def test_update_with_new_lower_bound(self):
tree = BabTree(MockNodeStorage(create_problem()),
KSectionBranchingStrategy(), MockSelectionStrategy())
sol = create_solution(5.0, 10.0)
tree.update_root(sol)
root_children, _ = tree.branch_at_node(tree.root)
a, b = root_children
tree.update_node(a, create_solution(7.0, 11.0))
tree.branch_at_node(a)
assert np.isclose(5.0, tree.lower_bound)
assert np.isclose(10.0, tree.upper_bound)
tree.update_node(b, create_solution(6.0, 10.0))
children, _ = tree.branch_at_node(b)
assert np.isclose(6.0, tree.lower_bound)
assert np.isclose(10.0, tree.upper_bound)
a, b = children
tree.update_node(a, create_solution(7.0, 10.0))
tree.branch_at_node(a)
assert np.isclose(6.0, tree.lower_bound)
assert np.isclose(10.0, tree.upper_bound)
def test_update_root(self):
tree = BabTree(MockNodeStorage(create_problem()),
KSectionBranchingStrategy(), MockSelectionStrategy())
sol = create_solution(5.0, 10.0)
tree.update_root(sol)
assert np.isclose(5.0, tree.lower_bound)
assert np.isclose(10.0, tree.upper_bound)
def tree():
"""Create a BaBTree like:
0
+----+----+
| | |
1 2 3
+-+-+
| |
4 5
with coordinates:
0 : [0]
1 : [0, 0]
2 : [0, 1]
3 : [0, 2]
4 : [0, 2, 0]
5 : [0, 2, 1]
"""
problem = create_problem()
storage = MockNodeStorage(problem)
t = BabTree(storage, KSectionBranchingStrategy(), MockSelectionStrategy())
t.update_root(create_solution(-30.0, 0.0))
root = t.root
bp = BranchingPoint(problem.variable(0), [0.0, 0.5])
root.branch_at_point(bp)
c = root.children[2]
bp = BranchingPoint(problem.variable(1), [0.0])
c.branch_at_point(bp)
return t
def test_branch_on_list_of_points(self, problem):
tree = MockTree()
node = Node(MockNodeStorage(problem), tree, coordinate=[0])
node.update(create_solution(0.0, 1.0))
new_nodes, _ = node.branch(MockBranching([-0.5, 0.0, 0.5, 1.0, 1.5]))
assert len(new_nodes) == 6
expected_bounds = [(-1, -0.5), (-0.5, 0.0), (0.0, 0.5), (0.5, 1.0),
(1.0, 1.5), (1.5, 2.0)]
self._assert_bounds_are_correct(new_nodes, expected_bounds)
def test_ksection(self, problem, solution):
ksection_strat = KSectionBranchingStrategy(7)
tree = BabTree(
MockNodeStorage(problem),
ksection_strat,
FakeSelectionStrategy(),
)
node = tree.root
for i in range(5):
node.update(create_solution(0.0, 1.0))
children, _ = node.branch(ksection_strat)
assert len(children) == 7
for child in children:
assert child.variable.idx == i
node = children[0]
def solution():
return create_solution(0.0, 1.0)
def solution():
return create_solution(-20.0, -10.0)