def __init__(self, env,
greed, step_size, discount_rate, q_x_seed, q_y_seed,
gamma_optimistic, gamma_hard, lambda_hard, gamma_soft, s_x_seed, s_y_seed,
q_gp_params=None, s_gp_params=None, keep_seed_in_data=True):
"""
Initializer
:param env: the environment
:param greed: the epsilon parameter of the ConstrainedEpsilonGreedy policy
:param q_step_size: the step size in the Q-Learning update
:param discount_rate: the discount rate
:param q_x_seed: the seed input of the GP for the Q-Values model
:param q_y_seed: the seed output of the GP for the Q-Values model
:param gamma_optimistic: the gamma parameter for Q_optimistic
:param gamma_hard: the gamma parameter for Q_hard, the set where Q-Learning is constrained (~ Q_cautious)
:param lambda_hard: the lambda parameter for Q_hard AND Q_soft
:param gamma_soft: the gamma parameter for Q_soft, the set outside of which the safety measure is updated
:param s_x_seed: the seed input of the GP for the safety model
:param s_y_seed: the seed output of the GP for the safety model
:param q_gp_params: the parameters defining the GP for the Q-Values model. See edge.models.inference.MaternGP
for more information
:param q_gp_params: the parameters defining the GP for the safety model. See edge.models.inference.MaternGP
for more information
:param keep_seed_in_data: whether to keep the seed data in the GPs datasets. Should be True, otherwise GPyTorch
fails.
"""
Q_model = GPQLearning(env.stateaction_space, step_size, discount_rate,
x_seed=q_x_seed, y_seed=q_y_seed,
gp_params=q_gp_params)
safety_model = MaternSafety(env.stateaction_space, gamma_optimistic,
x_seed=s_x_seed, y_seed=s_y_seed,
gp_params=s_gp_params)
super(SoftHardLearner, self).__init__(env, Q_model, safety_model)
self.Q_model = Q_model
self.safety_model = safety_model
self.lambda_hard = lambda_hard
self.gamma_hard = gamma_hard
self.gamma_soft = gamma_soft
self._gamma_optimistic = gamma_optimistic
self.constrained_value_policy = ConstrainedEpsilonGreedy(
self.env.stateaction_space, greed)
self.safety_maximization_policy = SafetyMaximization(
self.env.stateaction_space)
self.active_sampling_policy = SafetyActiveSampling(
self.env.stateaction_space)
self.keep_seed_in_data = keep_seed_in_data
if not keep_seed_in_data:
self.Q_model.empty_data()
self.violated_soft_constraint = None
self.updated_safety = None
def __init__(self, env, s_gp_params, gamma_cautious, lambda_cautious,
gamma_optimistic, base_controller):
super().__init__(env, s_gp_params, gamma_cautious, lambda_cautious,
gamma_optimistic, checks_safety=True,
learn_safety=True, is_free_from_safety=False,
always_update_safety=True, safety_model=None)
self.policy = base_controller
self.active_sampling_policy = SafetyActiveSampling(
self.env.stateaction_space
)
self.safety_maximization_policy = SafetyMaximization(
self.env.stateaction_space
)
def __init__(self,
env,
safety_measure,
greed,
step_size,
discount_rate,
safety_threshold,
x_seed,
y_seed,
gp_params=None,
keep_seed_in_data=True):
"""
Initializer
:param env: the environment
:param safety_measure: either SafetyTruth or SafetyModel of the environment
:param greed: the epsilon parameter of the ConstrainedEpsilonGreedy policy
:param step_size: the step size in the Q-Learning update
:param discount_rate: the discount rate
:param safety_threshold: the lambda threshold used to evaluate safety. This is 0 theoretically, but an Agent
that is at the exact boundary of the viability kernel still fails due to rounding errors. Hence, this should
be a small, positive value.
:param x_seed: the seed input of the GP
:param y_seed: the seed output of the GP
:param gp_params: the parameters defining the GP. See edge.models.inference.MaternGP for more information
:param keep_seed_in_data: whether to keep the seed data in the GP dataset. Should be True, otherwise GPyTorch
fails.
