def process(b: int):
# sample bootstrap from batch logged bandit feedback
bandit_feedback = obd.sample_bootstrap_bandit_feedback(random_state=b)
# estimate the mean reward function with an ML model
regression_model = RegressionModel(
n_actions=obd.n_actions,
len_list=obd.len_list,
action_context=obd.action_context,
base_model=base_model_dict[base_model](**hyperparams[base_model]),
)
estimated_rewards_by_reg_model = regression_model.fit_predict(
context=bandit_feedback["context"],
action=bandit_feedback["action"],
reward=bandit_feedback["reward"],
position=bandit_feedback["position"],
pscore=bandit_feedback["pscore"],
n_folds=3, # 3-fold cross-fitting
)
# evaluate estimators' performances using relative estimation error (relative-ee)
ope = OffPolicyEvaluation(
bandit_feedback=bandit_feedback,
ope_estimators=ope_estimators,
)
action_dist = np.tile(action_dist_single_round,
(bandit_feedback["n_rounds"], 1, 1))
relative_ee_b = ope.evaluate_performance_of_estimators(
ground_truth_policy_value=ground_truth_policy_value,
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
)
return relative_ee_b
def process(i: int):
# synthetic data generator
dataset = SyntheticBanditDataset(
n_actions=n_actions,
dim_context=dim_context,
reward_function=logistic_reward_function,
behavior_policy_function=linear_behavior_policy,
random_state=i,
)
# define evaluation policy using IPWLearner
evaluation_policy = IPWLearner(
n_actions=dataset.n_actions,
base_classifier=base_model_dict[base_model_for_evaluation_policy](
**hyperparams[base_model_for_evaluation_policy]
),
)
# sample new training and test sets of synthetic logged bandit feedback
bandit_feedback_train = dataset.obtain_batch_bandit_feedback(n_rounds=n_rounds)
bandit_feedback_test = dataset.obtain_batch_bandit_feedback(n_rounds=n_rounds)
# train the evaluation policy on the training set of the synthetic logged bandit feedback
evaluation_policy.fit(
context=bandit_feedback_train["context"],
action=bandit_feedback_train["action"],
reward=bandit_feedback_train["reward"],
pscore=bandit_feedback_train["pscore"],
)
# predict the action decisions for the test set of the synthetic logged bandit feedback
action_dist = evaluation_policy.predict(
context=bandit_feedback_test["context"],
)
# estimate the mean reward function of the test set of synthetic bandit feedback with ML model
regression_model = RegressionModel(
n_actions=dataset.n_actions,
action_context=dataset.action_context,
base_model=base_model_dict[base_model_for_reg_model](
**hyperparams[base_model_for_reg_model]
),
)
estimated_rewards_by_reg_model = regression_model.fit_predict(
context=bandit_feedback_test["context"],
action=bandit_feedback_test["action"],
reward=bandit_feedback_test["reward"],
n_folds=3, # 3-fold cross-fitting
random_state=random_state,
)
# evaluate estimators' performances using relative estimation error (relative-ee)
ope = OffPolicyEvaluation(
bandit_feedback=bandit_feedback_test,
ope_estimators=ope_estimators,
)
relative_ee_i = ope.evaluate_performance_of_estimators(
ground_truth_policy_value=dataset.calc_ground_truth_policy_value(
expected_reward=bandit_feedback_test["expected_reward"],
action_dist=action_dist,
),
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
)
return relative_ee_i
def test_meta_estimation_format(synthetic_bandit_feedback: BanditFeedback,
random_action_dist: np.ndarray) -> None:
"""
Test the response format of OffPolicyEvaluation
"""
# single ope estimator
ope_ = OffPolicyEvaluation(bandit_feedback=synthetic_bandit_feedback,
ope_estimators=[dm])
assert ope_.estimate_policy_values(random_action_dist) == {
"dm": mock_policy_value
}, "OffPolicyEvaluation.estimate_policy_values ([DirectMethod]) returns a wrong value"
assert ope_.estimate_intervals(random_action_dist) == {
"dm": mock_confidence_interval
}, "OffPolicyEvaluation.estimate_intervals ([DirectMethod]) returns a wrong value"
with pytest.raises(AssertionError,
match=r"action_dist must be 3-dimensional.*"):
ope_.estimate_policy_values(
random_action_dist[:, :, 0]
), "action_dist must be 3-dimensional when using OffPolicyEvaluation"
# multiple ope estimators
ope_ = OffPolicyEvaluation(bandit_feedback=synthetic_bandit_feedback,
ope_estimators=[dm, ipw])
assert ope_.estimate_policy_values(random_action_dist) == {
"dm": mock_policy_value,
"ipw": mock_policy_value + ipw.eps,
}, "OffPolicyEvaluation.estimate_policy_values ([DirectMethod, IPW]) returns a wrong value"
assert ope_.estimate_intervals(random_action_dist) == {
"dm": mock_confidence_interval,
"ipw": {k: v + ipw.eps
for k, v in mock_confidence_interval.items()},
}, "OffPolicyEvaluation.estimate_intervals ([DirectMethod]) returns a wrong value"
def process(i: int):
# sample new data of synthetic logged bandit feedback
bandit_feedback = dataset.obtain_batch_bandit_feedback(
n_rounds=n_rounds)
# simulate the evaluation policy
action_dist = run_bandit_simulation(bandit_feedback=bandit_feedback,
policy=evaluation_policy)
# estimate the ground-truth policy values of the evaluation policy
# by Monte-Carlo Simulation using p(r|x,a), the reward distribution
ground_truth_policy_value = calc_ground_truth_policy_value(
bandit_feedback=bandit_feedback,
reward_sampler=dataset.sample_reward, # p(r|x,a)
policy=evaluation_policy,
n_sim=n_sim, # the number of simulations
)
# evaluate estimators' performances using relative estimation error (relative-ee)
ope = OffPolicyEvaluation(
bandit_feedback=bandit_feedback,
