on_iteration_start

BaseCallback.on_iteration_start(iteration: int, params: ndarray, **kwargs) → None

Called at the start of each iteration.

Parameters:

iterationint

Current iteration number (1-indexed).

paramsnp.ndarray

Current parameter values.

**kwargs

Additional iteration-specific information. **kwargs is included for forward compatibility so adding new payload fields (e.g. an iteration timestamp) does not break every existing subclass.