 1, 3)
edges = graph.get_edges()
self.assertIsNotNone(edges)
self.assertIsNotNone(edges[1])
self.assertIsNotNone(edges[3])
self.assertIsNotNone(edges[1][2])
self.assertIsNotNone(edges[1][2])
self.assertIsNotNone(edges[3][1])
e1 = edges[1][2]
e2 = edges[1][3]
e3 = edges[3][1]
self.assertTrue(e1.getWeight(), 1)
self.assertTrue(e2.getWeight(), 2)
self.assertTrue(e3.getWeight(), 3)
class GraphAlgo(GraphAlgoInterface):
def __init__(self, graph=None):
if graph is None:
self.directed_weighted_graph = DiGraph()
else:
self.directed_weighted_graph = graph
self.parent = {}
self.dis = {}
def get_graph(self) -> GraphInterface:
"""
:return: the directed graph on which the algorithm works on.
"""
return self.directed_weighted_graph
def parse_file_name(self, file_name):
file_name = file_name.replace('/', '\\')
file_name = file_name.replace('\\\\', '\\')
file_name = file_name.split('\\')
base_path = Path(__file__).parent.parent
file_path = ""
for i in range(len(file_name) - 1):
if not file_name[i].startswith('..'):
file_path += file_name[i] + '/'
file_path = (base_path / file_path /
file_name[len(file_name) - 1]).resolve()
return file_path
def load_from_json(self, file_name: str) -> bool:
"""
Loads a graph from a json file.
@param file_name: The path to the json file
@returns True if the loading was successful, False o.w.
"""
file_path = self.parse_file_name(file_name)
with open(file_path, 'r') as fp:
data = json.load(fp)
nodes = data["Nodes"]
edges = data["Edges"]
for n in nodes:
if "pos" in n:
pos = n['pos']
if type(pos) == str:
pos = tuple(pos.split(','))
pos = (float(pos[0]), float(pos[1]))
self.directed_weighted_graph.add_node(n["id"], pos)
else:
self.directed_weighted_graph.add_node(n["id"])
for e in edges:
self.directed_weighted_graph.add_edge(e["src"], e["dest"], e["w"])
return True
def save_to_json(self, file_name: str) -> bool:
"""
Saves the graph in JSON format to a file
@param file_name: The path to the out file
@return: True if the save was successful, False o.w.
"""
file_name = self.parse_file_name(file_name)
try:
os.remove(file_name)
except OSError:
pass
edges = self.directed_weighted_graph.get_edges()
nodes = self.directed_weighted_graph.get_nodes()
json_file = {}
jsonEdges = []
jsonNodes = []
for src in edges:
for dest in edges[src]:
edge = edges[src][dest]
parsed_edge = {
'src': edge.getSrc(),
'dest': edge.getDest(),
'w': edge.getWeight()
}
jsonEdges.append(parsed_edge)
for k in nodes:
if nodes[k].getLocation():
pos = nodes[k].getLocation()
parsed_node = {'pos': pos, 'id': k}
else:
parsed_node = {'id': k}
jsonNodes.append(parsed_node)
json_file["Edges"] = jsonEdges
json_file["Nodes"] = jsonNodes
with open(file_name, 'x') as fp:
json.dump(json_file, fp)
return True
def shortest_path_dist(self, src: int, dest: int) -> float:
if src == dest:
return 0
self.dijkstra(self.directed_weighted_graph.getNode(src))
return self.dis[dest]
def shortest_path(self, id1: int, id2: int) -> (float, list):
"""
Returns the shortest path from node id1 to node id2 using Dijkstra's Algorithm
@param id1: The start node id
@param id2: The end node id
@return: The distance of the path, a list of the nodes ids that the path goes through
Example:
# >>> from GraphAlgo import GraphAlgo
# >>> g_algo = GraphAlgo()
# >>> g_algo.addNode(0)
# >>> g_algo.addNode(1)
# >>> g_algo.addNode(2)
# >>> g_algo.addEdge(0,1,1)
# >>> g_algo.addEdge(1,2,4)
# >>> g_algo.shortestPath(0,1)
# (1, [0, 1])
# >>> g_algo.shortestPath(0,2)
# (5, [0, 1, 2])
Notes:
If there is no path between id1 and id2, or one of them dose not exist the function returns (float('inf'),[])
More info:
https://en.wikipedia.org/wiki/Dijkstra's_algorithm
"""
if self.directed_weighted_graph.getNode(
id1) is None or self.directed_weighted_graph.getNode(
id2) is None:
return None
self.dijkstra(self.directed_weighted_graph.getNode(id1))
s = self.directed_weighted_graph.getNode(id2)
path = []
while s is not None:
path.append(s.getKey())
s = self.parent[s.getKey()]
path.reverse()
weight = self.dis[id2]
if weight == float('inf'):
return weight, []
return weight, path
"""
function Dijkstra(Graph, source):
create vertex set Q
for each vertex v in Graph: // Initialization
dist[v] ← INFINITY // Unknown distance from source to v
prev[v] ← UNDEFINED // Previous node in optimal path from source
add v to Q // All nodes initially in Q (unvisited nodes)
dist[source] ← 0 // Distance from source to source
while Q is not empty:
u ← vertex in Q with min dist[u] // Node with the least distance will be selected first
remove u from Q
for each neighbor v of u: // where v is still in Q.
