From 1e40981b27f6c8a3384d19cb0a8a338d5063a70c Mon Sep 17 00:00:00 2001
From: Rogier van der Geer <rogiervandergeer@godatadriven.com>
Date: Fri, 15 May 2020 17:08:19 +0200
Subject: [PATCH] Change the signature of pick_random
Parent pickers are no longer passed any kwargs. The pick_random must
now be initialised before use, the number of parents passed to it
upon initialization. In addition, pickers must always return a sequence
of picked parents - even if it is only one.
These changes make it much easier to implement more complex picking
algorithms, and in addition they remove the requirement for the
select_arguments() decorator, which hurts my eyes.
---
evol/helpers/pickers.py | 19 ++++++++++++-------
evol/population.py | 6 +++---
evol/utils.py | 11 ++++-------
examples/number_of_parents.py | 4 ++--
examples/population_demo.py | 2 +-
examples/rock_paper_scissors.py | 2 +-
examples/travelling_salesman.py | 2 +-
tests/conftest.py | 2 +-
tests/test_evolution.py | 2 +-
tests/test_logging.py | 20 ++++++++------------
tests/test_population.py | 13 ++++++-------
tests/test_utils.py | 12 ++++++------
12 files changed, 46 insertions(+), 49 deletions(-)
diff --git a/evol/helpers/pickers.py b/evol/helpers/pickers.py
index 14bce74..53ef20a 100644
--- a/evol/helpers/pickers.py
+++ b/evol/helpers/pickers.py
@@ -1,14 +1,19 @@
-from typing import Sequence, Tuple
-
from random import choice
+from typing import Callable, Sequence, Tuple
from evol import Individual
-def pick_random(parents: Sequence[Individual], n_parents: int = 2) -> Tuple:
- """Randomly selects parents with replacement
+def pick_random(n_parents: int = 2) -> Callable[[Sequence[Individual]], Tuple[Individual, ...]]:
+ """Returns a parent-picker that randomly samples parents with replacement.
+
+ Typical usage:
+ Evolution().breed(parent_picker=pick_random(n_parents=2), combiner=some_combiner)
- Accepted arguments:
- n_parents: Number of parents to select. Defaults to 2.
+ :param n_parents: The number of parents the picker should return.
+ :return: Callable
"""
- return tuple(choice(parents) for _ in range(n_parents))
+ def picker(parents: Sequence[Individual]) -> Tuple[Individual, ...]:
+ return tuple(choice(parents) for _ in range(n_parents))
+
+ return picker
diff --git a/evol/population.py b/evol/population.py
index cf81419..b7f2784 100644
--- a/evol/population.py
+++ b/evol/population.py
@@ -18,8 +18,8 @@
from evol.conditions import Condition
from evol.exceptions import StopEvolution
from evol.helpers.groups import group_random
-from evol.utils import offspring_generator, select_arguments
from evol.serialization import SimpleSerializer
+from evol.utils import offspring_generator, select_arguments
if TYPE_CHECKING:
from .evolution import Evolution
@@ -160,7 +160,7 @@ def evaluate(self, lazy: bool = False) -> 'BasePopulation':
pass
def breed(self,
- parent_picker: Callable[..., Sequence[Individual]],
+ parent_picker: Callable[[Sequence[Individual]], Sequence[Individual]],
combiner: Callable,
population_size: Optional[int] = None,
**kwargs) -> 'BasePopulation':
@@ -182,7 +182,7 @@ def breed(self,
if population_size:
self.intended_size = population_size
offspring = offspring_generator(parents=self.individuals,
- parent_picker=select_arguments(parent_picker),
+ parent_picker=parent_picker,
combiner=select_arguments(combiner),
**kwargs)
self.individuals += list(islice(offspring, self.intended_size - len(self.individuals)))
diff --git a/evol/utils.py b/evol/utils.py
index 08d8759..1d4fd8a 100644
--- a/evol/utils.py
+++ b/evol/utils.py
@@ -1,11 +1,11 @@
from inspect import signature
-from typing import List, Callable, Union, Sequence, Any, Generator
+from typing import List, Callable, Sequence, Any, Generator
from evol import Individual
def offspring_generator(parents: List[Individual],
- parent_picker: Callable[..., Union[Individual, Sequence]],
+ parent_picker: Callable[[Sequence[Individual]], Sequence[Individual]],
combiner: Callable[..., Any],
**kwargs) -> Generator[Individual, None, None]:
"""Generator for offspring.
