# optuna.importance¶

The importance module provides functionality for evaluating hyperparameter importances based on completed trials in a given study. The utility function get_param_importances() takes a Study and optional evaluator as two of its inputs. The evaluator must derive from BaseImportanceEvaluator, and is initialized as a FanovaImportanceEvaluator by default when not passed in. Users implementing custom evaluators should refer to either FanovaImportanceEvaluator or MeanDecreaseImpurityImportanceEvaluator as a guide, paying close attention to the format of the return value from the Evaluator’s evaluate() function.

 optuna.importance.get_param_importances Evaluate parameter importances based on completed trials in the given study. optuna.importance.FanovaImportanceEvaluator fANOVA importance evaluator. optuna.importance.MeanDecreaseImpurityImportanceEvaluator Mean Decrease Impurity (MDI) parameter importance evaluator.