ope_estimators=ope_estimators,
)
relative_ee_i = ope.evaluate_performance_of_estimators(
ground_truth_policy_value=ground_truth_policy_value,
action_dist=action_dist,
)
return relative_ee_i
def test_meta_evaluate_performance_of_estimators_using_invalid_input_data(
action_dist,
estimated_rewards_by_reg_model,
description_1: str,
metric,
ground_truth_policy_value,
description_2: str,
synthetic_bandit_feedback: BanditFeedback,
) -> None:
"""
Test the response of evaluate_performance_of_estimators using invalid data
"""
ope_ = OffPolicyEvaluation(bandit_feedback=synthetic_bandit_feedback,
ope_estimators=[dm])
with pytest.raises(ValueError, match=f"{description_2}*"):
_ = ope_.evaluate_performance_of_estimators(
ground_truth_policy_value=ground_truth_policy_value,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
action_dist=action_dist,
metric=metric,
)
# estimate_intervals function is called in summarize_off_policy_estimates
with pytest.raises(ValueError, match=f"{description_2}*"):
_ = ope_.summarize_estimators_comparison(
ground_truth_policy_value=ground_truth_policy_value,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
action_dist=action_dist,
metric=metric,
)
def process(i: int):
# synthetic data generator with uniformly random policy
dataset = SyntheticBanditDataset(
n_actions=n_actions,
dim_context=dim_context,
reward_function=logistic_reward_function,
behavior_policy_function=None, # uniformly random
random_state=i,
)
# sample new data of synthetic logged bandit feedback
bandit_feedback = dataset.obtain_batch_bandit_feedback(
n_rounds=n_rounds)
# simulate the evaluation policy
action_dist = run_bandit_simulation(bandit_feedback=bandit_feedback,
policy=evaluation_policy)
# estimate the ground-truth policy values of the evaluation policy
# by Monte-Carlo Simulation using p(r|x,a), the reward distribution
ground_truth_policy_value = calc_ground_truth_policy_value(
bandit_feedback=bandit_feedback,
reward_sampler=dataset.sample_reward, # p(r|x,a)
policy=evaluation_policy,
n_sim=n_sim, # the number of simulations
)
# evaluate estimators' performances using relative estimation error (relative-ee)
ope = OffPolicyEvaluation(
bandit_feedback=bandit_feedback,
ope_estimators=ope_estimators,
)
metric_i = ope.evaluate_performance_of_estimators(
ground_truth_policy_value=ground_truth_policy_value,
action_dist=action_dist,
)
return metric_i
def test_meta_estimate_intervals_using_invalid_input_data(
action_dist,
estimated_rewards_by_reg_model,
description_1: str,
alpha,
n_bootstrap_samples,
random_state,
description_2: str,
synthetic_bandit_feedback: BanditFeedback,
) -> None:
"""
Test the response of estimate_intervals using invalid data
"""
ope_ = OffPolicyEvaluation(bandit_feedback=synthetic_bandit_feedback,
ope_estimators=[dm])
with pytest.raises(ValueError, match=f"{description_2}*"):
_ = ope_.estimate_intervals(
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
alpha=alpha,
n_bootstrap_samples=n_bootstrap_samples,
random_state=random_state,
)
# estimate_intervals function is called in summarize_off_policy_estimates
with pytest.raises(ValueError, match=f"{description_2}*"):
_ = ope_.summarize_off_policy_estimates(
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
alpha=alpha,
n_bootstrap_samples=n_bootstrap_samples,
random_state=random_state,
)
def test_meta_post_init(synthetic_bandit_feedback: BanditFeedback) -> None:
"""
Test the __post_init__ function
"""
# __post_init__ saves the latter estimator when the same estimator name is used
ope_ = OffPolicyEvaluation(bandit_feedback=synthetic_bandit_feedback,
ope_estimators=[ipw, ipw2])
assert ope_.ope_estimators_ == {
"ipw": ipw2
}, "__post_init__ returns a wrong value"
# __post_init__ can handle the same estimator if the estimator names are different
ope_ = OffPolicyEvaluation(bandit_feedback=synthetic_bandit_feedback,
ope_estimators=[ipw, ipw3])
assert ope_.ope_estimators_ == {
"ipw": ipw,
"ipw3": ipw3,
}, "__post_init__ returns a wrong value"
# __post__init__ raises RuntimeError when necessary_keys are not included in the bandit_feedback
necessary_keys = ["action", "position", "reward", "pscore"]
for i in range(len(necessary_keys)):
for deleted_keys in itertools.combinations(necessary_keys, i + 1):
invalid_bandit_feedback_dict = {key: "_" for key in necessary_keys}
# delete
for k in deleted_keys:
del invalid_bandit_feedback_dict[k]
with pytest.raises(RuntimeError, match=r"Missing key*"):
_ = OffPolicyEvaluation(
bandit_feedback=invalid_bandit_feedback_dict,
ope_estimators=[ipw])
def test_meta_evaluate_performance_of_estimators_using_valid_input_data(
action_dist,
estimated_rewards_by_reg_model,
description_1: str,
metric,
ground_truth_policy_value,
description_2: str,
synthetic_bandit_feedback: BanditFeedback,
) -> None:
"""
Test the response of evaluate_performance_of_estimators using valid data
"""
if metric == "relative-ee":
# calculate relative-ee
eval_metric_ope_dict = {
"ipw":
np.abs((mock_policy_value + ipw.eps - ground_truth_policy_value) /
ground_truth_policy_value),
"ipw3":
np.abs((mock_policy_value + ipw3.eps - ground_truth_policy_value) /
ground_truth_policy_value),
}
else:
# calculate se
eval_metric_ope_dict = {
"ipw":
(mock_policy_value + ipw.eps - ground_truth_policy_value)**2,
"ipw3":
(mock_policy_value + ipw3.eps - ground_truth_policy_value)**2,
}
# check performance estimators
ope_ = OffPolicyEvaluation(bandit_feedback=synthetic_bandit_feedback,
ope_estimators=[ipw, ipw3])