alt ← dist[u] + length(u, v)
if alt < dist[v]: // A shorter path to v has been found
dist[v] ← alt
prev[v] ← u
return dist[], prev[]
"""
def dijkstra(self, src):
self.dis = {}
self.parent = {}
visited = set()
q = []
for n in self.directed_weighted_graph.get_all_v():
self.dis[n.getKey()] = float('inf')
self.parent[n.getKey()] = None
self.dis[src.getKey()] = float(0)
q.append((src.getKey(), 0))
while len(q) > 0 and len(
visited) != self.directed_weighted_graph.v_size():
key = q.pop(0)[0]
if key not in visited:
for v in self.directed_weighted_graph.getNode(
key).getOutEdges():
if v.getDest() not in visited:
if self.directed_weighted_graph.getEdge(
key, v.getDest()) is not None:
tempSum = self.dis[
key] + self.directed_weighted_graph.getEdge(
key, v.getDest()).getWeight()
if tempSum < self.dis[v.getDest()]:
self.dis[v.getDest()] = tempSum
self.parent[v.getDest(
)] = self.directed_weighted_graph.getNode(key)
q.append((v.getDest(), self.dis[v.getDest()]))
sorted(q, key=lambda n: n[1])
visited.add(key)
def connected_component(self, id1: int) -> list:
"""
Finds the Strongly Connected Component(SCC) that node id1 is a part of.
@param id1: The node id
@return: The list of nodes in the SCC
Notes:
If the graph is None or id1 is not in the graph, the function should return an empty list []
"""
list = []
if self.directed_weighted_graph.getNode(id1) is None:
return list
list.append(id1)
for n in self.directed_weighted_graph.get_all_v():
if self.shortest_path(
n.getKey(), id1)[0] != float('inf') and self.shortest_path(
id1, n.getKey())[0] != float('inf'):
if n.getKey() is not id1:
list.append(n.getKey())
return list
def connected_components(self) -> List[list]:
"""
Finds all the Strongly Connected Component(SCC) in the graph.
@return: The list all SCC
Notes:
If the graph is None the function should return an empty list []
"""
lists = []
if self.directed_weighted_graph is None:
return lists
for n in self.directed_weighted_graph.get_all_v():
lists.append(self.connected_component(n.getKey()))
return lists
def plot_graph(self) -> None:
"""
Plots the graph.
If the nodes have a position, the nodes will be placed there.
Otherwise, they will be placed in a random but elegant manner.
@return: None
"""
ax = plt.axes()
min_x = float('inf')
max_x = -float('inf')
min_y = float('inf')
max_y = -float('inf')
for node in self.directed_weighted_graph.get_nodes():
mynode = self.directed_weighted_graph.getNode(node)
node_pos = mynode.getLocation()
if node_pos is not None:
if node_pos[0] < min_x:
min_x = node_pos[0]
if node_pos[1] < min_y:
min_y = 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]
else:
min_x, max_x, min_y, max_y = 0, 500, 0, 500
plt.xlim(min_x + (min_x * 0.59), max_x + (max_x * 0.59))
plt.ylim(min_y + (min_y * 0.59), (max_y * 0.59) + max_y)
edges = self.directed_weighted_graph.get_edges()
plotted = []
circles = []
for src in edges:
src_node = self.directed_weighted_graph.getNode(src)
for dest in edges[src]:
dest_node = self.directed_weighted_graph.getNode(dest)
src_pos = src_node.getLocation()
dest_pos = dest_node.getLocation()
if src_pos is None:
src_pos = [
random.uniform(min_x, max_x),
random.uniform(min_y, max_y)
]
src_node.setLocation(src_pos[0], src_pos[1])
if dest_pos is None:
dest_pos = [
random.uniform(min_x, max_x),
random.uniform(min_y, max_y)
]
dest_node.setLocation(dest_pos[0], dest_pos[1])
c1 = plt.Circle((src_pos[0], src_pos[1]),
max_x / 100 + max_y / 100,
color='r')
c2 = plt.Circle((dest_pos[0], dest_pos[1]),
max_x / 100 + max_y / 100,
color='r')
if c1 not in circles:
circles.append(c1)
if c2 not in circles:
circles.append(c2)
if (src_pos[0] == dest_pos[0] and src_pos[1] == dest_pos[1]):
dest_pos = (dest_pos[0] + 0.1, dest_pos[1] + 0.1)
plt.arrow(src_pos[0],
src_pos[1],
dest_pos[0] - src_pos[0],
dest_pos[1] - src_pos[1],
head_width=max_x * 0.039,
length_includes_head=True,
head_length=max_y * 0.039,
width=max_y * 0.00002 * max_y,
color='black',
fc="tan")
plt.title('|V|=' + str(self.directed_weighted_graph.v_size()) +
',' + '|E|= ' +
str(self.directed_weighted_graph.e_size()) + ')',
fontdict={
'color': 'white',
'fontsize': 19,
'fontweight': 980
})
if (src_pos[0], src_pos[1]) not in plotted:
label = ax.annotate(src_node.getKey(),
xy=(src_pos[0], src_pos[1]),
fontsize=15)
plotted.append([src_pos[0], src_pos[1]])
if (dest_pos[0], dest_pos[1]) not in plotted:
label = ax.annotate(dest_node.getKey(),
xy=(dest_pos[0], dest_pos[1]),
fontsize=15)
plotted.append([dest_pos[0], dest_pos[1]])
for i in circles:
ax.add_artist(i)
plt.show()