"""
Q_model = GPQLearning(env.stateaction_space,
step_size,
discount_rate,
x_seed=x_seed,
y_seed=y_seed,
gp_params=gp_params)
super(ConstrainedQLearner, self).__init__(env, Q_model)
self.Q_model = Q_model
self.safety_measure = safety_measure
self.constrained_value_policy = ConstrainedEpsilonGreedy(
self.env.stateaction_space, greed)
self.safety_maximization_policy = SafetyMaximization(
self.safety_measure.stateaction_space)
self.safety_threshold = safety_threshold
self.keep_seed_in_data = keep_seed_in_data
if not keep_seed_in_data:
self.Q_model.empty_data()
def __init__(self, env, s_gp_params, gamma_cautious, lambda_cautious,
gamma_optimistic, checks_safety=True, learn_safety=True,
is_free_from_safety=False, always_update_safety=False,
safety_model=None,
*models):
self.gamma_cautious_s, self.gamma_cautious_e = gamma_cautious
self.lambda_cautious_s, self.lambda_cautious_e = lambda_cautious
self.gamma_optimistic_s, self.gamma_optimistic_e = gamma_optimistic
self.gamma_cautious = self.gamma_cautious_s
self.lambda_cautious = self.lambda_cautious_s
if safety_model is not None:
self.safety_model = safety_model
else:
x_seed = s_gp_params.pop('train_x')
y_seed = s_gp_params.pop('train_y')
self.safety_model = MaternSafety(
env,
gamma_measure=self.gamma_optimistic_s,
x_seed=x_seed,
y_seed=y_seed,
gp_params=s_gp_params
)
super().__init__(env, self.safety_model, *models)
self.safety_learning_policy = SafetyInformationMaximization(
env.stateaction_space
)
self.safe_projection_policy = SafeProjectionPolicy(
env.stateaction_space
)
self.safety_maximization_policy = SafetyMaximization(
self.env.stateaction_space
)
self.active_sampling_policy = SafetyActiveSampling(
self.env.stateaction_space
)
self.last_controller_action = None
self.safety_update = None
self.checks_safety = checks_safety
self.followed_controller = None
self.always_update_safety = always_update_safety
self.violated_constraint = None
self.is_free_from_safety = is_free_from_safety
self.learn_safety = learn_safety
class ConstrainedQLearner(Agent):
"""
Defines an Agent modelling the Q-Values with a MaternGP updated with the Q-Learning update. The Agent also has a
model for the underlying safety measure, either via a SafetyTruth or a SafetyModel, but this model is then
not updated. The Agent then acts with a ConstrainedEpsilonGreedy policy, staying in the safe set.
"""
def __init__(self,
env,
safety_measure,
greed,
step_size,
discount_rate,
safety_threshold,
x_seed,
y_seed,
gp_params=None,
keep_seed_in_data=True):
"""
Initializer
:param env: the environment
:param safety_measure: either SafetyTruth or SafetyModel of the environment
:param greed: the epsilon parameter of the ConstrainedEpsilonGreedy policy
:param step_size: the step size in the Q-Learning update
:param discount_rate: the discount rate
:param safety_threshold: the lambda threshold used to evaluate safety. This is 0 theoretically, but an Agent
that is at the exact boundary of the viability kernel still fails due to rounding errors. Hence, this should
be a small, positive value.
:param x_seed: the seed input of the GP
:param y_seed: the seed output of the GP
:param gp_params: the parameters defining the GP. See edge.models.inference.MaternGP for more information
:param keep_seed_in_data: whether to keep the seed data in the GP dataset. Should be True, otherwise GPyTorch
fails.
"""
Q_model = GPQLearning(env.stateaction_space,
step_size,
discount_rate,
x_seed=x_seed,
y_seed=y_seed,
gp_params=gp_params)
super(ConstrainedQLearner, self).__init__(env, Q_model)
self.Q_model = Q_model
self.safety_measure = safety_measure
self.constrained_value_policy = ConstrainedEpsilonGreedy(
self.env.stateaction_space, greed)
self.safety_maximization_policy = SafetyMaximization(
self.safety_measure.stateaction_space)
self.safety_threshold = safety_threshold
self.keep_seed_in_data = keep_seed_in_data
if not keep_seed_in_data:
self.Q_model.empty_data()
@property
def greed(self):
"""
Returns the epsilon parameter of the ConstrainedEpsilonGreedy policy
:return: epsilon parameter
"""
return self.constrained_value_policy.greed
@greed.setter
def greed(self, new_greed):
"""
Sets the epsilon parameter of the ConstrainedEpsilonGreedy policy
"""
self.constrained_value_policy.greed = new_greed
def get_next_action(self):
all_actions = self.Q_model.space.action_space[:].reshape(-1, 1)
action_is_viable = np.array([
self.safety_measure.measure(self.state, a) > self.safety_threshold
for a in all_actions
])
q_values = self.Q_model[self.state, :]
action = self.constrained_value_policy.get_action(
q_values, action_is_viable)
if action is None:
print('No viable action, taking the safest...')