performance = ope_.evaluate_performance_of_estimators(
ground_truth_policy_value=ground_truth_policy_value,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
action_dist=action_dist,
metric=metric,
)
for k, v in performance.items():
assert k in eval_metric_ope_dict, "Invalid key of performance response"
assert v == eval_metric_ope_dict[
k], "Invalid value of performance response"
performance_df = ope_.summarize_estimators_comparison(
ground_truth_policy_value=ground_truth_policy_value,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
action_dist=action_dist,
metric=metric,
)
assert_frame_equal(
performance_df,
pd.DataFrame(eval_metric_ope_dict,
index=[metric]).T), "Invalid summarization (performance)"
def process(i: int):
# sample new training and test sets of synthetic logged bandit feedback
bandit_feedback_train = dataset.obtain_batch_bandit_feedback(
n_rounds=n_rounds)
bandit_feedback_test = dataset.obtain_batch_bandit_feedback(
n_rounds=n_rounds)
# train the evaluation policy on the training set of the synthetic logged bandit feedback
evaluation_policy.fit(
context=bandit_feedback_train["context"],
action=bandit_feedback_train["action"],
reward=bandit_feedback_train["reward"],
pscore=bandit_feedback_train["pscore"],
)
# predict the action decisions for the test set of the synthetic logged bandit feedback
action_dist = evaluation_policy.predict_proba(
context=bandit_feedback_test["context"],
tau=0.1, # temperature hyperparameter
)
# estimate the ground-truth policy values of the evaluation policy
# using the full expected reward contained in the test set of synthetic bandit feedback
ground_truth_policy_value = np.average(
bandit_feedback_test["expected_reward"],
weights=action_dist[:, :, 0],
axis=1,
).mean()
# estimate the mean reward function of the test set of synthetic bandit feedback with ML model
regression_model = RegressionModel(
n_actions=dataset.n_actions,
len_list=dataset.len_list,
action_context=dataset.action_context,
base_model=base_model_dict[base_model_for_reg_model](
**hyperparams[base_model_for_reg_model]),
)
estimated_rewards_by_reg_model = regression_model.fit_predict(
context=bandit_feedback_test["context"],
action=bandit_feedback_test["action"],
reward=bandit_feedback_test["reward"],
n_folds=3, # 3-fold cross-fitting
random_state=random_state,
)
# evaluate estimators' performances using relative estimation error (relative-ee)
ope = OffPolicyEvaluation(
bandit_feedback=bandit_feedback_test,
ope_estimators=ope_estimators,
)
relative_ee_i = ope.evaluate_performance_of_estimators(
ground_truth_policy_value=ground_truth_policy_value,
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
)
return relative_ee_i
def test_meta_estimate_policy_values_using_valid_input_data(
action_dist,
estimated_rewards_by_reg_model,
description: str,
synthetic_bandit_feedback: BanditFeedback,
) -> None:
"""
Test the response of estimate_policy_values using valid data
"""
# single ope estimator
ope_ = OffPolicyEvaluation(
bandit_feedback=synthetic_bandit_feedback, ope_estimators=[dm]
)
ope_.is_model_dependent = True
assert ope_.estimate_policy_values(
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
) == {
"dm": mock_policy_value
}, "OffPolicyEvaluation.estimate_policy_values ([DirectMethod]) returns a wrong value"
# multiple ope estimators
ope_ = OffPolicyEvaluation(
bandit_feedback=synthetic_bandit_feedback, ope_estimators=[dm, ipw]
)
ope_.is_model_dependent = True
assert ope_.estimate_policy_values(
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
) == {
"dm": mock_policy_value,
"ipw": mock_policy_value + ipw.eps,
}, "OffPolicyEvaluation.estimate_policy_values ([DirectMethod, IPW]) returns a wrong value"
def process(b: int):
# load the pre-trained regression model
with open(reg_model_path / f"reg_model_{b}.pkl", "rb") as f:
reg_model = pickle.load(f)
with open(reg_model_path / f"reg_model_mrdr_{b}.pkl", "rb") as f:
reg_model_mrdr = pickle.load(f)
with open(reg_model_path / f"is_for_reg_model_{b}.pkl", "rb") as f:
is_for_reg_model = pickle.load(f)
# sample bootstrap samples from batch logged bandit feedback
if is_timeseries_split:
bandit_feedback = obd.sample_bootstrap_bandit_feedback(
test_size=test_size,
is_timeseries_split=is_timeseries_split,
random_state=b,
)
else:
bandit_feedback = obd.sample_bootstrap_bandit_feedback(
test_size=test_size,
is_timeseries_split=is_timeseries_split,
random_state=b,
)
bandit_feedback["n_rounds"] = (~is_for_reg_model).sum()
for key_ in ["context", "action", "reward", "pscore", "position"]:
bandit_feedback[key_] = bandit_feedback[key_][
~is_for_reg_model]
# estimate the mean reward function using the pre-trained reg_model
estimated_rewards_by_reg_model_default = reg_model.predict(
context=bandit_feedback["context"], )
estimated_rewards_by_reg_model_mrdr = reg_model_mrdr.predict(
context=bandit_feedback["context"], )
estimated_rewards_by_reg_model = {
estimator.estimator_name:
estimated_rewards_by_reg_model_mrdr if estimator.estimator_name
== "mrdr" else estimated_rewards_by_reg_model_default
for estimator in ope_estimators
}
# evaluate the estimation performance of OPE estimators
ope = OffPolicyEvaluation(
bandit_feedback=bandit_feedback,
ope_estimators=ope_estimators,
)
action_dist = np.tile(action_dist_single_round,
(bandit_feedback["n_rounds"], 1, 1))
relative_ee_b = ope.evaluate_performance_of_estimators(
ground_truth_policy_value=ground_truth_policy_value,
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
