def test_base_branch(self):
node = BaseNode(small_branch.lp, small_branch.integerIndices,
-float('inf'))
node.bound()
idx = 2
rtn = node._base_branch(2)
# check each node
for name, n in rtn.items():
self.assertTrue(
all(n._lp.matrix.elements == node._lp.matrix.elements))
self.assertTrue(all(n._lp.objective == node._lp.objective))
self.assertTrue(
all(n._lp.constraintsLower == node._lp.constraintsLower))
self.assertTrue(
all(n._lp.constraintsUpper == node._lp.constraintsUpper))
if name == 'down':
self.assertTrue(all(n._lp.variablesUpper >= [1e10, 1e10, 1]))
self.assertTrue(n._lp.variablesUpper[idx] == 1)
self.assertTrue(
all(n._lp.variablesLower == node._lp.variablesLower))
else:
self.assertTrue(
all(n._lp.variablesUpper == node._lp.variablesUpper))
self.assertTrue(all(n._lp.variablesLower == [0, 0, 2]))
# check basis statuses work - i.e. are warm started
for i in [0, 1]:
self.assertTrue(
all(node._lp.getBasisStatus()[i] == n._lp.getBasisStatus()
[i]), 'bases should match')
def test_base_branch(self):
node = BaseNode(small_branch.lp, small_branch.integerIndices)
node.bound()
idx = 2
out = {next_node_idx: node._base_branch(2, next_node_idx) for
next_node_idx in [None, 1]}
# confirm current node is no longer a leaf
self.assertFalse(node.is_leaf)
# check each node
for next_node_idx, rtn in out.items():
for name, n in rtn.items():
if name not in ['left', 'right']:
continue
self.assertTrue(all(n.lp.matrix.elements == node.lp.matrix.elements))
self.assertTrue(all(n.lp.objective == node.lp.objective))
self.assertTrue(all(n.lp.constraintsLower == node.lp.constraintsLower))
self.assertTrue(all(n.lp.constraintsUpper == node.lp.constraintsUpper))
self.assertTrue(n._integer_indices == node._integer_indices)
self.assertTrue(n.lower_bound == node.objective_value)
self.assertTrue(n._b_idx == idx)
self.assertTrue(n._b_val == 1.5)
self.assertTrue(n.depth == 1)
if name == 'left':
self.assertTrue(all(n.lp.variablesUpper == [10, 10, 1]))
self.assertTrue(n.lp.variablesUpper[idx] == 1)
self.assertTrue(all(n.lp.variablesLower == node.lp.variablesLower))
self.assertTrue(n.lineage == (1, ) if next_node_idx else n.lineage is None)
self.assertTrue(n.idx == 1 if next_node_idx else n.idx is None)
self.assertTrue(n._b_dir == 'left')
else:
self.assertTrue(all(n.lp.variablesUpper == node.lp.variablesUpper))
self.assertTrue(all(n.lp.variablesLower == [0, 0, 2]))
self.assertTrue(n.lineage == (2,) if next_node_idx else n.lineage is None)
self.assertTrue(n.idx == 2 if next_node_idx else n.idx is None)
self.assertTrue(n._b_dir == 'right')
# check basis statuses work - i.e. are warm started
for i in [0, 1]:
self.assertTrue(all(node.lp.getBasisStatus()[i] ==
n.lp.getBasisStatus()[i]), 'bases should match')
# check other returns
self.assertTrue(rtn['next_node_idx'] == 3 if next_node_idx else
rtn['next_node_idx'] is None)
def test_strong_branch(self):
iters = 5
node = BaseNode(random.lp, random.integerIndices, 0)
node.bound()
idx = node._most_fractional_index
# test we stay within iters and improve bound/stay same
rtn = node._strong_branch(idx, iterations=iters)
for direction, child_node in rtn.items():
self.assertTrue(child_node.lp.iteration <= iters)
if child_node.lp.getStatusCode() in [0, 3]:
self.assertTrue(child_node.lp.objectiveValue >= node.objective_value)
# test call base_branch
node = BaseNode(random.lp, random.integerIndices)
node.bound()
idx = node._most_fractional_index
children = node._base_branch(idx)
with patch.object(node, '_base_branch') as bb:
bb.return_value = children
rtn = node._strong_branch(idx, iterations=iters)
self.assertTrue(bb.called)