def mutate_gene(self, genome, p_add, p_delete):
"""
Mutate only a single gene.
"""
if p_add < 0 or p_delete < 0:
raise Exception("Mutation parameters must not be negative.")
if p_add + p_delete > 1:
raise Exception("Sum of the mutation probabilities must be less than 1.")
mutated_individual = BehaviorTreeStringRepresentation([])
max_attempts = 100
attempts = 0
while (not mutated_individual.is_valid() or mutated_individual.bt == genome) and attempts < max_attempts:
mutated_individual.set(genome)
index = random.randint(0, len(genome) - 1)
mutation = random.random()
if mutation < p_delete:
mutated_individual.delete_node(index)
elif mutation < p_delete + p_add:
mutated_individual.add_node(index)
else:
mutated_individual.change_node(index)
mutated_individual.close()
mutated_individual.trim()
attempts += 1
if attempts >= max_attempts and (not mutated_individual.is_valid() or mutated_individual.bt == genome):
mutated_individual = BehaviorTreeStringRepresentation([])
return mutated_individual.bt
def test_trim(self):
""" Tests trim function """
btsr = BehaviorTreeStringRepresentation([])
btsr.set(
['s(', 'a0', 'f(', 'a0', 'a0', ')', 'a0', 's(', 'a0', ')', ')'])
btsr.trim()
self.assertEqual(btsr.bt,
['s(', 'a0', 'f(', 'a0', 'a0', ')', 'a0', 'a0', ')'])
btsr.set(['s(', 'a0', 'f(', ')', 'a0', 's(', 'a0', ')', ')'])
btsr.trim()
self.assertEqual(btsr.bt, ['s(', 'a0', 'a0', 'a0', ')'])
btsr.set(
['s(', 'a0', 'f(', 'a1', 's(', 'a2', ')', 'a3', ')', 'a4', ')'])
btsr.trim()
self.assertEqual(btsr.bt,
['s(', 'a0', 'f(', 'a1', 'a2', 'a3', ')', 'a4', ')'])
btsr.set(['s(', 'a0', 'f(', 's(', 'a2', 'a3', ')', ')', 'a4', ')'])
btsr.trim()
self.assertEqual(btsr.bt, ['s(', 'a0', 'a2', 'a3', 'a4', ')'])
btsr.set(['s(', 'a0', ')'])
btsr.trim()
self.assertEqual(btsr.bt, ['s(', 'a0', ')'])