)
return relative_ee_b
def test_response_format_of_ope_estimators_using_random_evaluation_policy(
synthetic_bandit_feedback: BanditFeedback,
random_action_dist: np.ndarray) -> None:
"""
Test the response format of ope estimators using synthetic bandit data and random evaluation policy
"""
expected_reward = synthetic_bandit_feedback["expected_reward"][:, :,
np.newaxis]
action_dist = random_action_dist
# test all estimators
all_estimators = ope.__all_estimators__
estimators = [
getattr(ope.estimators, estimator_name)()
for estimator_name in all_estimators
]
# conduct OPE
ope_instance = OffPolicyEvaluation(
bandit_feedback=synthetic_bandit_feedback, ope_estimators=estimators)
estimated_policy_value = ope_instance.estimate_policy_values(
action_dist=action_dist,
estimated_rewards_by_reg_model=expected_reward)
estimated_intervals = ope_instance.estimate_intervals(
action_dist=action_dist,
estimated_rewards_by_reg_model=expected_reward,
random_state=12345,
)
# check the format of OPE
for key in estimated_policy_value:
# check the keys of the output dictionary of the estimate_intervals method
assert set(estimated_intervals[key].keys()) == set([
"mean", "95.0% CI (lower)", "95.0% CI (upper)"
]), f"Confidence interval of {key} has invalid keys"
# check the relationship between the means and the confidence bounds estimated by OPE estimators
assert (
estimated_intervals[key]["95.0% CI (lower)"] <=
estimated_policy_value[key]
) and (
estimated_intervals[key]["95.0% CI (upper)"] >=
estimated_policy_value[key]
), f"Estimated policy value of {key} is not included in estimated intervals of that estimator"
assert (estimated_intervals[key]["mean"] >=
estimated_intervals[key]["95.0% CI (lower)"]
), f"Invalid confidence interval of {key}: lower bound > mean"
assert (estimated_intervals[key]["mean"] <=
estimated_intervals[key]["95.0% CI (upper)"]
), f"Invalid confidence interval of {key}: upper bound < mean"
def test_meta_create_estimator_inputs_using_valid_input_data(
action_dist,
estimated_rewards_by_reg_model,
description: str,
synthetic_bandit_feedback: BanditFeedback,
) -> None:
"""
Test the _create_estimator_inputs using invalid data
"""
ope_ = OffPolicyEvaluation(
bandit_feedback=synthetic_bandit_feedback, ope_estimators=[ipw]
)
estimator_inputs = ope_._create_estimator_inputs(
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
)
assert set(estimator_inputs.keys()) == set(["ipw"])
assert set(estimator_inputs["ipw"].keys()) == set(
[
"reward",
"action",
"pscore",
"position",
"action_dist",
"estimated_rewards_by_reg_model",
"estimated_pscore",
"estimated_importance_weights",
"p_e_a",
"pi_b",
"context",
"action_embed",
]
), f"Invalid response of _create_estimator_inputs (test case: {description})"
# _create_estimator_inputs function is called in the following functions
_ = ope_.estimate_policy_values(
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
)
_ = ope_.estimate_intervals(
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
)
_ = ope_.summarize_off_policy_estimates(
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
)
_ = ope_.evaluate_performance_of_estimators(
ground_truth_policy_value=0.1,
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
)
_ = ope_.summarize_estimators_comparison(
ground_truth_policy_value=0.1,
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
)
def test_meta_post_init_format(synthetic_bandit_feedback: BanditFeedback,
random_action_dist: np.ndarray) -> None:
"""
Test the post init format of OffPolicyEvaluation
"""
# __post_init__ saves the latter estimator when the same estimator name is used
ope_ = OffPolicyEvaluation(bandit_feedback=synthetic_bandit_feedback,
ope_estimators=[ipw, ipw2])
assert ope_.ope_estimators_ == {
"ipw": ipw2
}, "__post_init__ returns a wrong value"
# __post_init__ can handle the same estimator if the estimator names are different
ope_ = OffPolicyEvaluation(bandit_feedback=synthetic_bandit_feedback,
ope_estimators=[ipw, ipw3])
assert ope_.ope_estimators_ == {
"ipw": ipw,
"ipw3": ipw3,
}, "__post_init__ returns a wrong value"
def test_meta_create_estimator_inputs_format(
synthetic_bandit_feedback: BanditFeedback,
random_action_dist: np.ndarray) -> None:
"""
Test the _create_estimator_inputs format of OffPolicyEvaluation
"""
# __post_init__ saves the latter estimator when the same estimator name is used
ope_ = OffPolicyEvaluation(bandit_feedback=synthetic_bandit_feedback,
ope_estimators=[ipw])
inputs = ope_._create_estimator_inputs(action_dist=None,
estimated_rewards_by_reg_model=None)
assert set(inputs.keys()) == set([
"reward",
"action",
"pscore",
"position",
"action_dist",
"estimated_rewards_by_reg_model",
]), "Invalid response format of _create_estimator_inputs"
def test_performance_of_ope_estimators_using_random_evaluation_policy(
synthetic_bandit_feedback: BanditFeedback,
random_action_dist: np.ndarray) -> None:
"""
Test the performance of ope estimators using synthetic bandit data and random evaluation policy
"""
expected_reward = synthetic_bandit_feedback["expected_reward"][:, :,
np.newaxis]
action_dist = random_action_dist
# compute ground truth policy value using expected reward
q_pi_e = np.average(expected_reward[:, :, 0],
weights=action_dist[:, :, 0],
axis=1)
# compute statistics of ground truth policy value
gt_mean = q_pi_e.mean()
gt_std = q_pi_e.std(ddof=1)
# test most of the estimators (ReplayMethod is not tested because it is out of scope)
all_estimators = ope.__all_estimators__