@@ -25,11 +25,8 @@ def offspring_generator(parents: List[Individual],
"""
while True:
# Obtain parent chromosomes
- selected_parents = parent_picker(parents, **kwargs)
- if isinstance(selected_parents, Individual):
- chromosomes = (selected_parents.chromosome,)
- else:
- chromosomes = tuple(individual.chromosome for individual in selected_parents)
+ selected_parents = parent_picker(parents)
+ chromosomes = tuple(individual.chromosome for individual in selected_parents)
# Create children
combined = combiner(*chromosomes, **kwargs)
if isinstance(combined, Generator):
diff --git a/examples/number_of_parents.py b/examples/number_of_parents.py
index 1ad6ab4..18f930e 100644
--- a/examples/number_of_parents.py
+++ b/examples/number_of_parents.py
@@ -22,7 +22,7 @@ def init_func():
def eval_func(x, opt_value=opt_value):
return -((x - opt_value) ** 2) + math.cos(x - opt_value)
- def random_parent_picker(pop, n_parents):
+ def random_parent_picker(pop):
return [random.choice(pop) for i in range(n_parents)]
def mean_parents(*parents):
@@ -36,7 +36,7 @@ def add_noise(chromosome, sigma):
evo = (Evolution()
.survive(fraction=survival)
- .breed(parent_picker=random_parent_picker, combiner=mean_parents, n_parents=n_parents)
+ .breed(parent_picker=random_parent_picker, combiner=mean_parents)
.mutate(mutate_function=add_noise, sigma=noise)
.evaluate())
diff --git a/examples/population_demo.py b/examples/population_demo.py
index 8cb2466..20839be 100644
--- a/examples/population_demo.py
+++ b/examples/population_demo.py
@@ -11,7 +11,7 @@ def func_to_optimise(x):
def pick_random_parents(pop):
- return random.choice(pop)
+ return random.choice(pop),
random.seed(42)
diff --git a/examples/rock_paper_scissors.py b/examples/rock_paper_scissors.py
index 2a98dda..0bf6dfb 100755
--- a/examples/rock_paper_scissors.py
+++ b/examples/rock_paper_scissors.py
@@ -120,7 +120,7 @@ def run_rock_paper_scissors(population_size: int = 100,
evo = Evolution().repeat(
evolution=(Evolution()
.survive(fraction=survive_fraction)
- .breed(parent_picker=pick_random, combiner=lambda x, y: x.combine(y), n_parents=2)
+ .breed(parent_picker=pick_random(n_parents=2), combiner=lambda x, y: x.combine(y))
.mutate(lambda x: x.mutate())
.evaluate()
.callback(history.log)),
diff --git a/examples/travelling_salesman.py b/examples/travelling_salesman.py
index 213b305..bb00254 100755
--- a/examples/travelling_salesman.py
+++ b/examples/travelling_salesman.py
@@ -47,7 +47,7 @@ def print_function(population: Population):
island_evo = (Evolution()
.survive(fraction=0.5)
- .breed(parent_picker=pick_random, combiner=cycle_crossover)
+ .breed(parent_picker=pick_random(n_parents=2), combiner=cycle_crossover)
.mutate(swap_elements))
evo = (Evolution()
diff --git a/tests/conftest.py b/tests/conftest.py
index e2e70f3..665b1f8 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -54,7 +54,7 @@ def simple_evolution():
return (
Evolution()
.survive(fraction=0.5)
- .breed(parent_picker=pick_random, n_parents=2, combiner=lambda x, y: x + y)
+ .breed(parent_picker=pick_random(n_parents=2), combiner=lambda x, y: x + y)
.mutate(lambda x: x + 1, probability=0.1)
)
diff --git a/tests/test_evolution.py b/tests/test_evolution.py
index 9c53633..c030522 100644
--- a/tests/test_evolution.py
+++ b/tests/test_evolution.py
@@ -41,7 +41,7 @@ def callback(pop):
sub_evo = (
Evolution()
.survive(fraction=0.5)
- .breed(parent_picker=pick_random,
+ .breed(parent_picker=pick_random(n_parents=2),
combiner=lambda x, y: x + y)
.callback(callback_function=callback)
)
diff --git a/tests/test_logging.py b/tests/test_logging.py
index 4749e85..a71f5ae 100644
--- a/tests/test_logging.py
+++ b/tests/test_logging.py
@@ -56,9 +56,8 @@ def test_baselogger_works_via_evolution_callback(self, tmpdir, capsys):
pop = Population(chromosomes=range(10), eval_function=lambda x: x)
evo = (Evolution()
.survive(fraction=0.5)
- .breed(parent_picker=pick_random,
- combiner=lambda mom, dad: (mom + dad) / 2 + (random.random() - 0.5),
- n_parents=2)
+ .breed(parent_picker=pick_random(n_parents=2),
+ combiner=lambda mom, dad: (mom + dad) / 2 + (random.random() - 0.5))
.callback(logger.log, foo='bar'))
pop.evolve(evolution=evo, n=2)
# check characteristics of the file
@@ -132,9 +131,8 @@ def test_summarylogger_works_via_evolution(self, tmpdir, capsys):
pop = Population(chromosomes=list(range(10)), eval_function=lambda x: x)
