eckity.creators.gp_creators.tree_creator

 1from eckity.creators.creator import Creator
 2from eckity.fitness.simple_fitness import SimpleFitness
 3from eckity.genetic_encodings.gp.tree.functions import f_add, f_sub, f_mul, f_div
 4from eckity.fitness.gp_fitness import GPFitness
 5from eckity.genetic_encodings.gp.tree.tree_individual import Tree
 6
 7from abc import abstractmethod
 8
 9
10class GPTreeCreator(Creator):
11	def __init__(self,
12				 init_depth=None,
13				 function_set=None,
14				 terminal_set=None,
15				 erc_range=None,
16				 fitness_type=SimpleFitness,
17				 bloat_weight=0.1,
18				 events=None):
19		if events is None:
20			events = ["after_creation"]
21		super().__init__(events, fitness_type)
22
23		if init_depth is None:
24			init_depth = (2, 4)
25
26		if function_set is None:
27			function_set = [f_add, f_sub, f_mul, f_div]
28
29		if terminal_set is None:
30			terminal_set = ['x', 'y', 'z', 0, 1, -1]
31
32		self.init_depth = init_depth
33		self.function_set = function_set
34		self.terminal_set = terminal_set
35		self.erc_range = erc_range
36		self.bloat_weight = bloat_weight
37
38	def create_individuals(self, n_individuals, higher_is_better):
39		individuals = [Tree(function_set=self.function_set,
40							terminal_set=self.terminal_set,
41							erc_range=self.erc_range,
42							fitness=GPFitness(bloat_weight=self.bloat_weight, higher_is_better=higher_is_better),
43							init_depth=self.init_depth)
44					   for _ in range(n_individuals)]
45		for ind in individuals:
46			self.create_tree(ind, self.init_depth[1])
47		self.created_individuals = individuals
48
49		# TODO do we need this event? creator is instance of Operator and already has before/after operator
50		# self.publish("after_creation")
51
52		return individuals
53
54	@abstractmethod
55	def create_tree(self, tree_ind, max_depth):
56		pass