safety_values = self.safety_measure.measure(
self.state, slice(None, None, None))
action = self.safety_maximization_policy.get_action(safety_values)
if action is None:
raise NoActionError('The agent could not find a suitable action')
return action
def get_random_safe_state(self):
"""
Returns a random state that is classified as safe by the safety model
:return: a safe state
"""
is_viable = self.safety_measure.state_measure > 0
viable_indexes = np.argwhere(is_viable).squeeze()
state_index = viable_indexes[np.random.choice(len(viable_indexes))]
state = self.safety_measure.stateaction_space.state_space[state_index]
return state
def update_models(self, state, action, next_state, reward, failed):
self.Q_model.update(state, action, next_state, reward, failed)
def fit_models(self, train_x, train_y, epochs, **optimizer_kwargs):
self.Q_model.fit(train_x, train_y, epochs, **optimizer_kwargs)
if not self.keep_seed_in_data:
self.Q_model.empty_data()
def __init__(self,
env,
greed,
step_size,
discount_rate,
q_x_seed,
q_y_seed,
gamma_optimistic,
gamma_cautious,
lambda_cautious,
s_x_seed,
s_y_seed,
q_gp_params=None,
s_gp_params=None,
keep_seed_in_data=True):
"""
Initializer
:param env: the environment
:param greed: the epsilon parameter of the ConstrainedEpsilonGreedy
policy
:param step_size: the step size in the Q-Learning update
:param discount_rate: the discount rate
:param q_x_seed: the seed input of the GP for the Q-Values model
:param q_y_seed: the seed output of the GP for the Q-Values model
:param gamma_optimistic: the gamma parameter for Q_optimistic
:param gamma_cautious: the gamma parameter for Q_cautious
:param lambda_cautious: the lambda parameter for Q_cautious
:param s_x_seed: the seed input of the GP for the safety model
:param s_y_seed: the seed output of the GP for the safety model
:param q_gp_params: the parameters defining the GP for the Q-Values
model. See edge.models.inference.MaternGP
for more information
:param q_gp_params: the parameters defining the GP for the safety model.
See edge.models.inference.MaternGP for more information
:param keep_seed_in_data: whether to keep the seed data in the GPs
datasets. Should be True, otherwise GPyTorch fails.
"""
self.lambda_cautious_start, self.lambda_cautious_end = lambda_cautious
self.gamma_cautious_start, self.gamma_cautious_end = gamma_cautious
self.gamma_optimistic_start, self.gamma_optimistic_end = \
gamma_optimistic
self.lambda_cautious = self.lambda_cautious_start
self.gamma_cautious = self.gamma_cautious_start
self._step_size_decrease_index = 1
Q_model = GPQLearning(env.stateaction_space,
step_size,
discount_rate,
x_seed=q_x_seed,
y_seed=q_y_seed,
gp_params=q_gp_params)
safety_model = MaternSafety(env.stateaction_space,
self.gamma_optimistic_start,
x_seed=s_x_seed,
y_seed=s_y_seed,
gp_params=s_gp_params)
super(ValuesAndSafetyCombinator, self).__init__(
env=env,
greed=greed, # Unused: we define another policy
step_size=step_size,
discount_rate=discount_rate,
x_seed=q_x_seed,
y_seed=q_y_seed,
gp_params=q_gp_params,
keep_seed_in_data=keep_seed_in_data)
self.Q_model = Q_model
self.safety_model = safety_model
self.constrained_value_policy = ConstrainedEpsilonGreedy(
self.env.stateaction_space, greed)
self.safety_maximization_policy = SafetyMaximization(
self.env.stateaction_space)
self._training_greed = self.greed
self.keep_seed_in_data = keep_seed_in_data
if not keep_seed_in_data:
self.Q_model.empty_data()
class ControlledSafetyLearner(Agent):
def __init__(self, env, s_gp_params, gamma_cautious, lambda_cautious,
gamma_optimistic, checks_safety=True, learn_safety=True,
is_free_from_safety=False, always_update_safety=False,
safety_model=None,
*models):
self.gamma_cautious_s, self.gamma_cautious_e = gamma_cautious
