Update Human-in-the-loop example

examples/hitl/main.py

@@ -1,5 +1,6 @@
 import os
 import textwrap
+import time
 from typing import NoReturn
 
 import optuna
@@ -7,7 +8,6 @@ from optuna.trial import TrialState
 from optuna_dashboard import ChoiceWidget
 from optuna_dashboard import register_objective_form_widgets
 from optuna_dashboard import save_note
-from optuna_dashboard import set_objective_names
 from optuna_dashboard.artifact import get_artifact_path
 from optuna_dashboard.artifact import upload_artifact
 from optuna_dashboard.artifact.file_system import FileSystemBackend
@@ -41,20 +41,17 @@ def suggest_and_generate_image(study: optuna.Study, artifact_backend: FileSystem
     save_note(trial, note)
 
 
-def start_optimization(
-    storage: optuna.storages.BaseStorage, artifact_backend: FileSystemBackend
-) -> NoReturn:
+def start_optimization(artifact_backend: FileSystemBackend) -> NoReturn:
     # 1. Create Study
-    sampler = optuna.samplers.TPESampler(constant_liar=True)
     study = optuna.create_study(
         study_name="Human-in-the-loop Optimization",
-        storage=storage,
-        sampler=sampler,
+        storage="sqlite:///db.sqlite3",
+        sampler=optuna.samplers.TPESampler(constant_liar=True, n_startup_trials=5),
         load_if_exists=True,
     )
 
     # 2. Set an objective name
-    set_objective_names(study, ["Looks like sunset color?"])
+    study.set_metric_names(["Looks like sunset color?"])
 
     # 3. Register ChoiceWidget
     register_objective_form_widgets(
@@ -73,6 +70,7 @@ def start_optimization(
     while True:
         running_trials = study.get_trials(deepcopy=False, states=(TrialState.RUNNING,))
         if len(running_trials) >= n_batch:
+            time.sleep(1)  # Avoid busy-loop
             continue
         suggest_and_generate_image(study, artifact_backend)
 
@@ -80,11 +78,7 @@ def start_optimization(
 def main() -> NoReturn:
     tmp_path = os.path.join(os.path.dirname(__file__), "tmp")
 
-    # 1. Create RDBStorage
-    url = "sqlite:///db.sqlite3"
-    storage = optuna.storages.RDBStorage(url=url)
-
-    # 2. Create Artifact Storage
+    # 1. Create Artifact Store
     artifact_path = os.path.join(os.path.dirname(__file__), "artifact")
     artifact_backend = FileSystemBackend(base_path=artifact_path)
 
@@ -94,8 +88,8 @@ def main() -> NoReturn:
     if not os.path.exists(tmp_path):
         os.mkdir(tmp_path)
 
-    # 3. Run optimize loop
-    start_optimization(storage, artifact_backend)
+    # 2. Run optimize loop
+    start_optimization(artifact_backend)
 
 
 if __name__ == "__main__":