def __init__(self,
space,
model,
utility,
expectation_utility=None,
optimizer='lbfgs',
inner_optimizer='lbfgs',
parallel=False,
n_starting=400,
n_anchor=20,
include_baseline_points=False,
**kwargs):
self.space = space
self.model = model
self.utility = utility
self.expectation_utility = expectation_utility
self.optimizer_name = optimizer
self.inner_optimizer_name = inner_optimizer
self.parallel = parallel
self.n_starting = n_starting
self.n_anchor = n_anchor
self.include_baseline_points = include_baseline_points
self.number_of_utility_parameter_samples = 3
self.full_parameter_support = self.utility.parameter_distribution.use_full_support
self.number_of_gp_hyps_samples = min(
10, self.model.number_of_hyps_samples())
self.n_attributes = self.model.output_dim
self.kwargs = kwargs
## -- save extra options than can be passed to the optimizer
if 'model' in self.kwargs:
self.model = self.kwargs['model']
if 'anchor_points_logic' in self.kwargs:
self.type_anchor_points_logic = self.kwargs[
'type_anchor_points_logic']
else:
self.type_anchor_points_logic = max_objective_anchor_points_logic
## -- Context handler: takes
self.context_manager = ContextManager(space)
## -- Set optimizer and inner optimizer (WARNING: this won't update context)
self.optimizer = choose_optimizer(
self.optimizer_name, self.context_manager.noncontext_bounds)
self.inner_optimizer = choose_optimizer(
self.inner_optimizer_name, self.context_manager.noncontext_bounds)
def __init__(self, model, space, optimizer, utility):
super(uTS, self).__init__(model, space)
self.optimizer_name = optimizer
self.utility = utility
#
self.context_manager = ContextManager(self.space)
self.optimizer = choose_optimizer(self.optimizer_name, self.context_manager.noncontext_bounds)
self.X_aux = None
self.Y_aux = None
def optimize_inner_func(self,
f=None,
df=None,
f_df=None,
duplicate_manager=None,
n_starting=400,
n_anchor=20):
"""
Optimizes the input function.
:param f: function to optimize.
:param df: gradient of the function to optimize.
:param f_df: returns both the function to optimize and its gradient.
"""
self.f = f
self.df = df
self.f_df = f_df
# Update the optimizer, in case context has beee passed.
self.inner_optimizer = choose_optimizer(
self.inner_optimizer_name, self.context_manager.noncontext_bounds)
# Selecting the anchor points and removing duplicates
if self.type_anchor_points_logic == max_objective_anchor_points_logic:
anchor_points_generator = ObjectiveAnchorPointsGenerator(
self.space, latin_design_type, f, n_starting)
elif self.type_anchor_points_logic == thompson_sampling_anchor_points_logic:
anchor_points_generator = ThompsonSamplingAnchorPointsGenerator(
self.space, sobol_design_type, self.model)
# Select the anchor points (with context)
anchor_points, anchor_points_values = anchor_points_generator.get(
num_anchor=n_anchor,
duplicate_manager=duplicate_manager,
context_manager=self.context_manager,
get_scores=True)
# Applying local optimizers at the anchor points and update bounds of the optimizer (according to the context)
optimized_points = [
apply_optimizer_inner(self.inner_optimizer,
a,
f=f,
df=None,
f_df=f_df,
duplicate_manager=duplicate_manager,
context_manager=self.context_manager,
space=self.space) for a in anchor_points
]
x_min, fx_min = min(optimized_points, key=lambda t: t[1])
#x_min = np.atleast_2d(anchor_points[0])
#fx_min = np.atleast_2d(anchor_points_values[0])
return x_min, fx_min
def optimize(self, f=None, df=None, f_df=None, duplicate_manager=None):
"""
Optimizes the input function.
:param f: function to optimize.
:param df: gradient of the function to optimize.
:param f_df: returns both the function to optimize and its gradient.
"""
self.f = f
self.df = df
self.f_df = f_df
# Update the optimizer, in case context has beee passed.
self.optimizer = choose_optimizer(
self.optimizer_name, self.context_manager.noncontext_bounds)
# Selecting the anchor points and removing duplicates
if self.type_anchor_points_logic == max_objective_anchor_points_logic:
anchor_points_generator = ObjectiveAnchorPointsGenerator(
self.space, random_design_type, f, self.n_starting)
elif self.type_anchor_points_logic == thompson_sampling_anchor_points_logic:
anchor_points_generator = ThompsonSamplingAnchorPointsGenerator(
self.space, sobol_design_type, self.model)
# Select the anchor points (with context)
anchor_points, anchor_points_values = anchor_points_generator.get(
num_anchor=self.n_anchor,
duplicate_manager=duplicate_manager,
context_manager=self.context_manager,
get_scores=True)
# Baseline points
if self.include_baseline_points:
X_baseline = []
if self.full_parameter_support:
utility_parameter_samples = self.utility.parameter_distribution.support
else:
utility_parameter_samples = self.utility.parameter_distribution.sample(
self.number_of_utility_parameter_samples)
for i in range(len(utility_parameter_samples)):
marginal_argmax = self._current_marginal_argmax(
utility_parameter_samples[i])
X_baseline.append(marginal_argmax[0, :])
X_baseline = np.atleast_2d(X_baseline)
fX_baseline = f(X_baseline)[:, 0]
anchor_points = np.vstack((anchor_points, X_baseline))
anchor_points_values = np.concatenate(
(anchor_points_values, fX_baseline))
print('Anchor points:')
print(anchor_points)
print('Anchor points values:')
print(anchor_points_values)
if self.parallel:
pool = Pool(4)
optimized_points = pool.map(self._parallel_optimization_wrapper,
anchor_points)
print('optimized points (parallel):')
else:
optimized_points = [
apply_optimizer(self.optimizer,
a,
f=f,
df=None,
f_df=f_df,
duplicate_manager=duplicate_manager,
context_manager=self.context_manager,
space=self.space) for a in anchor_points
]
print('Optimized points (sequential):')
print(optimized_points)
x_min, fx_min = min(optimized_points, key=lambda t: t[1])
fx_min = np.squeeze(fx_min)
if self.include_baseline_points:
fx_min_baseline = fX_baseline.min()
if fx_min_baseline < fx_min:
print('Baseline point was best found.')
optimal_indices = np.atleast_1d(np.argmin(fX_baseline))
index = random.choice(optimal_indices)
x_min = np.atleast_2d(X_baseline[index, :])
fx_min = fX_baseline[index]
elif fx_min_baseline == fx_min:
print('Baseline point is a good as best optimized point.')
use_baseline_point = np.random.binomial(1, 0.5, 1)
if use_baseline_point:
print('Baseline point will be used.')
optimal_indices = np.atleast_1d(np.argmin(fX_baseline))
index = random.choice(optimal_indices)
x_min = np.atleast_2d(X_baseline[index, :])
fx_min = fX_baseline[index]
print('Acquisition value of selected point: {}'.format(fx_min))
return x_min, fx_min
