class TestUndirectedGraphCreation(unittest.TestCase):
def setUp(self):
self.graph = UndirectedGraph()
def test_class_init_without_data(self):
self.assertIsInstance(self.graph, UndirectedGraph)
def test_class_init_with_data_string(self):
self.G = UndirectedGraph([("a", "b"), ("b", "c")])
self.assertListEqual(sorted(self.G.nodes()), ["a", "b", "c"])
self.assertListEqual(hf.recursive_sorted(self.G.edges()), [["a", "b"], ["b", "c"]])
def test_add_node_string(self):
self.graph.add_node("a")
self.assertListEqual(self.graph.nodes(), ["a"])
def test_add_node_nonstring(self):
self.graph.add_node(1)
self.assertListEqual(self.graph.nodes(), [1])
def test_add_nodes_from_string(self):
self.graph.add_nodes_from(["a", "b", "c", "d"])
self.assertListEqual(sorted(self.graph.nodes()), ["a", "b", "c", "d"])
def test_add_nodes_from_non_string(self):
self.graph.add_nodes_from([1, 2, 3, 4])
def test_add_edge_string(self):
self.graph.add_edge("d", "e")
self.assertListEqual(sorted(self.graph.nodes()), ["d", "e"])
self.assertListEqual(hf.recursive_sorted(self.graph.edges()), [["d", "e"]])
self.graph.add_nodes_from(["a", "b", "c"])
self.graph.add_edge("a", "b")
self.assertListEqual(hf.recursive_sorted(self.graph.edges()), [["a", "b"], ["d", "e"]])
def test_add_edge_nonstring(self):
self.graph.add_edge(1, 2)
def test_add_edges_from_string(self):
self.graph.add_edges_from([("a", "b"), ("b", "c")])
self.assertListEqual(sorted(self.graph.nodes()), ["a", "b", "c"])
self.assertListEqual(hf.recursive_sorted(self.graph.edges()), [["a", "b"], ["b", "c"]])
self.graph.add_nodes_from(["d", "e", "f"])
self.graph.add_edges_from([("d", "e"), ("e", "f")])
self.assertListEqual(sorted(self.graph.nodes()), ["a", "b", "c", "d", "e", "f"])
self.assertListEqual(
hf.recursive_sorted(self.graph.edges()),
hf.recursive_sorted([("a", "b"), ("b", "c"), ("d", "e"), ("e", "f")]),
)
def test_add_edges_from_nonstring(self):
self.graph.add_edges_from([(1, 2), (2, 3)])
def test_number_of_neighbors(self):
self.graph.add_edges_from([("a", "b"), ("b", "c")])
self.assertEqual(len(self.graph.neighbors("b")), 2)
def tearDown(self):
del self.graph
def to_junction_tree(self):
"""
Creates a junction tree (or clique tree) for a given markov model.
For a given markov model (H) a junction tree (G) is a graph
1. where each node in G corresponds to a maximal clique in H
2. each sepset in G separates the variables strictly on one side of the
edge to other.
