Abstract Terminator class that implements the base functionality each terminator must provide. A terminator is an object that determines when to stop the tuning.

Termination of tuning works as follows:

• Evaluations in a tuner are performed in batches.

• Before each batch evaluation, the Terminator is checked, and if it is positive, we stop.

• The tuning algorithm itself might decide not to produce any more points, or even might decide to do a smaller batch in its last evaluation.

Therefore the following note seems in order: While it is definitely possible to execute a fine-grained control for termination, and for many tuners we can specify exactly when to stop, it might happen that too few or even too many evaluations are performed, especially if multiple points are evaluated in a single batch (c.f. batch size parameter of many tuners). So it is advised to check the size of the returned archive, in particular if you are benchmarking multiple tuners.

## Format

R6::R6Class object.

## Construction

t = Terminator$new(param_set = ParamSet$new())

• param_set :: paradox::ParamSet
Set of control parameters for terminator.

## Methods

• is_terminated(instance)
TuningInstance -> logical(1)
Is TRUE iff the termination criterion is positive, and FALSE otherwise. Must be implemented in each subclass.

Other Terminator: mlr_terminators_clock_time, mlr_terminators_combo, mlr_terminators_evals, mlr_terminators_model_time, mlr_terminators_none, mlr_terminators_perf_reached, mlr_terminators_stagnation, mlr_terminators