class SymbolDigraph:
def __init__(self, file_name, seperator):
# First pass reading the file
self._hash_table = LPHashTable(
) # This hash table is used to convert from key to vertex index
self._graph = None # The actual underlying directed graph
file = open(file_name, "r")
count = 0
lines = file.read().splitlines()
for line in lines:
data = line.split(seperator)
# Continuously adding keys to the hash table along with the corresponding index
for key in data:
if not self._hash_table.contains(key):
self._hash_table.put(key, count)
count += 1
self._keys = np.empty(
count, dtype=object) # This array to convert index to key
for name in self._hash_table.keys():
self._keys[self._hash_table.get(name)] = name
file.close()
# Second pass, Build the actual graph after knowing exactly how many vertices we will need
second_pass = open(file_name)
self._graph = DirectedGraph(count)
lines = second_pass.read().splitlines()
for line in lines:
data = line.split(seperator)
start = self._hash_table.get(data[0])
for i in range(1, len(data)):
self._graph.add_edge(start, self._hash_table.get(data[i]))
second_pass.close()
# Returns the actual graph
def graph(self):
return self._graph
# Checks if the graph contains the given key
def contains(self, key):
return self._hash_table.contains(key)
# Returns the index of the given key
def index_of(self, key):
return self._hash_table.get(key)
# Returns the key associated with the given index
def name_of(self, index):
return self._keys[index]
class TestKnots(unittest.TestCase):
def setUp(self):
self.v = Vertex('v')
self.w = Vertex('w')
self.x = Vertex('x')
self.e1 = Arc(self.v, self.w)
self.e2 = Arc(self.w, self.x)
self.e3 = Arc(self.x, self.v)
self.dg = DirectedGraph([self.v, self.w, self.x],
[self.e1, self.e2, self.e3])
def test_positive(self):
#triangular knot
self.assertEqual(self.dg.has_knot(), True)
#triangular knot w/ an edge into it
self.a = Vertex('a')
self.dg.add_vertex(self.a)
self.Kanye = Arc(self.a,self.v)
self.dg.add_edge(self.Kanye)
self.assertTrue(self.dg.has_knot())
def test_ngon_with_chord(self):
v1 = Vertex('v1')
v2 = Vertex('v2')
v3 = Vertex('v3')
v4 = Vertex('v4')
v5 = Vertex('v5')
e1 = Arc(v2,v1)
e2 = Arc(v3,v2)
e3 = Arc(v3,v4)
e4 = Arc(v4,v5)
e5 = Arc(v5,v1)
ngon = DirectedGraph([v1,v2,v3,v4,v5],
[e1,e2,e3,e4,e5])
self.assertFalse(ngon.has_knot())
chord = Arc(v1,v4)
ngon.add_edge(chord)
self.assertTrue(ngon.has_knot())
def test_ngon_with_chord(self):
v1 = Vertex('v1')
v2 = Vertex('v2')
v3 = Vertex('v3')
v4 = Vertex('v4')
v5 = Vertex('v5')
e1 = Arc(v2,v1)
e2 = Arc(v3,v2)
e3 = Arc(v3,v4)
e4 = Arc(v4,v5)
e5 = Arc(v5,v1)
ngon = DirectedGraph([v1,v2,v3,v4,v5],
[e1,e2,e3,e4,e5])
self.assertFalse(ngon.has_knot())
chord = Arc(v1,v4)
ngon.add_edge(chord)
self.assertTrue(ngon.has_knot())
self.visited = [False] * len(graph)
transpose_graph = [None] * len(graph)
for vertex in range(len(graph)):
if not self.visited[vertex]:
self.transpose_util(vertex, transpose_graph)
return transpose_graph
@staticmethod
def display_graph(graph):
for v in range(len(graph)):
print(v, " --> ", end=" ")
if graph[v] is not None:
for adj_v in graph[v]:
print(adj_v, end=" ")
print()
g = DirectedGraph(6)
g.add_edge(5, 2)
g.add_edge(5, 0)
g.add_edge(4, 0)
g.add_edge(4, 1)
g.add_edge(2, 3)
g.add_edge(3, 1)
TransposeGraph().display_graph(g.get_graph())
print("Transposed ---> ")
obj = TransposeGraph()
trans = obj.transpose(g.get_graph())
obj.display_graph(trans)
while queue:
v = queue.pop(0)
if graph[v]:
for adj_v in graph[v]:
if color[adj_v] == color[v]:
return False
if color[adj_v] is None:
queue.append(adj_v)
color[
adj_v] = "red" if color[v] == "black" else "black"
return True
g = DirectedGraph(6)
g.add_edge(0, 2)
g.add_edge(2, 0)
g.add_edge(1, 2)
g.add_edge(0, 3)
g.add_edge(0, 4)
g.add_edge(0, 5)
g.add_edge(4, 5)
# g.add_edge(2, 3)
obj = BipartiteGraph()
# print(obj.is_bipartite(g.get_graph(), 0))
lst = [[2, 4], [2, 3, 4], [0, 1], [1], [0, 1], [7],
[9], [5], [], [6], [12, 14], [], [10], [], [10], [19], [18], [], [16],
[15], [23], [23], [], [20, 21], [], [], [27], [26], [], [], [34],
[33, 34], [], [31], [30, 31], [38, 39], [37, 38, 39], [36], [35, 36],
[35, 36], [43], [], [], [40], [], [49], [47, 48, 49], [46, 48, 49],