self.lambda_cautious_s, self.lambda_cautious_e = lambda_cautious
self.gamma_optimistic_s, self.gamma_optimistic_e = gamma_optimistic
self.gamma_cautious = self.gamma_cautious_s
self.lambda_cautious = self.lambda_cautious_s
if safety_model is not None:
self.safety_model = safety_model
else:
x_seed = s_gp_params.pop('train_x')
y_seed = s_gp_params.pop('train_y')
self.safety_model = MaternSafety(
env,
gamma_measure=self.gamma_optimistic_s,
x_seed=x_seed,
y_seed=y_seed,
gp_params=s_gp_params
)
super().__init__(env, self.safety_model, *models)
self.safety_learning_policy = SafetyInformationMaximization(
env.stateaction_space
)
self.safe_projection_policy = SafeProjectionPolicy(
env.stateaction_space
)
self.safety_maximization_policy = SafetyMaximization(
self.env.stateaction_space
)
self.active_sampling_policy = SafetyActiveSampling(
self.env.stateaction_space
)
self.last_controller_action = None
self.safety_update = None
self.checks_safety = checks_safety
self.followed_controller = None
self.always_update_safety = always_update_safety
self.violated_constraint = None
self.is_free_from_safety = is_free_from_safety
self.learn_safety = learn_safety
def get_controller_action(self, *args, **kwargs):
raise NotImplementedError
@property
def gamma_optimistic(self):
return self.safety_model.gamma_measure
@gamma_optimistic.setter
def gamma_optimistic(self, new_gamma_optimistic):
self.safety_model.gamma_measure = new_gamma_optimistic
@property
def do_safety_update(self):
return self.learn_safety and ( True
# self.always_update_safety
# or self.violated_constraint
# or (not self.followed_controller)
# or self.failed
)
def update_safety_params(self, t):
self.gamma_cautious = affine_interpolation(t, self.gamma_cautious_s,
self.gamma_cautious_e)
self.lambda_cautious = affine_interpolation(t, self.lambda_cautious_s,
self.lambda_cautious_e)
self.gamma_optimistic = affine_interpolation(t, self.gamma_optimistic_s,
self.gamma_optimistic_e)
def __get_projection_with_thresholds(self, lambda_t, gamma_t,
original_action):
constraints = self.safety_model.level_set(
self.state,
lambda_threshold=lambda_t,
gamma_threshold=gamma_t
)
projected_action = self.safe_projection_policy.get_action(
to_project=original_action,
constraints=constraints
)
return projected_action
def __get_alternative_with_thresholds(self, lambda_t, gamma_t,
maximize_safety_proba=False,
use_covar_slice=False):
alt_set, safety_proba, covar_slice, covar_matrix = \
self.safety_model.level_set(
self.state,
lambda_threshold=lambda_t,
gamma_threshold=gamma_t,
return_proba=True,
return_covar=True,
return_covar_matrix=True,
)
if not maximize_safety_proba:
alt_set = alt_set.squeeze()
if alt_set.any():
ctrlr_idx = self.env.action_space.get_index_of(
self.last_controller_action, around_ok=True
)
if use_covar_slice:
alternative = self.active_sampling_policy(
covar_slice.squeeze(), alt_set
)
else:
alternative = self.safety_learning_policy.get_action(
covar_matrix[ctrlr_idx, :].squeeze(), alt_set
)
return alternative
else:
return None
else:
safety_proba = safety_proba.squeeze()
return self.safety_maximization_policy.get_action(safety_proba)
def get_next_action(self):
self.followed_controller = True
self.violated_constraint = False
self.last_controller_action = self.get_controller_action()
action = self.last_controller_action
if self.checks_safety:
controller_is_cautious = self.safety_model.is_in_level_set(
self.state, action, self.lambda_cautious, self.gamma_cautious
)
if not controller_is_cautious:
if self.is_free_from_safety:
self.violated_constraint = True
else:
# alternative = self.__get_alternative_with_thresholds(
# self.lambda_cautious, self.gamma_cautious,
# use_covar_slice=False
# )
alternative = self.__get_projection_with_thresholds(