Examples
--------
>>> from pgmpy.models import MarkovModel
>>> from pgmpy.factors import Factor
>>> mm = MarkovModel()
>>> mm.add_nodes_from(['x1', 'x2', 'x3', 'x4', 'x5', 'x6', 'x7'])
>>> mm.add_edges_from([('x1', 'x3'), ('x1', 'x4'), ('x2', 'x4'),
... ('x2', 'x5'), ('x3', 'x6'), ('x4', 'x6'),
... ('x4', 'x7'), ('x5', 'x7')])
>>> phi = [Factor(edge, [2, 2], np.random.rand(4)) for edge in mm.edges()]
>>> mm.add_factors(*phi)
>>> junction_tree = mm.to_junction_tree()
"""
from pgmpy.models import JunctionTree
# Check whether the model is valid or not
self.check_model()
# Triangulate the graph to make it chordal
triangulated_graph = self.triangulate()
# Find maximal cliques in the chordal graph
cliques = list(map(tuple, nx.find_cliques(triangulated_graph)))
# If there is only 1 clique, then the junction tree formed is just a
# clique tree with that single clique as the node
if len(cliques) == 1:
clique_trees = JunctionTree()
clique_trees.add_node(cliques[0])
# Else if the number of cliques is more than 1 then create a complete
# graph with all the cliques as nodes and weight of the edges being
# the length of sepset between two cliques
elif len(cliques) >= 2:
complete_graph = UndirectedGraph()
edges = list(itertools.combinations(cliques, 2))
weights = list(map(lambda x: len(set(x[0]).intersection(set(x[1]))),
edges))
for edge, weight in zip(edges, weights):
complete_graph.add_edge(*edge, weight=-weight)
# Create clique trees by minimum (or maximum) spanning tree method
clique_trees = JunctionTree(nx.minimum_spanning_tree(complete_graph).edges())
# Check whether the factors are defined for all the random variables or not
all_vars = itertools.chain(*[factor.scope() for factor in self.factors])
if set(all_vars) != set(self.nodes()):
ValueError('Factor for all the random variables not specified')
# Dictionary stating whether the factor is used to create clique
# potential or not
# If false, then it is not used to create any clique potential
is_used = {factor: False for factor in self.factors}
for node in clique_trees.nodes():
clique_factors = []
for factor in self.factors:
# If the factor is not used in creating any clique potential as
# well as has any variable of the given clique in its scope,
# then use it in creating clique potential
if not is_used[factor] and set(factor.scope()).issubset(node):
clique_factors.append(factor)
is_used[factor] = True
# To compute clique potential, initially set it as unity factor
var_card = [self.get_cardinality()[x] for x in node]
clique_potential = Factor(node, var_card, np.ones(np.product(var_card)))
# multiply it with the factors associated with the variables present
# in the clique (or node)
clique_potential *= factor_product(*clique_factors)
clique_trees.add_factors(clique_potential)
if not all(is_used.values()):
raise ValueError('All the factors were not used to create Junction Tree.'
'Extra factors are defined.')
return clique_trees
def test_is_triangulated(self):
G = UndirectedGraph([('A', 'B'), ('A', 'C'),
('B', 'D'), ('C', 'D')])
self.assertFalse(G.is_triangulated())
G.add_edge('A', 'D')
self.assertTrue(G.is_triangulated())
class TestUndirectedGraphCreation(unittest.TestCase):
def setUp(self):
self.graph = UndirectedGraph()
def test_class_init_without_data(self):
self.assertIsInstance(self.graph, UndirectedGraph)
def test_class_init_with_data_string(self):
self.G = UndirectedGraph([('a', 'b'), ('b', 'c')])
self.assertListEqual(sorted(self.G.nodes()), ['a', 'b', 'c'])
self.assertListEqual(hf.recursive_sorted(self.G.edges()),
[['a', 'b'], ['b', 'c']])
def test_add_node_string(self):
self.graph.add_node('a')
self.assertListEqual(self.graph.nodes(), ['a'])
def test_add_node_nonstring(self):
self.graph.add_node(1)
self.assertListEqual(self.graph.nodes(), [1])
def test_add_nodes_from_string(self):
self.graph.add_nodes_from(['a', 'b', 'c', 'd'])
self.assertListEqual(sorted(self.graph.nodes()),
['a', 'b', 'c', 'd'])
def test_add_node_with_weight(self):
self.graph.add_node('a')
self.graph.add_node('weight_a', weight=0.3)
self.assertEqual(self.graph.node['weight_a']['weight'], 0.3)
self.assertEqual(self.graph.node['a']['weight'], None)
def test_add_nodes_from_with_weight(self):
self.graph.add_node(1)
self.graph.add_nodes_from(['weight_b', 'weight_c'], weights=[0.3, 0.5])
self.assertEqual(self.graph.node['weight_b']['weight'], 0.3)
self.assertEqual(self.graph.node['weight_c']['weight'], 0.5)
self.assertEqual(self.graph.node[1]['weight'], None)
def test_add_nodes_from_non_string(self):