evo = (Evolution()
.survive(fraction=0.5)
- .breed(parent_picker=pick_random,
- combiner=lambda mom, dad: (mom + dad) / 2 + (random.random() - 0.5),
- n_parents=2)
+ .breed(parent_picker=pick_random(n_parents=2),
+ combiner=lambda mom, dad: (mom + dad) / 2 + (random.random() - 0.5))
.evaluate()
.callback(logger.log, foo='bar'))
pop.evolve(evolution=evo, n=5)
@@ -157,9 +155,8 @@ def test_two_populations_can_use_same_logger(self, tmpdir, capsys):
pop2 = Population(chromosomes=list(range(10)), eval_function=lambda x: x)
evo = (Evolution()
.survive(fraction=0.5)
- .breed(parent_picker=pick_random,
- combiner=lambda mom, dad: (mom + dad) + 1,
- n_parents=2)
+ .breed(parent_picker=pick_random(n_parents=2),
+ combiner=lambda mom, dad: (mom + dad) + 1)
.evaluate()
.callback(logger.log, foo="dino"))
pop1.evolve(evolution=evo, n=5)
@@ -183,9 +180,8 @@ def test_every_mechanic_in_evolution_log(self, tmpdir, capsys):
pop = Population(chromosomes=list(range(10)), eval_function=lambda x: x)
evo = (Evolution()
.survive(fraction=0.5)
- .breed(parent_picker=pick_random,
- combiner=lambda mom, dad: (mom + dad) + 1,
- n_parents=2)
+ .breed(parent_picker=pick_random(n_parents=2),
+ combiner=lambda mom, dad: (mom + dad) + 1)
.evaluate()
.callback(logger.log, every=2))
pop.evolve(evolution=evo, n=100)
diff --git a/tests/test_population.py b/tests/test_population.py
index 636ecdc..fe457d2 100644
--- a/tests/test_population.py
+++ b/tests/test_population.py
@@ -172,14 +172,13 @@ def test_breed_amount_works(self, simple_chromosomes, simple_evaluation_function
def test_breed_works_with_kwargs(self, simple_chromosomes, simple_evaluation_function):
pop1 = Population(chromosomes=simple_chromosomes, eval_function=simple_evaluation_function)
- pop1.survive(n=50).breed(parent_picker=pick_random,
- combiner=lambda mom, dad: (mom + dad) / 2,
- n_parents=2)
+ pop1.survive(n=50).breed(parent_picker=pick_random(),
+ combiner=lambda mom, dad: (mom + dad) / 2)
assert len(pop1) == len(simple_chromosomes)
pop2 = Population(chromosomes=simple_chromosomes, eval_function=simple_evaluation_function)
- pop2.survive(n=50).breed(parent_picker=pick_random,
+ pop2.survive(n=50).breed(parent_picker=pick_random(n_parents=3),
combiner=lambda *parents: sum(parents)/len(parents),
- population_size=400, n_parents=3)
+ population_size=400)
assert len(pop2) == 400
assert pop2.intended_size == 400
@@ -187,13 +186,13 @@ def test_breed_raises_with_multiple_values_for_kwarg(self, simple_population):
(simple_population
.survive(fraction=0.5)
- .breed(parent_picker=pick_random,
+ .breed(parent_picker=pick_random(n_parents=2),
combiner=lambda x, y: x + y))
with raises(TypeError):
(simple_population
.survive(fraction=0.5)
- .breed(parent_picker=pick_random,
+ .breed(parent_picker=pick_random(n_parents=2),
combiner=lambda x, y: x + y, y=2))
diff --git a/tests/test_utils.py b/tests/test_utils.py
index d98f659..0d2ccce 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -12,18 +12,18 @@ def combiner(x, y):
return 1
result = offspring_generator(parents=simple_population.individuals,
- parent_picker=pick_random, combiner=combiner)
+ parent_picker=pick_random(), combiner=combiner)
assert isinstance(next(result), Individual)
assert next(result).chromosome == 1
@mark.parametrize('n_parents', [1, 2, 3, 4])
def test_args(self, n_parents: int, simple_population: Population):
- def combiner(*parents, n_parents):
+ def combiner(*parents):
assert len(parents) == n_parents
return 1
- result = offspring_generator(parents=simple_population.individuals, n_parents=n_parents,
- parent_picker=pick_random, combiner=combiner)
+ result = offspring_generator(parents=simple_population.individuals,
+ parent_picker=pick_random(n_parents=n_parents), combiner=combiner)
assert isinstance(next(result), Individual)
assert next(result).chromosome == 1
@@ -32,7 +32,7 @@ def combiner(x):
return 1
def picker(parents):
- return parents[0]
+ return parents[0],
result = offspring_generator(parents=simple_population.individuals, parent_picker=picker, combiner=combiner)
assert isinstance(next(result), Individual)
@@ -44,7 +44,7 @@ def combiner(x, y):
yield 2
result = offspring_generator(parents=simple_population.individuals,
- parent_picker=pick_random, combiner=combiner)
+ parent_picker=pick_random(), combiner=combiner)
for _ in range(10):
assert next(result).chromosome == 1
assert next(result).chromosome == 2