estimators = [
getattr(ope.estimators, estimator_name)()
for estimator_name in all_estimators
if estimator_name not in ["ReplayMethod"]
]
# conduct OPE
ope_instance = OffPolicyEvaluation(
bandit_feedback=synthetic_bandit_feedback, ope_estimators=estimators)
estimated_policy_value = ope_instance.estimate_policy_values(
action_dist=action_dist,
estimated_rewards_by_reg_model=expected_reward)
# check the performance of OPE
ci_bound = gt_std * 3 / np.sqrt(q_pi_e.shape[0])
print(f"gt_mean: {gt_mean}, 3 * gt_std / sqrt(n): {ci_bound}")
for key in estimated_policy_value:
print(
f"estimated_value: {estimated_policy_value[key]} ------ estimator: {key}, "
)
# test the performance of each estimator
assert (
np.abs(gt_mean - estimated_policy_value[key]) <= ci_bound
), f"OPE of {key} did not work well (absolute error is greater than 3*sigma)"
def process(i: int):
# split the original data into training and evaluation sets
dataset.split_train_eval(eval_size=eval_size, random_state=i)
# obtain logged bandit feedback generated by behavior policy
bandit_feedback = dataset.obtain_batch_bandit_feedback(random_state=i)
# obtain action choice probabilities by an evaluation policy
action_dist = dataset.obtain_action_dist_by_eval_policy(
base_classifier_e=base_model_dict[base_model_for_evaluation_policy]
(**hyperparams[base_model_for_evaluation_policy]),
alpha_e=alpha_e,
)
# calculate the ground-truth performance of the evaluation policy
ground_truth_policy_value = dataset.calc_ground_truth_policy_value(
action_dist=action_dist)
# estimate the mean reward function of the evaluation set of multi-class classification data with ML model
regression_model = RegressionModel(
n_actions=dataset.n_actions,
base_model=base_model_dict[base_model_for_reg_model](
**hyperparams[base_model_for_reg_model]),
)
estimated_rewards_by_reg_model = regression_model.fit_predict(
context=bandit_feedback["context"],
action=bandit_feedback["action"],
reward=bandit_feedback["reward"],
n_folds=3, # 3-fold cross-fitting
random_state=random_state,
)
# evaluate estimators' performances using relative estimation error (relative-ee)
ope = OffPolicyEvaluation(
bandit_feedback=bandit_feedback,
ope_estimators=ope_estimators,
)
relative_ee_i = ope.evaluate_performance_of_estimators(
ground_truth_policy_value=ground_truth_policy_value,
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
)
return relative_ee_i
def test_meta_evaluate_performance_of_estimators(
synthetic_bandit_feedback: BanditFeedback,
random_action_dist: np.ndarray) -> None:
gt = 0.5
# calculate relative-ee
eval_metric_ope_dict = {
"ipw": np.abs((mock_policy_value + ipw.eps - gt) / gt),
"ipw3": np.abs((mock_policy_value + ipw3.eps - gt) / gt),
}
# check performance estimators
ope_ = OffPolicyEvaluation(bandit_feedback=synthetic_bandit_feedback,
ope_estimators=[ipw, ipw3])
performance = ope_.evaluate_performance_of_estimators(
ground_truth_policy_value=gt,
action_dist=random_action_dist,
metric="relative-ee",
)
for k, v in performance.items():
assert k in eval_metric_ope_dict, "Invalid key of performance response"
assert v == eval_metric_ope_dict[
k], "Invalid value of performance response"
# zero division error when using relative-ee
with pytest.raises(ZeroDivisionError, match=r"float division by zero"):
_ = ope_.evaluate_performance_of_estimators(
ground_truth_policy_value=0.0,
action_dist=random_action_dist,
metric="relative-ee",
)
# check summarization
performance_df = ope_.summarize_estimators_comparison(
ground_truth_policy_value=gt,
action_dist=random_action_dist,
metric="relative-ee",
)
assert_frame_equal(
performance_df,
pd.DataFrame(eval_metric_ope_dict,
index=["relative-ee"
]).T), "Invalid summarization (performance)"
def test_meta_summarize_off_policy_estimates(
synthetic_bandit_feedback: BanditFeedback,
random_action_dist: np.ndarray) -> None:
ope_ = OffPolicyEvaluation(bandit_feedback=synthetic_bandit_feedback,
ope_estimators=[ipw, ipw3])
value, interval = ope_.summarize_off_policy_estimates(random_action_dist)
expected_value = pd.DataFrame(
{
"ipw": mock_policy_value + ipw.eps,
"ipw3": mock_policy_value + ipw3.eps,
},
index=["estimated_policy_value"],
).T
expected_interval = pd.DataFrame({
"ipw": {k: v + ipw.eps
for k, v in mock_confidence_interval.items()},
"ipw3": {k: v + ipw3.eps
for k, v in mock_confidence_interval.items()},
}).T
assert_frame_equal(value,
expected_value), "Invalid summarization (policy value)"
assert_frame_equal(interval,
expected_interval), "Invalid summarization (interval)"
def test_meta_create_estimator_inputs_using_invalid_input_data(
action_dist,
estimated_rewards_by_reg_model,
description: str,
synthetic_bandit_feedback: BanditFeedback,
) -> None:
"""
Test the _create_estimator_inputs using valid data
"""
ope_ = OffPolicyEvaluation(
bandit_feedback=synthetic_bandit_feedback, ope_estimators=[ipw]
)
# raise ValueError when the shape of two arrays are different
with pytest.raises(ValueError, match=f"{description}*"):
_ = ope_._create_estimator_inputs(
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
)
# _create_estimator_inputs function is called in the following functions
with pytest.raises(ValueError, match=f"{description}*"):
_ = ope_.estimate_policy_values(
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
)
with pytest.raises(ValueError, match=f"{description}*"):
_ = ope_.estimate_intervals(
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
)
