mlr_pipeops_threshold: Change the Threshold of a Classification Prediction

In mlr3pipelines: Preprocessing Operators and Pipelines for 'mlr3'

Change the Threshold of a Classification Prediction

Description

Change the threshold of a Prediction during the predict step. The incoming Learner's ⁠$predict_type⁠ needs to be "prob". Internally calls PredictionClassif$set_threshold.

Format

R6Class inheriting from PipeOp.

Construction

PipeOpThreshold$new(id = "threshold", param_vals = list())

• id :: character(1) Identifier of the resulting object, default "threshold".

• param_vals :: named list
  List of hyperparameter settings, overwriting the hyperparameter settings that would otherwise be set during construction. Defaults to numeric(0).

Input and Output Channels

During training, the input and output are NULL. A PredictionClassif is required as input and returned as output during prediction.

State

The ⁠$state⁠ is left empty (list()).

Parameters

• thresholds :: numeric
  A numeric vector of thresholds for the different class levels. May have length 1 for binary classification predictions, must otherwise have length of the number of target classes; see PredictionClassif's ⁠$set_threshold()⁠ method. Initialized to 0.5, i.e. thresholding for binary classification at level 0.5.

Fields

Fields inherited from PipeOp, as well as:

• predict_type :: character(1)
  Type of prediction to return. Either "prob" (default) or "response". Setting to "response" should rarely be used; it may potentially save some memory but has no other benefits.

Methods

Only methods inherited from PipeOp.

See Also

https://mlr-org.com/pipeops.html

Other PipeOps: PipeOp, PipeOpEncodePL, PipeOpEnsemble, PipeOpImpute, PipeOpTargetTrafo, PipeOpTaskPreproc, PipeOpTaskPreprocSimple, mlr_pipeops, mlr_pipeops_adas, mlr_pipeops_blsmote, mlr_pipeops_boxcox, mlr_pipeops_branch, mlr_pipeops_chunk, mlr_pipeops_classbalancing, mlr_pipeops_classifavg, mlr_pipeops_classweights, mlr_pipeops_colapply, mlr_pipeops_collapsefactors, mlr_pipeops_colroles, mlr_pipeops_copy, mlr_pipeops_datefeatures, mlr_pipeops_decode, mlr_pipeops_encode, mlr_pipeops_encodeimpact, mlr_pipeops_encodelmer, mlr_pipeops_encodeplquantiles, mlr_pipeops_encodepltree, mlr_pipeops_featureunion, mlr_pipeops_filter, mlr_pipeops_fixfactors, mlr_pipeops_histbin, mlr_pipeops_ica, mlr_pipeops_imputeconstant, mlr_pipeops_imputehist, mlr_pipeops_imputelearner, mlr_pipeops_imputemean, mlr_pipeops_imputemedian, mlr_pipeops_imputemode, mlr_pipeops_imputeoor, mlr_pipeops_imputesample, mlr_pipeops_kernelpca, mlr_pipeops_learner, mlr_pipeops_learner_pi_cvplus, mlr_pipeops_learner_quantiles, mlr_pipeops_missind, mlr_pipeops_modelmatrix, mlr_pipeops_multiplicityexply, mlr_pipeops_multiplicityimply, mlr_pipeops_mutate, mlr_pipeops_nearmiss, mlr_pipeops_nmf, mlr_pipeops_nop, mlr_pipeops_ovrsplit, mlr_pipeops_ovrunite, mlr_pipeops_pca, mlr_pipeops_proxy, mlr_pipeops_quantilebin, mlr_pipeops_randomprojection, mlr_pipeops_randomresponse, mlr_pipeops_regravg, mlr_pipeops_removeconstants, mlr_pipeops_renamecolumns, mlr_pipeops_replicate, mlr_pipeops_rowapply, mlr_pipeops_scale, mlr_pipeops_scalemaxabs, mlr_pipeops_scalerange, mlr_pipeops_select, mlr_pipeops_smote, mlr_pipeops_smotenc, mlr_pipeops_spatialsign, mlr_pipeops_subsample, mlr_pipeops_targetinvert, mlr_pipeops_targetmutate, mlr_pipeops_targettrafoscalerange, mlr_pipeops_textvectorizer, mlr_pipeops_tomek, mlr_pipeops_tunethreshold, mlr_pipeops_unbranch, mlr_pipeops_updatetarget, mlr_pipeops_vtreat, mlr_pipeops_yeojohnson

Examples

library("mlr3")
t = tsk("german_credit")
gr = po(lrn("classif.rpart", predict_type = "prob")) %>>%
  po("threshold", param_vals = list(thresholds = 0.9))
gr$train(t)
gr$predict(t)

mlr3pipelines documentation built on Aug. 8, 2025, 7:19 p.m.