ray.rllib.callbacks.callbacks.RLlibCallback.on_evaluate_start#

RLlibCallback.on_evaluate_start(*, algorithm: Algorithm, metrics_logger: MetricsLogger | None = None, **kwargs) → None[source]#

Callback before evaluation starts.

This method gets called at the beginning of Algorithm.evaluate().

Parameters:

  • algorithm – Reference to the algorithm instance.

  • metrics_logger – The MetricsLogger object inside the Algorithm. Can be used to log custom metrics before running the next round of evaluation.

  • kwargs – Forward compatibility placeholder.