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from __future__ import annotations
import numpy as np
import pytest
from scipy.optimize import NonlinearConstraint
from bayes_opt import BayesianOptimization, ConstraintModel
@pytest.fixture
def target_function():
return lambda x, y: np.cos(2 * x) * np.cos(y) + np.sin(x)
@pytest.fixture
def constraint_function():
return lambda x, y: np.cos(x) * np.cos(y) - np.sin(x) * np.sin(y)
def test_constraint_property(target_function, constraint_function):
constraint_limit_upper = 0.5
constraint = NonlinearConstraint(constraint_function, -np.inf, constraint_limit_upper)
pbounds = {"x": (0, 6), "y": (0, 6)}
optimizer = BayesianOptimization(
f=target_function, constraint=constraint, pbounds=pbounds, verbose=0, random_state=1
)
assert isinstance(optimizer.constraint, ConstraintModel)
assert isinstance(optimizer.space.constraint, ConstraintModel)
def test_single_constraint_upper(target_function, constraint_function):
constraint_limit_upper = 0.5
constraint = NonlinearConstraint(constraint_function, -np.inf, constraint_limit_upper)
pbounds = {"x": (0, 6), "y": (0, 6)}
optimizer = BayesianOptimization(
f=target_function, constraint=constraint, pbounds=pbounds, verbose=0, random_state=1
)
optimizer.maximize(init_points=2, n_iter=10)
assert constraint_function(**optimizer.max["params"]) <= constraint_limit_upper
def test_single_constraint_lower(target_function, constraint_function):
constraint_limit_lower = -0.5
constraint = NonlinearConstraint(constraint_function, constraint_limit_lower, np.inf)
pbounds = {"x": (0, 6), "y": (0, 6)}
optimizer = BayesianOptimization(
f=target_function, constraint=constraint, pbounds=pbounds, verbose=0, random_state=1
)
optimizer.maximize(init_points=2, n_iter=10)
assert constraint_function(**optimizer.max["params"]) >= constraint_limit_lower
def test_single_constraint_lower_upper(target_function, constraint_function):
constraint_limit_lower = -0.5
constraint_limit_upper = 0.5
constraint = NonlinearConstraint(constraint_function, constraint_limit_lower, constraint_limit_upper)
pbounds = {"x": (0, 6), "y": (0, 6)}
optimizer = BayesianOptimization(
f=target_function, constraint=constraint, pbounds=pbounds, verbose=0, random_state=1
)
assert optimizer.constraint.lb == constraint.lb
assert optimizer.constraint.ub == constraint.ub
optimizer.maximize(init_points=2, n_iter=10)
# Check limits
assert constraint_function(**optimizer.max["params"]) <= constraint_limit_upper
assert constraint_function(**optimizer.max["params"]) >= constraint_limit_lower
# Exclude the last sampled point, because the constraint is not fitted on that.
res = np.array(
[[r["target"], r["constraint"], r["params"]["x"], r["params"]["y"]] for r in optimizer.res[:-1]]
)
xy = res[:, [2, 3]]
x = res[:, 2]
y = res[:, 3]
# Check accuracy of approximation for sampled points
assert constraint_function(x, y) == pytest.approx(optimizer.constraint.approx(xy), rel=1e-5, abs=1e-5)
assert constraint_function(x, y) == pytest.approx(
optimizer.space.constraint_values[:-1], rel=1e-5, abs=1e-5
)
def test_multiple_constraints(target_function):
def constraint_function_2_dim(x, y):
return np.array(
[-np.cos(x) * np.cos(y) + np.sin(x) * np.sin(y), -np.cos(x) * np.cos(-y) + np.sin(x) * np.sin(-y)]
)
constraint_limit_lower = np.array([-np.inf, -np.inf])
constraint_limit_upper = np.array([0.6, 0.6])
conmod = NonlinearConstraint(constraint_function_2_dim, constraint_limit_lower, constraint_limit_upper)
pbounds = {"x": (0, 6), "y": (0, 6)}
optimizer = BayesianOptimization(
f=target_function, constraint=conmod, pbounds=pbounds, verbose=0, random_state=1
)
optimizer.maximize(init_points=2, n_iter=10)
constraint_at_max = constraint_function_2_dim(**optimizer.max["params"])
assert np.all(
(constraint_at_max <= constraint_limit_upper) & (constraint_at_max >= constraint_limit_lower)
)
params = optimizer.res[0]["params"]
x, y = params["x"], params["y"]
assert constraint_function_2_dim(x, y) == pytest.approx(
optimizer.constraint.approx(np.array([x, y])), rel=1e-3, abs=1e-3
)
def test_kwargs_not_the_same(target_function):
def target_function(x, y):
return np.cos(2 * x) * np.cos(y) + np.sin(x)
def constraint_function(a, b):
return np.cos(a) * np.cos(b) - np.sin(a) * np.sin(b)
constraint_limit_upper = 0.5
constraint = NonlinearConstraint(constraint_function, -np.inf, constraint_limit_upper)
pbounds = {"x": (0, 6), "y": (0, 6)}
optimizer = BayesianOptimization(
f=target_function, constraint=constraint, pbounds=pbounds, verbose=0, random_state=1
)
with pytest.raises(TypeError, match="Encountered TypeError when evaluating"):
optimizer.maximize(init_points=2, n_iter=10)
def test_lower_less_than_upper(target_function):
def target_function(x, y):
return np.cos(2 * x) * np.cos(y) + np.sin(x)
def constraint_function_2_dim(x, y):
return np.array(
[-np.cos(x) * np.cos(y) + np.sin(x) * np.sin(y), -np.cos(x) * np.cos(-y) + np.sin(x) * np.sin(-y)]
)
constraint_limit_lower = np.array([0.6, -np.inf])
constraint_limit_upper = np.array([0.3, 0.6])
conmod = NonlinearConstraint(constraint_function_2_dim, constraint_limit_lower, constraint_limit_upper)
pbounds = {"x": (0, 6), "y": (0, 6)}
with pytest.raises(ValueError):
BayesianOptimization(f=target_function, constraint=conmod, pbounds=pbounds, verbose=0, random_state=1)
def test_null_constraint_function():
constraint = ConstraintModel(None, np.array([0, 0]), np.array([1, 1]))
with pytest.raises(ValueError, match="No constraint function was provided."):
constraint.eval()
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