Class PatientPruner

Namespace

OptunaSharp.Pruners

Assembly

OptunaSharp.dll

Pruner which wraps another pruner with tolerance. Port of optuna/pruners/_patient.py: PatientPruner (experimental since 2.8.0).

This pruner monitors intermediate values in a trial and prunes the trial if the improvement in the intermediate values after a patience period is less than a threshold.

The pruner handles NaN values in the following manner:

1. If all intermediate values before or during the patient period are NaN, the trial will not be pruned.
2. During the pruning calculations, NaN values are ignored. Only valid numeric values are considered.

public class PatientPruner : BasePruner

Inheritance

object

BasePruner

PatientPruner

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Constructors

PatientPruner(BasePruner?, int, double)

Configures the report-history tolerance required before allowing a wrapped pruning decision.

public PatientPruner(BasePruner? wrappedPruner, int patience, double minDelta = 0)

Parameters

wrappedPruner BasePruner

Wrapped pruner to perform pruning when PatientPruner allows a trial to be pruned. If it is null, this pruner is equivalent to early-stopping taken the intermediate values in the individual trial.

patience int

Pruning is disabled until the objective doesn't improve for patience consecutive steps.

minDelta double

Tolerance value to check whether or not the objective improves. Must be non-negative.

Exceptions

ValueError

Patience or the minimum improvement tolerance is negative.

Methods

Prune(Study, FrozenTrial)

Judge whether the trial should be pruned based on the reported values.

Note that this method is not supposed to be called by library users. Instead, Report(double, long) and ShouldPrune() provide user interfaces to implement pruning mechanism in an objective function.

public override bool Prune(Study study, FrozenTrial trial)

Parameters

study Study

Study object of the target study.

trial FrozenTrial

FrozenTrial object of the target trial. Take a copy before modifying this object.

Returns

bool

A boolean value representing whether the trial should be pruned.

Exceptions

RuntimeError

The study has multiple objectives and the pruning rule requests its scalar direction.

Exception

The wrapped pruner fails; its exception propagates once the patience rule permits pruning.

See Also

Official Optuna PatientPruner reference.