with pytest.raises(ValueError, match=f"{description}*"):
_ = ope_.summarize_off_policy_estimates(
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
)
with pytest.raises(ValueError, match=f"{description}*"):
_ = ope_.evaluate_performance_of_estimators(
ground_truth_policy_value=0.1,
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
)
with pytest.raises(ValueError, match=f"{description}*"):
_ = ope_.summarize_estimators_comparison(
ground_truth_policy_value=0.1,
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
)
def test_meta_estimate_intervals_using_valid_input_data(
action_dist,
estimated_rewards_by_reg_model,
description_1: str,
alpha: float,
n_bootstrap_samples: int,
random_state: int,
description_2: str,
synthetic_bandit_feedback: BanditFeedback,
) -> None:
"""
Test the response of estimate_intervals using valid data
"""
# single ope estimator
ope_ = OffPolicyEvaluation(
bandit_feedback=synthetic_bandit_feedback, ope_estimators=[dm]
)
assert ope_.estimate_intervals(
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
alpha=alpha,
n_bootstrap_samples=n_bootstrap_samples,
random_state=random_state,
) == {
"dm": mock_confidence_interval
}, "OffPolicyEvaluation.estimate_intervals ([DirectMethod]) returns a wrong value"
# multiple ope estimators
ope_ = OffPolicyEvaluation(
bandit_feedback=synthetic_bandit_feedback, ope_estimators=[dm, ipw]
)
assert ope_.estimate_intervals(
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
alpha=alpha,
n_bootstrap_samples=n_bootstrap_samples,
random_state=random_state,
) == {
"dm": mock_confidence_interval,
"ipw": {k: v + ipw.eps for k, v in mock_confidence_interval.items()},
}, "OffPolicyEvaluation.estimate_intervals ([DirectMethod, IPW]) returns a wrong value"
def test_meta_estimated_rewards_by_reg_model_inputs(
synthetic_bandit_feedback: BanditFeedback,
) -> None:
"""
Test the estimate_policy_values/estimate_intervals functions wrt estimated_rewards_by_reg_model
"""
ope_ = OffPolicyEvaluation(
bandit_feedback=synthetic_bandit_feedback, ope_estimators=[DirectMethod()]
)
action_dist = np.zeros(
(synthetic_bandit_feedback["n_rounds"], synthetic_bandit_feedback["n_actions"])
)
with pytest.raises(ValueError):
ope_.estimate_policy_values(
action_dist=action_dist,
estimated_rewards_by_reg_model=None,
)
with pytest.raises(ValueError):
ope_.estimate_intervals(
action_dist=action_dist,
estimated_rewards_by_reg_model=None,
)
def test_performance_of_ope_estimators_using_random_evaluation_policy(
synthetic_bandit_feedback: BanditFeedback, random_action_dist: np.ndarray
) -> None:
"""
Test the performance of ope estimators using synthetic bandit data and random evaluation policy
"""
expected_reward = synthetic_bandit_feedback["expected_reward"][:, :, np.newaxis]
action_dist = random_action_dist
# compute ground truth policy value using expected reward
q_pi_e = np.average(expected_reward[:, :, 0], weights=action_dist[:, :, 0], axis=1)
# compute statistics of ground truth policy value
gt_mean = q_pi_e.mean()
# test most of the estimators (ReplayMethod is not tested because it is out of scope)
all_estimators = ope.__all_estimators__
estimators_standard = [
getattr(ope.estimators, estimator_name)()
for estimator_name in all_estimators
if estimator_name not in ["ReplayMethod"]
]
all_estimators_tuning = ope.__all_estimators_tuning__
estimators_tuning = [
getattr(ope.estimators_tuning, estimator_name)(
lambdas=[1, 100, 10000, np.inf],
tuning_method=tuning_method,
)
for estimator_name in all_estimators_tuning
for tuning_method in ["slope", "mse"]
]
all_estimators_tuning_sg = ope.__all_estimators_tuning_sg__
estimators_tuning_sg = [
getattr(ope.estimators_tuning, estimator_name)(
lambdas=[0.001, 0.01, 0.1, 1.0],
tuning_method=tuning_method,
)
for estimator_name in all_estimators_tuning_sg
for tuning_method in ["slope", "mse"]
]
estimators = estimators_standard + estimators_tuning + estimators_tuning_sg
# skip estimation
estimated_pscore = None
estimated_importance_weights = (
random_action_dist[
np.arange(synthetic_bandit_feedback["action"].shape[0]),
synthetic_bandit_feedback["action"],
np.zeros(
synthetic_bandit_feedback["action"].shape[0], dtype=int
), # position is None
]
/ synthetic_bandit_feedback["pscore"]
)
# conduct OPE
ope_instance = OffPolicyEvaluation(
bandit_feedback=synthetic_bandit_feedback, ope_estimators=estimators
)
estimated_policy_value = ope_instance.estimate_policy_values(
action_dist=action_dist,
estimated_rewards_by_reg_model=expected_reward,
estimated_pscore=estimated_pscore,
estimated_importance_weights=estimated_importance_weights,
)
# check the performance of OPE
print(f"gt_mean: {gt_mean}")
for key in estimated_policy_value:
print(
f"estimated_value: {estimated_policy_value[key]} ------ estimator: {key}, "
)
# test the performance of each estimator
assert (
np.abs(gt_mean - estimated_policy_value[key]) / gt_mean <= 0.1
), f"OPE of {key} did not work well (relative absolute error is greater than 10%)"
# ground-truth policy value of the random policy
# , which is the empirical mean of the factual (observed) rewards (on-policy estimation)
ground_truth = bandit_feedback["reward"].mean()
# a base ML model for regression model used in Direct Method and Doubly Robust
base_model = CalibratedClassifierCV(
HistGradientBoostingClassifier(**hyperparams))
# run a counterfactual bandit algorithm on logged bandit feedback data
selected_actions = run_bandit_simulation(bandit_feedback=bandit_feedback,
policy=policy)