self.lambda_cautious, self.gamma_cautious, action
)
if alternative is not None:
# We found a cautious alternative
self.violated_constraint = False
self.followed_controller = False
action = alternative
else:
self.violated_constraint = True
self.followed_controller = False
# alternative = self.__get_alternative_with_thresholds(
# 0., self.gamma_optimistic
# )
alternative = self.__get_projection_with_thresholds(
0., self.gamma_optimistic, action
)
if alternative is not None:
# We found an optimistic alternative
action = alternative
else:
# No cautious or optimistic action available:
# maximize safety probability
action = self.__get_alternative_with_thresholds(
0., self.gamma_optimistic,
maximize_safety_proba=True
)
return action
def update_models(self, state, action, next_state, reward, failed, done):
return self.safety_model.update(state, action, next_state, reward,
failed, done)
def step(self):
"""
Chooses an action according to the policy, takes a step in the Environment, and updates the models. The action
taken is available in self.last_action.
:return: new_state, reward, failed
"""
old_state = self.state
self.last_action = self.get_next_action()
self.state, reward, failed = self.env.step(self.last_action)
done = self.env.done
if self.training_mode and self.do_safety_update:
self.safety_update = self.update_models(
old_state, self.last_action, self.state, reward, failed,
done
)
else:
self.safety_update = None
return self.state, reward, failed, done
class CoRLSafetyLearner(ControlledSafetyLearner):
def __init__(self, env, s_gp_params, gamma_cautious, lambda_cautious,
gamma_optimistic, base_controller):
super().__init__(env, s_gp_params, gamma_cautious, lambda_cautious,
gamma_optimistic, checks_safety=True,
learn_safety=True, is_free_from_safety=False,
always_update_safety=True, safety_model=None)
self.policy = base_controller
self.active_sampling_policy = SafetyActiveSampling(
self.env.stateaction_space
)
self.safety_maximization_policy = SafetyMaximization(
self.env.stateaction_space
)
def get_controller_action(self, *args, **kwargs):
return self.policy(self.state)
def __get_active_sampling_with_thresholds(self, lambda_t, gamma_t,
maximize_safety_proba=False):
in_set, proba_slice, covar_slice = self.safety_model.level_set(
self.state,
lambda_threshold=lambda_t,
gamma_threshold=gamma_t,
return_proba=True,
return_covar=True
)
if not maximize_safety_proba:
in_set = in_set.squeeze()
covar_slice = covar_slice.squeeze()
action = self.active_sampling_policy.get_action(
covar_slice, in_set
)
return action
else:
proba_slice = proba_slice.squeeze()
return self.safety_maximization_policy.get_action(proba_slice)
def get_next_action(self):
if self.training_mode:
self.last_controller_action = self.get_controller_action()
self.followed_controller = False
self.violated_constraint = False
action = self.__get_active_sampling_with_thresholds(
self.lambda_cautious, self.gamma_cautious
)
if action is not None:
self.violated_constraint = False
else:
self.violated_constraint = True
action = self.__get_active_sampling_with_thresholds(
0., self.gamma_optimistic
)
if action is None:
action = self.__get_active_sampling_with_thresholds(
0., self.gamma_optimistic, maximize_safety_proba=True
)
return action
else:
return super().get_next_action()
class EpsCorlLearner(Agent):
"""
Defines an Agent modelling the Q-Values with a MaternGP updated with the Q-Learning update. The Agent also has a
model for the underlying safety measure with a SafetyModel, and the Q-Learning update is constrained to stay in the
current estimate of the safe set. The exploration is either the Q-Learning update is taken, or the safety measure
update is.