self.graph.add_nodes_from([1, 2, 3, 4])
def test_add_edge_string(self):
self.graph.add_edge('d', 'e')
self.assertListEqual(sorted(self.graph.nodes()), ['d', 'e'])
self.assertListEqual(hf.recursive_sorted(self.graph.edges()),
[['d', 'e']])
self.graph.add_nodes_from(['a', 'b', 'c'])
self.graph.add_edge('a', 'b')
self.assertListEqual(hf.recursive_sorted(self.graph.edges()),
[['a', 'b'], ['d', 'e']])
def test_add_edge_nonstring(self):
self.graph.add_edge(1, 2)
def test_add_edges_from_string(self):
self.graph.add_edges_from([('a', 'b'), ('b', 'c')])
self.assertListEqual(sorted(self.graph.nodes()), ['a', 'b', 'c'])
self.assertListEqual(hf.recursive_sorted(self.graph.edges()),
[['a', 'b'], ['b', 'c']])
self.graph.add_nodes_from(['d', 'e', 'f'])
self.graph.add_edges_from([('d', 'e'), ('e', 'f')])
self.assertListEqual(sorted(self.graph.nodes()),
['a', 'b', 'c', 'd', 'e', 'f'])
self.assertListEqual(hf.recursive_sorted(self.graph.edges()),
hf.recursive_sorted([('a', 'b'), ('b', 'c'),
('d', 'e'), ('e', 'f')]))
def test_add_edges_from_nonstring(self):
self.graph.add_edges_from([(1, 2), (2, 3)])
def test_number_of_neighbors(self):
self.graph.add_edges_from([('a', 'b'), ('b', 'c')])
self.assertEqual(len(self.graph.neighbors('b')), 2)
def tearDown(self):
del self.graph
def to_junction_tree(self):
"""
Creates a junction tree (or clique tree) for a given markov model.
For a given markov model (H) a junction tree (G) is a graph
1. where each node in G corresponds to a maximal clique in H
2. each sepset in G separates the variables strictly on one side of the
edge to other.
Examples
--------
>>> from pgmpy.models import MarkovModel
>>> from pgmpy.factors.discrete import DiscreteFactor
>>> mm = MarkovModel()
>>> mm.add_nodes_from(['x1', 'x2', 'x3', 'x4', 'x5', 'x6', 'x7'])
>>> mm.add_edges_from([('x1', 'x3'), ('x1', 'x4'), ('x2', 'x4'),
... ('x2', 'x5'), ('x3', 'x6'), ('x4', 'x6'),
... ('x4', 'x7'), ('x5', 'x7')])
>>> phi = [DiscreteFactor(edge, [2, 2], np.random.rand(4)) for edge in mm.edges()]
>>> mm.add_factors(*phi)
>>> junction_tree = mm.to_junction_tree()
"""
from pgmpy.models import JunctionTree
# Check whether the model is valid or not
self.check_model()
# Triangulate the graph to make it chordal
triangulated_graph = self.triangulate()
# Find maximal cliques in the chordal graph
cliques = list(map(tuple, nx.find_cliques(triangulated_graph)))
# If there is only 1 clique, then the junction tree formed is just a
# clique tree with that single clique as the node
if len(cliques) == 1:
clique_trees = JunctionTree()
clique_trees.add_node(cliques[0])
# Else if the number of cliques is more than 1 then create a complete
# graph with all the cliques as nodes and weight of the edges being
# the length of sepset between two cliques
elif len(cliques) >= 2:
complete_graph = UndirectedGraph()
edges = list(itertools.combinations(cliques, 2))
weights = list(map(lambda x: len(set(x[0]).intersection(set(x[1]))),
edges))
for edge, weight in zip(edges, weights):
complete_graph.add_edge(*edge, weight=-weight)
# Create clique trees by minimum (or maximum) spanning tree method
clique_trees = JunctionTree(nx.minimum_spanning_tree(complete_graph).edges())
# Check whether the factors are defined for all the random variables or not
all_vars = itertools.chain(*[factor.scope() for factor in self.factors])
if set(all_vars) != set(self.nodes()):
ValueError('DiscreteFactor for all the random variables not specified')
# Dictionary stating whether the factor is used to create clique
# potential or not
# If false, then it is not used to create any clique potential
is_used = {factor: False for factor in self.factors}
for node in clique_trees.nodes():
clique_factors = []
for factor in self.factors:
# If the factor is not used in creating any clique potential as
# well as has any variable of the given clique in its scope,
# then use it in creating clique potential
if not is_used[factor] and set(factor.scope()).issubset(node):
clique_factors.append(factor)
is_used[factor] = True
# To compute clique potential, initially set it as unity factor
var_card = [self.get_cardinality()[x] for x in node]
clique_potential = DiscreteFactor(node, var_card, np.ones(np.product(var_card)))
# multiply it with the factors associated with the variables present
# in the clique (or node)
clique_potential *= factor_product(*clique_factors)
clique_trees.add_factors(clique_potential)
if not all(is_used.values()):
raise ValueError('All the factors were not used to create Junction Tree.'