# estimate the policy value of a given counterfactual algorithm by the three OPE estimators.
ope = OffPolicyEvaluation(
bandit_feedback=bandit_feedback,
regression_model=RegressionModel(base_model=base_model),
action_context=obd.action_context,
ope_estimators=[
InverseProbabilityWeighting(),
DirectMethod(),
DoublyRobust()
],
)
estimated_policy_value, estimated_interval = ope.summarize_off_policy_estimates(
selected_actions=selected_actions)
# calculate estimated policy value relative to that of the behavior policy
print("=" * 70)
print(f"random_state={random_state}: counterfactual policy={policy_name}")
print("-" * 70)
estimated_policy_value["relative_estimated_policy_value"] = (
estimated_policy_value.estimated_policy_value / ground_truth)
print(estimated_policy_value)
print("=" * 70)
def process(i: int):
# synthetic data generator
dataset = SyntheticBanditDatasetWithActionEmbeds(
n_actions=n_actions,
dim_context=dim_context,
beta=3.0,
n_cat_dim=3,
n_cat_per_dim=5,
reward_function=logistic_reward_function,
random_state=i,
)
# define evaluation policy using IPWLearner
evaluation_policy = IPWLearner(
n_actions=dataset.n_actions,
base_classifier=base_model_dict[base_model_for_iw_estimator](
**hyperparams[base_model_for_iw_estimator]),
)
# sample new training and test sets of synthetic logged bandit data
bandit_feedback_train = dataset.obtain_batch_bandit_feedback(
n_rounds=n_rounds)
bandit_feedback_test = dataset.obtain_batch_bandit_feedback(
n_rounds=n_rounds)
# train the evaluation policy on the training set of the synthetic logged bandit data
evaluation_policy.fit(
context=bandit_feedback_train["context"],
action=bandit_feedback_train["action"],
reward=bandit_feedback_train["reward"],
pscore=bandit_feedback_train["pscore"],
)
# predict the action decisions for the test set of the synthetic logged bandit data
action_dist = evaluation_policy.predict_proba(
context=bandit_feedback_test["context"], )
# estimate the reward function of the test set of synthetic bandit feedback with ML model
regression_model = RegressionModel(
n_actions=dataset.n_actions,
action_context=dataset.action_context,
base_model=base_model_dict[base_model_for_reg_model](
**hyperparams[base_model_for_reg_model]),
)
estimated_rewards_by_reg_model = regression_model.fit_predict(
context=bandit_feedback_test["context"],
action=bandit_feedback_test["action"],
reward=bandit_feedback_test["reward"],
n_folds=2,
random_state=12345,
)
# fit propensity score estimators
pscore_estimator = PropensityScoreEstimator(
len_list=1,
n_actions=n_actions,
base_model=base_model_dict[base_model_for_pscore_estimator](
**hyperparams[base_model_for_pscore_estimator]),
calibration_cv=3,
)
estimated_pscore = pscore_estimator.fit_predict(
action=bandit_feedback_test["action"],
position=bandit_feedback_test["position"],
context=bandit_feedback_test["context"],
n_folds=3,
random_state=12345,
)
# fit importance weight estimators
estimated_importance_weights_dict = {}
for clf_name, clf_arguments in bipw_model_configurations.items():
clf = ImportanceWeightEstimator(
len_list=1,
n_actions=n_actions,
fitting_method=clf_arguments["fitting_method"],
base_model=clf_arguments["base_model"],
)
estimated_importance_weights_dict[clf_name] = clf.fit_predict(
action=bandit_feedback_test["action"],
context=bandit_feedback_test["context"],
action_dist=action_dist,
position=bandit_feedback_test["position"],
n_folds=2,
evaluate_model_performance=False,
random_state=12345,
)
# evaluate estimators' performances using relative estimation error (relative-ee)
ope = OffPolicyEvaluation(
bandit_feedback=bandit_feedback_test,
ope_estimators=ope_estimators + [
MarginalizedInverseProbabilityWeighting(n_actions=n_actions,
estimator_name="mipw"),
MarginalizedInverseProbabilityWeighting(
n_actions=n_actions,
embedding_selection_method="greedy",
estimator_name="mipw (greedy selection)",
),
SelfNormalizedMarginalizedInverseProbabilityWeighting(
n_actions=n_actions, estimator_name="snmipw"),
],
)
relative_ee_i = ope.evaluate_performance_of_estimators(
ground_truth_policy_value=dataset.calc_ground_truth_policy_value(
expected_reward=bandit_feedback_test["expected_reward"],
action_dist=action_dist,
),
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
estimated_pscore=estimated_pscore,
estimated_importance_weights=estimated_importance_weights_dict,
action_embed=bandit_feedback_test["action_embed"],
pi_b=bandit_feedback_test["pi_b"],
metric="relative-ee",
)
return relative_ee_i
)
evaluation_of_ope_results = {
est.estimator_name: np.zeros(n_boot_samples) for est in ope_estimators
}
for b in np.arange(n_boot_samples):
# sample bootstrap from batch logged bandit feedback
boot_bandit_feedback = obd.sample_bootstrap_bandit_feedback(random_state=b)
# run a counterfactual bandit algorithm on logged bandit feedback data
selected_actions = run_bandit_simulation(
bandit_feedback=boot_bandit_feedback, policy=policy
)
# evaluate the estimation performance of OPE estimators
ope = OffPolicyEvaluation(
bandit_feedback=boot_bandit_feedback,
action_context=obd.action_context,
regression_model=RegressionModel(base_model=base_model),
ope_estimators=ope_estimators,
)
relative_estimation_errors = ope.evaluate_performance_of_estimators(
selected_actions=selected_actions,
ground_truth_policy_value=ground_truth_policy_value,
)
policy.initialize()
# store relative estimation errors of OPE estimators at each split
for (
estimator_name,
relative_estimation_error,
) in relative_estimation_errors.items():
evaluation_of_ope_results[estimator_name][b] = relative_estimation_error
# estimate confidence intervals of relative estimation by nonparametric bootstrap method
def test_response_format_of_ope_estimators_using_random_evaluation_policy(
synthetic_bandit_feedback: BanditFeedback, random_action_dist: np.ndarray
) -> None:
"""
Test the response format of ope estimators using synthetic bandit data and random evaluation policy
"""
expected_reward = synthetic_bandit_feedback["expected_reward"][:, :, np.newaxis]