"""
def __init__(self,
env,
greed,
step_size,
discount_rate,
q_x_seed,
q_y_seed,
gamma_optimistic,
gamma_cautious,
lambda_cautious,
s_x_seed,
s_y_seed,
q_gp_params=None,
s_gp_params=None,
keep_seed_in_data=True):
"""
Initializer
:param env: the environment
:param greed: the epsilon parameter of the ConstrainedEpsilonGreedy policy
:param q_step_size: the step size in the Q-Learning update
:param discount_rate: the discount rate
:param q_x_seed: the seed input of the GP for the Q-Values model
:param q_y_seed: the seed output of the GP for the Q-Values model
:param gamma_optimistic: the gamma parameter for Q_optimistic
:param gamma_cautious: the gamma parameter for Q_cautious
:param lambda_cautious: the lambda parameter for Q_cautious
:param s_x_seed: the seed input of the GP for the safety model
:param s_y_seed: the seed output of the GP for the safety model
:param q_gp_params: the parameters defining the GP for the Q-Values model. See edge.models.inference.MaternGP
for more information
:param q_gp_params: the parameters defining the GP for the safety model. See edge.models.inference.MaternGP
for more information
:param keep_seed_in_data: whether to keep the seed data in the GPs datasets. Should be True, otherwise GPyTorch
fails.
"""
Q_model = GPQLearning(env.stateaction_space,
step_size,
discount_rate,
x_seed=q_x_seed,
y_seed=q_y_seed,
gp_params=q_gp_params)
safety_model = MaternSafety(env.stateaction_space,
gamma_optimistic,
x_seed=s_x_seed,
y_seed=s_y_seed,
gp_params=s_gp_params)
super(EpsCorlLearner, self).__init__(env, Q_model, safety_model)
self.Q_model = Q_model
self.safety_model = safety_model
self.lambda_cautious = lambda_cautious
self.gamma_cautious = gamma_cautious
self._gamma_optimistic = gamma_optimistic
self.constrained_value_policy = ConstrainedEpsilonGreedy(
self.env.stateaction_space, 0)
self.safety_maximization_policy = SafetyMaximization(
self.env.stateaction_space)
self.active_sampling_policy = SafetyActiveSampling(
self.env.stateaction_space)
self.keep_seed_in_data = keep_seed_in_data
if not keep_seed_in_data:
self.Q_model.empty_data()
self.has_explored = None
self._greed = greed
@property
def greed(self):
"""
Returns the epsilon parameter balancing the exploration/exploitation
:return: epsilon parameter
"""
return self._greed
@greed.setter
def greed(self, new_greed):
"""
Sets the epsilon parameter balancing the exploration/exploitation
"""
self._greed = new_greed
@property
def gamma_optimistic(self):
return self._gamma_optimistic
@gamma_optimistic.setter
def gamma_optimistic(self, new_gamma_optimistic):
self._gamma_optimistic = new_gamma_optimistic
self.safety_model.gamma_measure = new_gamma_optimistic
def get_next_action(self):
self.has_explored = np.random.binomial(n=1, p=self.greed) == 1
is_cautious, proba_slice, covar_slice = self.safety_model.level_set(
self.state,
lambda_threshold=self.lambda_cautious,
gamma_threshold=self.gamma_cautious,
return_proba=True,
return_covar=True)
is_cautious = is_cautious.squeeze()
proba_slice = proba_slice.squeeze()
covar_slice = covar_slice.squeeze()
if self.has_explored:
action = self.active_sampling_policy.get_action(
covar_slice, is_cautious)
else:
q_values = self.Q_model[self.state, :]
action = self.constrained_value_policy.get_action(
q_values, is_cautious)
if action is None:
print('No viable action, taking the safest...')