'Extra factors are defined.')
return clique_trees
class TestUndirectedGraphCreation(unittest.TestCase):
def setUp(self):
self.graph = UndirectedGraph()
def test_class_init_without_data(self):
self.assertIsInstance(self.graph, UndirectedGraph)
def test_class_init_with_data_string(self):
self.G = UndirectedGraph([('a', 'b'), ('b', 'c')])
self.assertListEqual(sorted(self.G.nodes()), ['a', 'b', 'c'])
self.assertListEqual(hf.recursive_sorted(self.G.edges()),
[['a', 'b'], ['b', 'c']])
def test_add_node_string(self):
self.graph.add_node('a')
self.assertListEqual(self.graph.nodes(), ['a'])
def test_add_node_nonstring(self):
self.graph.add_node(1)
self.assertListEqual(self.graph.nodes(), [1])
def test_add_nodes_from_string(self):
self.graph.add_nodes_from(['a', 'b', 'c', 'd'])
self.assertListEqual(sorted(self.graph.nodes()),
['a', 'b', 'c', 'd'])
def test_add_nodes_from_non_string(self):
self.graph.add_nodes_from([1, 2, 3, 4])
def test_add_edge_string(self):
self.graph.add_edge('d', 'e')
self.assertListEqual(sorted(self.graph.nodes()), ['d', 'e'])
self.assertListEqual(hf.recursive_sorted(self.graph.edges()),
[['d', 'e']])
self.graph.add_nodes_from(['a', 'b', 'c'])
self.graph.add_edge('a', 'b')
self.assertListEqual(hf.recursive_sorted(self.graph.edges()),
[['a', 'b'], ['d', 'e']])
def test_add_edge_nonstring(self):
self.graph.add_edge(1, 2)
def test_add_edges_from_string(self):
self.graph.add_edges_from([('a', 'b'), ('b', 'c')])
self.assertListEqual(sorted(self.graph.nodes()), ['a', 'b', 'c'])
self.assertListEqual(hf.recursive_sorted(self.graph.edges()),
[['a', 'b'], ['b', 'c']])
self.graph.add_nodes_from(['d', 'e', 'f'])
self.graph.add_edges_from([('d', 'e'), ('e', 'f')])
self.assertListEqual(sorted(self.graph.nodes()),
['a', 'b', 'c', 'd', 'e', 'f'])
self.assertListEqual(hf.recursive_sorted(self.graph.edges()),
hf.recursive_sorted([('a', 'b'), ('b', 'c'),
('d', 'e'), ('e', 'f')]))
def test_add_edges_from_nonstring(self):
self.graph.add_edges_from([(1, 2), (2, 3)])
def test_number_of_neighbors(self):
self.graph.add_edges_from([('a', 'b'), ('b', 'c')])
self.assertEqual(len(self.graph.neighbors('b')), 2)
def tearDown(self):
del self.graph
class TestUndirectedGraphCreation(unittest.TestCase):
def setUp(self):
self.graph = UndirectedGraph()
def test_class_init_without_data(self):
self.assertIsInstance(self.graph, UndirectedGraph)
def test_class_init_with_data_string(self):
self.G = UndirectedGraph([("a", "b"), ("b", "c")])
self.assertListEqual(sorted(self.G.nodes()), ["a", "b", "c"])
self.assertListEqual(hf.recursive_sorted(self.G.edges()),
[["a", "b"], ["b", "c"]])
def test_add_node_string(self):
