def test_root(self):
domain = ['a', 'b', 'c']
x1 = Variable('x1', domain)
x2 = Variable('x2', domain)
x3 = Variable('x3', domain)
variables = [x1, x2, x3]
r1 = NAryFunctionRelation(lambda x, y: x + y, [x1, x2], name='r1')
r2 = NAryFunctionRelation(lambda x, y: x - y, [x2, x3], name='r2')
relations = [r1, r2]
tree_root = _generate_dfs_tree(variables, relations, x1)
self.assertEqual(tree_root.variable, x1)
tree_root = _generate_dfs_tree(variables, relations)
self.assertIn(tree_root.variable, variables)
def test_2nodes_tree(self):
domain = ['a', 'b', 'c']
x1 = Variable('x1', domain)
x2 = Variable('x2', domain)
variables = [x1, x2]
r1 = NAryFunctionRelation(lambda x, y: x + y, [x1, x2], name='r1')
relations = [r1]
root = _generate_dfs_tree(variables, relations, root=x1)
self.assertEqual(root.variable, x1)
self.assertEqual(root.parent, None)
self.assertEqual(len(root.children), 1)
self.assertEqual(len(root.relations), 1)
node = root.children[0]
self.assertEqual(node.variable, x2)
self.assertEqual(root.pseudo_children, [])
self.assertEqual(root.pseudo_parents, [])
self.assertEqual(node.parent, root)
self.assertEqual(node.children, [])
self.assertEqual(node.pseudo_children, [])
self.assertEqual(node.pseudo_parents, [])
self.assertEqual(node.relations, [r1])
check_tree(root)
def test_4nodes(self):
# Graph with 4 nodes, one cycle
#
# x1---X3
# \ /
# x2---x4
domain = ['a', 'b', 'c']
x1 = Variable('x1', domain)
x2 = Variable('x2', domain)
x3 = Variable('x3', domain)
x4 = Variable('x4', domain)
variables = [x1, x2, x3, x4]
def binary_func(x, y):
return x + y
r1 = NAryFunctionRelation(binary_func, [x1, x2], name='r1')
r2 = NAryFunctionRelation(binary_func, [x1, x3], name='r2')
r3 = NAryFunctionRelation(binary_func, [x2, x3], name='r3')
r4 = NAryFunctionRelation(binary_func, [x2, x4], name='r4')
relations = [r1, r2, r3, r4]
root = _generate_dfs_tree(variables, relations, root=x1)
_filter_relation_to_lowest_node(root)
check_tree(root)
self.assertEqual(root.variable, x1)
self.assertEqual(root.parent, None)
self.assertEqual(len(root.children), 1)
self.assertEqual(len(root.relations), 0)
def test_3nodes_tree_cycle_3ary_rel_bottom(self):
# A graph with 3 variables and a single 3-ary relation.
domain = ['a', 'b', 'c']
x1 = Variable('x1', domain)
x2 = Variable('x2', domain)
x3 = Variable('x3', domain)
variables = [x1, x2, x3]
r1 = NAryFunctionRelation(lambda x, y, z: x + y + z, [x1, x2, x3],
name='r1')
relations = [r1]
root = _generate_dfs_tree(variables, relations, root=x1)
_filter_relation_to_lowest_node(root)
self.assertEqual(root.variable, x1)
self.assertEqual(root.parent, None)
self.assertEqual(len(root.children), 1)
self.assertEqual(len(root.relations), 0)
c1 = root.children[0]
self.assertIn(c1.variable, [x2, x3])
self.assertEqual(len(root.pseudo_children), 1)
self.assertEqual(root.pseudo_parents, [])
self.assertEqual(c1.parent, root)
self.assertEqual(len(c1.children), 1)
c2 = c1.children[0]
self.assertEqual(c2.children, [])
self.assertEqual(c2.pseudo_children, [])
self.assertEqual(c2.pseudo_parents, [root])
self.assertEqual(len(c1.relations) + len(c2.relations), 1)
check_tree(root)
def test_3nodes_tree_cycle(self):
domain = ['a', 'b', 'c']
x1 = Variable('x1', domain)
x2 = Variable('x2', domain)
x3 = Variable('x3', domain)
variables = [x1, x2, x3]
r1 = NAryFunctionRelation(lambda x, y: x + y, [x1, x2], name='r1')
r2 = NAryFunctionRelation(lambda x, y: x + y, [x1, x3], name='r2')
r3 = NAryFunctionRelation(lambda x, y: x + y, [x2, x3], name='r3')
relations = [r1, r2, r3]
dcop = DCOP('test', 'min')
dcop.add_constraint(r1)
dcop.add_constraint(r2)
dcop.add_constraint(r3)
cg = build_computation_graph(dcop)
self.assertEqual(len(cg.nodes), len(variables))
self.assertEqual(len(cg.roots), 1)
# All variables have the same number of neighbors, they could all be
# root
self.assertIn(cg.roots[0].variable, [x1, x2, x3])
self.assertEqual(cg.roots[0].parent, None)
root = _generate_dfs_tree(variables, relations, root=x1)
self.assertEqual(root.variable, x1)
self.assertEqual(root.parent, None)
def test_3nodes_tree_cycle(self):
domain = ['a', 'b', 'c']
x1 = Variable('x1', domain)
x2 = Variable('x2', domain)
x3 = Variable('x3', domain)
variables = [x1, x2, x3]
r1 = NAryFunctionRelation(lambda x, y: x + y, [x1, x2], name='r1')
r2 = NAryFunctionRelation(lambda x, y: x + y, [x1, x3], name='r2')
r3 = NAryFunctionRelation(lambda x, y: x + y, [x2, x3], name='r3')
relations = [r1, r2, r3]
root = _generate_dfs_tree(variables, relations, root=x1)
self.assertEqual(root.variable, x1)
self.assertEqual(root.parent, None)
self.assertEqual(len(root.children), 1)
c1 = root.children[0]
self.assertIn(c1.variable, [x2, x3])
self.assertEqual(len(root.pseudo_children), 1)
self.assertEqual(root.pseudo_parents, [])
self.assertEqual(c1.parent, root)
self.assertEqual(len(c1.children), 1)
c2 = c1.children[0]
self.assertEqual(c2.children, [])
self.assertEqual(c2.pseudo_children, [])
self.assertEqual(c2.pseudo_parents, [root])
check_tree(root)
def test_visit_tree(self):
domain = ['a', 'b', 'c']
x1 = Variable('x1', domain)
x2 = Variable('x2', domain)
x3 = Variable('x3', domain)
x4 = Variable('x4', domain)
variables = [x1, x2, x3, x4]
binary_func = lambda x, y: x + y
r1 = NAryFunctionRelation(binary_func, [x1, x2], name='r1')
r2 = NAryFunctionRelation(binary_func, [x1, x3], name='r2')
r3 = NAryFunctionRelation(binary_func, [x2, x3], name='r3')
r4 = NAryFunctionRelation(binary_func, [x2, x4], name='r4')
relations = [r1, r2, r3, r4]
root = _generate_dfs_tree(variables, relations, root=x1)
for node in _visit_tree(root):
self.assertIn(node.variable, variables)
variables.remove(node.variable)
self.assertEqual(len(variables), 0)