action_dist = random_action_dist
# test all estimators
all_estimators = ope.__all_estimators__
estimators_standard = [
getattr(ope.estimators, estimator_name)() for estimator_name in all_estimators
]
all_estimators_tuning = ope.__all_estimators_tuning__
estimators_tuning = [
getattr(ope.estimators_tuning, estimator_name)(
lambdas=[1, 100, 10000, np.inf],
tuning_method=tuning_method,
)
for estimator_name in all_estimators_tuning
for tuning_method in ["slope", "mse"]
]
all_estimators_tuning_sg = ope.__all_estimators_tuning_sg__
estimators_tuning_sg = [
getattr(ope.estimators_tuning, estimator_name)(
lambdas=[0.001, 0.01, 0.1, 1.0],
tuning_method=tuning_method,
)
for estimator_name in all_estimators_tuning_sg
for tuning_method in ["slope", "mse"]
]
estimators = estimators_standard + estimators_tuning + estimators_tuning_sg
# skip estimation
estimated_pscore = None
estimated_importance_weights = (
random_action_dist[
np.arange(synthetic_bandit_feedback["action"].shape[0]),
synthetic_bandit_feedback["action"],
np.zeros(
synthetic_bandit_feedback["action"].shape[0], dtype=int
), # position is None
]
/ synthetic_bandit_feedback["pscore"]
)
# conduct OPE
ope_instance = OffPolicyEvaluation(
bandit_feedback=synthetic_bandit_feedback, ope_estimators=estimators
)
estimated_policy_value = ope_instance.estimate_policy_values(
action_dist=action_dist,
estimated_rewards_by_reg_model=expected_reward,
estimated_pscore=estimated_pscore,
estimated_importance_weights=estimated_importance_weights,
)
estimated_intervals = ope_instance.estimate_intervals(
action_dist=action_dist,
estimated_rewards_by_reg_model=expected_reward,
estimated_pscore=estimated_pscore,
estimated_importance_weights=estimated_importance_weights,
random_state=12345,
)
# check the format of OPE
for key in estimated_policy_value:
# check the keys of the output dictionary of the estimate_intervals method
assert set(estimated_intervals[key].keys()) == set(
["mean", "95.0% CI (lower)", "95.0% CI (upper)"]
), f"Confidence interval of {key} has invalid keys"
# check the relationship between the means and the confidence bounds estimated by OPE estimators
assert (
estimated_intervals[key]["95.0% CI (lower)"] <= estimated_policy_value[key]
) and (
estimated_intervals[key]["95.0% CI (upper)"] >= estimated_policy_value[key]
), f"Estimated policy value of {key} is not included in estimated intervals of that estimator"
assert (
estimated_intervals[key]["mean"]
>= estimated_intervals[key]["95.0% CI (lower)"]
), f"Invalid confidence interval of {key}: lower bound > mean"
assert (
estimated_intervals[key]["mean"]
<= estimated_intervals[key]["95.0% CI (upper)"]
), f"Invalid confidence interval of {key}: upper bound < mean"
def test_meta_summarize_off_policy_estimates(
action_dist,
estimated_rewards_by_reg_model,
description_1: str,
alpha: float,
n_bootstrap_samples: int,
random_state: int,
description_2: str,
synthetic_bandit_feedback: BanditFeedback,
) -> None:
"""
Test the response of summarize_off_policy_estimates using valid data
"""
ope_ = OffPolicyEvaluation(bandit_feedback=synthetic_bandit_feedback,
ope_estimators=[ipw, ipw3])
value, interval = ope_.summarize_off_policy_estimates(
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
alpha=alpha,
n_bootstrap_samples=n_bootstrap_samples,
random_state=random_state,
)
expected_value = pd.DataFrame(
{
"ipw": mock_policy_value + ipw.eps,
"ipw3": mock_policy_value + ipw3.eps,
},
index=["estimated_policy_value"],
).T
expected_value["relative_estimated_policy_value"] = (
expected_value["estimated_policy_value"] /
synthetic_bandit_feedback["reward"].mean())
expected_interval = pd.DataFrame({
"ipw": {k: v + ipw.eps
for k, v in mock_confidence_interval.items()},
"ipw3": {k: v + ipw3.eps
for k, v in mock_confidence_interval.items()},
}).T
assert_frame_equal(value,
expected_value), "Invalid summarization (policy value)"
assert_frame_equal(interval,
expected_interval), "Invalid summarization (interval)"
# check relative estimated policy value when the average of bandit_feedback["reward"] is zero
zero_reward_bandit_feedback = deepcopy(synthetic_bandit_feedback)
zero_reward_bandit_feedback["reward"] = np.zeros(
zero_reward_bandit_feedback["reward"].shape[0])
ope_ = OffPolicyEvaluation(bandit_feedback=zero_reward_bandit_feedback,
ope_estimators=[ipw, ipw3])
value, _ = ope_.summarize_off_policy_estimates(
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
alpha=alpha,
n_bootstrap_samples=n_bootstrap_samples,
random_state=random_state,
)
expected_value = pd.DataFrame(
{
"ipw": mock_policy_value + ipw.eps,
"ipw3": mock_policy_value + ipw3.eps,
},
index=["estimated_policy_value"],
).T
expected_value["relative_estimated_policy_value"] = np.nan
assert_frame_equal(value,
expected_value), "Invalid summarization (policy value)"
action_dist = policy.compute_batch_action_dist(
n_sim=100000, n_rounds=boot_bandit_feedback["n_rounds"])
else:
policy = Random(
n_actions=obd.n_actions,
len_list=obd.len_list,
random_state=random_state,
)
action_dist = policy.compute_batch_action_dist(
n_sim=100000, n_rounds=boot_bandit_feedback["n_rounds"])
# estimate the mean reward function using the pre-trained reg_model
estimated_rewards_by_reg_model = reg_model.predict(
context=boot_bandit_feedback["context"], )
# evaluate the estimation performance of OPE estimators
ope = OffPolicyEvaluation(
bandit_feedback=boot_bandit_feedback,
ope_estimators=ope_estimators,
)
relative_estimation_errors = ope.evaluate_performance_of_estimators(
ground_truth_policy_value=ground_truth_policy_value,
action_dist=action_dist,
estimated_rewards_by_reg_model=estimated_rewards_by_reg_model,
)
# store relative estimation errors of OPE estimators at each bootstrap
for (
estimator_name,
relative_estimation_error,
) in relative_estimation_errors.items():
relative_ee[estimator_name][b] = relative_estimation_error
print(
f"{b+1}th iteration: {np.round((time.time() - start) / 60, 2)}min")