self.graph.add_node("a")
self.assertListEqual(list(self.graph.nodes()), ["a"])
def test_add_node_nonstring(self):
self.graph.add_node(1)
self.assertListEqual(list(self.graph.nodes()), [1])
def test_add_nodes_from_string(self):
self.graph.add_nodes_from(["a", "b", "c", "d"])
self.assertListEqual(sorted(self.graph.nodes()), ["a", "b", "c", "d"])
def test_add_node_with_weight(self):
self.graph.add_node("a")
self.graph.add_node("weight_a", weight=0.3)
self.assertEqual(self.graph.nodes["weight_a"]["weight"], 0.3)
self.assertEqual(self.graph.nodes["a"]["weight"], None)
def test_add_nodes_from_with_weight(self):
self.graph.add_node(1)
self.graph.add_nodes_from(["weight_b", "weight_c"], weights=[0.3, 0.5])
self.assertEqual(self.graph.nodes["weight_b"]["weight"], 0.3)
self.assertEqual(self.graph.nodes["weight_c"]["weight"], 0.5)
self.assertEqual(self.graph.nodes[1]["weight"], None)
def test_add_nodes_from_non_string(self):
self.graph.add_nodes_from([1, 2, 3, 4])
def test_add_edge_string(self):
self.graph.add_edge("d", "e")
self.assertListEqual(sorted(self.graph.nodes()), ["d", "e"])
self.assertListEqual(hf.recursive_sorted(self.graph.edges()),
[["d", "e"]])
self.graph.add_nodes_from(["a", "b", "c"])
self.graph.add_edge("a", "b")
self.assertListEqual(hf.recursive_sorted(self.graph.edges()),
[["a", "b"], ["d", "e"]])
def test_add_edge_nonstring(self):
self.graph.add_edge(1, 2)
def test_add_edges_from_string(self):
self.graph.add_edges_from([("a", "b"), ("b", "c")])
self.assertListEqual(sorted(self.graph.nodes()), ["a", "b", "c"])
self.assertListEqual(hf.recursive_sorted(self.graph.edges()),
[["a", "b"], ["b", "c"]])
self.graph.add_nodes_from(["d", "e", "f"])
self.graph.add_edges_from([("d", "e"), ("e", "f")])
self.assertListEqual(sorted(self.graph.nodes()),
["a", "b", "c", "d", "e", "f"])
self.assertListEqual(
hf.recursive_sorted(self.graph.edges()),
hf.recursive_sorted([("a", "b"), ("b", "c"), ("d", "e"),
("e", "f")]),
)
def test_add_edges_from_nonstring(self):
self.graph.add_edges_from([(1, 2), (2, 3)])
def test_number_of_neighbors(self):
self.graph.add_edges_from([("a", "b"), ("b", "c")])
self.assertEqual(len(list(self.graph.neighbors("b"))), 2)
def tearDown(self):
del self.graph
def test_is_triangulated(self):
G = UndirectedGraph([("A", "B"), ("A", "C"), ("B", "D"), ("C", "D")])
self.assertFalse(G.is_triangulated())
G.add_edge("A", "D")
self.assertTrue(G.is_triangulated())
def test_is_triangulated(self):
G = UndirectedGraph([('A', 'B'), ('A', 'C'), ('B', 'D'), ('C', 'D')])
self.assertFalse(G.is_triangulated())
G.add_edge('A', 'D')
self.assertTrue(G.is_triangulated())