action = self.safety_maximization_policy.get_action(proba_slice)
return action
def get_random_safe_state(self):
"""
Returns a random state that is classified as safe by the safety model
:return: a safe state
"""
is_viable = self.safety_model.measure(
slice(None, None, None),
lambda_threshold=self.lambda_cautious,
gamma_threshold=self.gamma_cautious) > 0
viable_indexes = np.atleast_1d(np.argwhere(is_viable).squeeze())
try:
state_index = viable_indexes[np.random.choice(len(viable_indexes))]
except Exception as e:
print('ERROR:', str(e))
return None
state = self.env.stateaction_space.state_space[state_index]
return state
def update_models(self, state, action, next_state, reward, failed):
self.Q_model.update(state, action, next_state, reward, failed)
self.safety_model.update(state, action, next_state, reward, failed)
def fit_models(self,
q_train_x=None,
q_train_y=None,
q_epochs=None,
q_optimizer_kwargs=None,
s_train_x=None,
s_train_y=None,
s_epochs=None,
s_optimizer_kwargs=None):
if q_train_x is not None:
if q_optimizer_kwargs is None:
q_optimizer_kwargs = {}
self.Q_model.fit(q_train_x, q_train_y, q_epochs,
**q_optimizer_kwargs)
if not self.keep_seed_in_data:
self.Q_model.empty_data()
if s_train_x is not None:
if s_optimizer_kwargs is None:
s_optimizer_kwargs = {}
self.safety_model.fit(s_train_x, s_train_y, s_epochs,
**s_optimizer_kwargs)
if not self.keep_seed_in_data:
self.safety_model.empty_data()
def step(self):
"""
Chooses an action according to the policy, takes a step in the Environment, and updates the models. The action
taken is available in self.last_action.
:return: new_state, reward, failed
"""
old_state = self.state
action = self.get_next_action()
new_state, reward, failed = self.env.step(action)
if self.has_explored or failed:
self.safety_model.update(old_state, action, new_state, reward,
failed)
else:
self.update_models(old_state, action, new_state, reward, failed)
self.state = new_state
self.last_action = action
return new_state, reward, failed
class SoftHardLearner(Agent):
"""
Defines an Agent modelling the Q-Values with a MaternGP updated with the Q-Learning update. The Agent also has a
model for the underlying safety measure with a SafetyModel, and the Q-Learning update is constrained to stay in the
current estimate of the safe set. If the update chosen by Q-Learning is within a conservative estimate of the
viable set, then the sample is used to update the safety model.
"""
def __init__(self, env,
greed, step_size, discount_rate, q_x_seed, q_y_seed,
gamma_optimistic, gamma_hard, lambda_hard, gamma_soft, s_x_seed, s_y_seed,
q_gp_params=None, s_gp_params=None, keep_seed_in_data=True):
"""
Initializer
:param env: the environment
:param greed: the epsilon parameter of the ConstrainedEpsilonGreedy policy
:param q_step_size: the step size in the Q-Learning update
:param discount_rate: the discount rate
:param q_x_seed: the seed input of the GP for the Q-Values model
:param q_y_seed: the seed output of the GP for the Q-Values model
:param gamma_optimistic: the gamma parameter for Q_optimistic
:param gamma_hard: the gamma parameter for Q_hard, the set where Q-Learning is constrained (~ Q_cautious)
:param lambda_hard: the lambda parameter for Q_hard AND Q_soft
:param gamma_soft: the gamma parameter for Q_soft, the set outside of which the safety measure is updated
:param s_x_seed: the seed input of the GP for the safety model
:param s_y_seed: the seed output of the GP for the safety model
:param q_gp_params: the parameters defining the GP for the Q-Values model. See edge.models.inference.MaternGP
for more information
:param q_gp_params: the parameters defining the GP for the safety model. See edge.models.inference.MaternGP
for more information
:param keep_seed_in_data: whether to keep the seed data in the GPs datasets. Should be True, otherwise GPyTorch
fails.
