This feature is to annotate experiments with user-defined attributes.
A :class:`~optuna.study.Study` object provides :func:`~optuna.study.Study.set_user_attr` method to
register a pair of key and value as an user-defined attribute.
A key is supposed to be a str
, and a value be any object serializable with json.dumps
.
import optuna
study = optuna.create_study(storage='sqlite:///example.db')
study.set_user_attr('contributors', ['Akiba', 'Sano'])
study.set_user_attr('dataset', 'MNIST')
We can access annotated attributes with :attr:`~optuna.study.Study.user_attr` property.
study.user_attrs # {'contributors': ['Akiba', 'Sano'], 'dataset': 'MNIST'}
:class:`~optuna.struct.StudySummary` object, which can be retrieved by :func:`~optuna.study.get_all_study_summaries`, also contains user-defined attributes.
study_summaries = optuna.get_all_study_summaries('sqlite:///example.db')
study_summaries[0].user_attrs # {'contributors': ['Akiba', 'Sano'], 'dataset': 'MNIST'}
.. seealso:: ``optuna study set-user-attr`` command, which sets an attribute via command line interface.
As with :class:`~optuna.study.Study`, a :class:`~optuna.trial.Trial` object provides :func:`~optuna.trial.Trial.set_user_attr` method. Attributes are set inside an objective function.
def objective(trial):
iris = sklearn.datasets.load_iris()
x, y = iris.data, iris.target
svc_c = trial.suggest_loguniform('svc_c', 1e-10, 1e10)
clf = sklearn.svm.SVC(C=svc_c)
accuracy = sklearn.model_selection.cross_val_score(clf, x, y).mean()
trial.set_user_attr('accuracy', accuracy)
return 1.0 - accuracy # return error for minimization
We can access annotated attributes as:
study.trials[0].user_attrs # {'accuracy': 0.83}
Note that, in this example, the attribute is not annotated to a :class:`~optuna.study.Study` but a single :class:`~optuna.trial.Trial`.