microsoft/qlib · error · NotImplementedError

Please implement the `delete_exp` method.

Error message

Please implement the `delete_exp` method.

What it means

ExpManager.delete_exp is abstract: concrete managers delete the experiment identified by experiment_id or experiment_name. The base stub raises NotImplementedError, meaning no backend (normally MLflowExpManager, which calls client.delete_experiment) executed the deletion.

Source

Thrown at qlib/workflow/expm.py:280

        Raises
        ------
        ValueError
        """
        raise NotImplementedError(f"Please implement the `_get_exp` method")

    def delete_exp(self, experiment_id=None, experiment_name=None):
        """
        Delete an experiment.

        Parameters
        ----------
        experiment_id  : str
            the experiment id.
        experiment_name  : str
            the experiment name.
        """
        raise NotImplementedError(f"Please implement the `delete_exp` method.")

    @property
    def default_uri(self):
        """
        Get the default tracking URI from qlib.config.C
        """
        if "kwargs" not in C.exp_manager or "uri" not in C.exp_manager["kwargs"]:
            raise ValueError("The default URI is not set in qlib.config.C")
        return C.exp_manager["kwargs"]["uri"]

    @default_uri.setter
    def default_uri(self, value):
        C.exp_manager.setdefault("kwargs", {})["uri"] = value

    @property
    def uri(self):
        """
        Get the default tracking URI or current URI.

View on GitHub (pinned to 79633dd950)

Solutions

1. Restore the default MLflowExpManager so deletion reaches MLflow's delete_experiment.
2. Implement delete_exp(self, experiment_id=None, experiment_name=None) in your subclass.
3. Or delete directly through the backend API (mlflow.tracking.MlflowClient.delete_experiment) as a stopgap.

Example fix

# before
ExpManager().delete_exp(experiment_name='old')  # NotImplementedError

# after
R.delete_exp(experiment_name='old')  # with default MLflowExpManager

from qlib.workflow.expm import ExpManager
assert R.exp_manager.__class__.delete_exp is not ExpManager.delete_exp, 'deletion unsupported'

def manager_can_delete(mgr) -> bool:
    from qlib.workflow.expm import ExpManager
    return mgr.__class__.delete_exp is not ExpManager.delete_exp

When it happens

Trigger: R.delete_exp(experiment_name='x') or exp_manager.delete_exp(...) where the configured manager class is the base or an incomplete subclass.

Common situations: Housekeeping scripts pruning old experiments while a custom manager backend is configured; subclass implementations that cover listing but not deletion.

Related errors

• Please implement the `delete_recorder` method.
• Please implement the `start_exp` method.
• Please implement the `end_exp` method.
• Please implement the `create_exp` method.
• Please implement the `search_records` method.

AI-assisted analysis of microsoft/qlib@79633dd950 (2026-08-15). Data as JSON: /api/errors/25697dc2b96b4788. Report an issue: GitHub.