"""
Q_model = GPQLearning(env.stateaction_space, step_size, discount_rate,
x_seed=q_x_seed, y_seed=q_y_seed,
gp_params=q_gp_params)
safety_model = MaternSafety(env.stateaction_space, gamma_optimistic,
x_seed=s_x_seed, y_seed=s_y_seed,
gp_params=s_gp_params)
super(SoftHardLearner, self).__init__(env, Q_model, safety_model)
self.Q_model = Q_model
self.safety_model = safety_model
self.lambda_hard = lambda_hard
self.gamma_hard = gamma_hard
self.gamma_soft = gamma_soft
self._gamma_optimistic = gamma_optimistic
self.constrained_value_policy = ConstrainedEpsilonGreedy(
self.env.stateaction_space, greed)
self.safety_maximization_policy = SafetyMaximization(
self.env.stateaction_space)
self.active_sampling_policy = SafetyActiveSampling(
self.env.stateaction_space)
self.keep_seed_in_data = keep_seed_in_data
if not keep_seed_in_data:
self.Q_model.empty_data()
self.violated_soft_constraint = None
self.updated_safety = None
@property
def greed(self):
"""
Returns the epsilon parameter of the ConstrainedEpsilonGreedy policy
:return: epsilon parameter
"""
return self.constrained_value_policy.greed
@greed.setter
def greed(self, new_greed):
"""
Sets the epsilon parameter of the ConstrainedEpsilonGreedy policy
"""
self.constrained_value_policy.greed = new_greed
@property
def step_size(self):
"""
Returns the step_size parameter of the Q-Learning model
:return: step_size parameter
"""
return self.Q_model.step_size
@step_size.setter
def step_size(self, new_step_size):
"""
Sets the epsilon parameter of the ConstrainedEpsilonGreedy policy
"""
self.Q_model.step_size = new_step_size
@property
def gamma_optimistic(self):
return self._gamma_optimistic
@gamma_optimistic.setter
def gamma_optimistic(self, new_gamma_optimistic):
self._gamma_optimistic = new_gamma_optimistic
self.safety_model.gamma_measure = new_gamma_optimistic
def get_next_action(self):
is_cautious_list, proba_slice_list = self.safety_model.level_set(
self.state,
lambda_threshold=[self.lambda_hard, self.lambda_hard],
gamma_threshold=[self.gamma_hard, self.gamma_soft],
return_proba=True,
return_covar=False
)
is_cautious_hard, is_cautious_soft = is_cautious_list
is_cautious_hard = is_cautious_hard.squeeze()
is_cautious_soft = is_cautious_soft.squeeze()
proba_slice_hard = proba_slice_list[0].squeeze()
q_values = self.Q_model[self.state, :]
action = self.constrained_value_policy.get_action(
q_values, is_cautious_hard
)
if action is None:
logger.info('No viable action, taking the safest...')
action = self.safety_maximization_policy.get_action(proba_slice_hard)
self.violated_soft_constraint = True
else:
action_idx = self.env.action_space.get_index_of(action)
self.violated_soft_constraint = not is_cautious_soft[action_idx]
return action
def get_random_safe_state(self):
"""
Returns a random state that is classified as safe by the safety model
:return: a safe state
"""
is_viable = self.safety_model.measure(
slice(None, None, None),
lambda_threshold=self.lambda_hard,
gamma_threshold=self.gamma_hard
) > 0
viable_indexes = np.atleast_1d(np.argwhere(is_viable).squeeze())
try:
state_index = viable_indexes[np.random.choice(len(viable_indexes))]
except Exception as e:
logger.error('ERROR:', str(e))
return None
state = self.env.stateaction_space.state_space[state_index]
return state
def update_models(self, state, action, next_state, reward, failed):
self.Q_model.update(state, action, next_state, reward, failed)
self.safety_model.update(state, action, next_state, reward, failed)
def fit_models(self, q_train_x=None, q_train_y=None, q_epochs=None, q_optimizer_kwargs=None,
s_train_x=None, s_train_y=None, s_epochs=None, s_optimizer_kwargs=None):
if q_train_x is not None:
if q_optimizer_kwargs is None:
q_optimizer_kwargs = {}
self.Q_model.fit(q_train_x, q_train_y, q_epochs, **q_optimizer_kwargs)
if not self.keep_seed_in_data:
self.Q_model.empty_data()
if s_train_x is not None:
if s_optimizer_kwargs is None:
s_optimizer_kwargs = {}
self.safety_model.fit(s_train_x, s_train_y, s_epochs, **s_optimizer_kwargs)
if not self.keep_seed_in_data:
self.safety_model.empty_data()
def step(self):
"""
Chooses an action according to the policy, takes a step in the Environment, and updates the models. The action
taken is available in self.last_action.
:return: new_state, reward, failed
"""
old_state = self.state
action = self.get_next_action()
new_state, reward, failed = self.env.step(action)
if self.violated_soft_constraint or failed:
self.Q_model.update(old_state, action, new_state, reward, failed)
self.safety_model.update(old_state, action, new_state, reward, failed)
self.updated_safety = True
else:
self.Q_model.update(old_state, action, new_state, reward, failed)
self.updated_safety = False
self.state = new_state
self.last_action = action
return new_state, reward, failed, self.env.done