Splits a classification Task into several binary classification Tasks to perform "One vs. Rest" classification. This works in combination with PipeOpOVRUnite.

For each target level a new binary classification Task is constructed with the respective target level being the positive class and all other target levels being the new negative class "rest".

This PipeOp creates a Multiplicity, which means that subsequent PipeOps are executed multiple times, once for each created binary Task, until a PipeOpOVRUnite is reached.

Note that Multiplicity is currently an experimental features and the implementation or UI may change.


R6Class inheriting from PipeOp.


PipeOpOVRSplit$new(id = "ovrsplit", param_vals = list())
  • id :: character(1) Identifier of the resulting object, default "ovrsplit".

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

Input and Output Channels

PipeOpOVRSplit has one input channel named "input" taking a TaskClassif both during training and prediction.

PipeOpOVRSplit has one output channel named "output" returning a Multiplicity of TaskClassifs both during training and prediction, i.e., the newly constructed binary classification Tasks.


The $state contains the original target levels of the TaskClassif supplied during training.


PipeOpOVRSplit has no parameters.


The original target levels stored in the $state are also used during prediction when creating the new binary classification Tasks.

The names of the element of the output Multiplicity are given by the levels of the target.

If a target level "rest" is present in the input TaskClassif, the negative class will be labeled as "rest." (using as many "."` postfixes needed to yield a valid label).

Should be used in combination with PipeOpOVRUnite.


Only fields inherited from PipeOp.


Only methods inherited from PipeOp.

See Also

Other PipeOps: PipeOpEnsemble, PipeOpImpute, PipeOpTargetTrafo, PipeOpTaskPreprocSimple, PipeOpTaskPreproc, PipeOp, 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_encodeimpact, mlr_pipeops_encodelmer, mlr_pipeops_encode, 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_missind, mlr_pipeops_modelmatrix, mlr_pipeops_multiplicityexply, mlr_pipeops_multiplicityimply, mlr_pipeops_mutate, mlr_pipeops_nmf, mlr_pipeops_nop, 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_scalemaxabs, mlr_pipeops_scalerange, mlr_pipeops_scale, mlr_pipeops_select, mlr_pipeops_smote, mlr_pipeops_spatialsign, mlr_pipeops_subsample, mlr_pipeops_targetinvert, mlr_pipeops_targetmutate, mlr_pipeops_targettrafoscalerange, mlr_pipeops_textvectorizer, mlr_pipeops_threshold, mlr_pipeops_tunethreshold, mlr_pipeops_unbranch, mlr_pipeops_updatetarget, mlr_pipeops_vtreat, mlr_pipeops_yeojohnson, mlr_pipeops

Other Multiplicity PipeOps: Multiplicity(), PipeOpEnsemble, mlr_pipeops_classifavg, mlr_pipeops_featureunion, mlr_pipeops_multiplicityexply, mlr_pipeops_multiplicityimply, mlr_pipeops_ovrunite, mlr_pipeops_regravg, mlr_pipeops_replicate

Other Experimental Features: Multiplicity(), mlr_pipeops_multiplicityexply, mlr_pipeops_multiplicityimply, mlr_pipeops_ovrunite, mlr_pipeops_replicate

  • mlr_pipeops_ovrsplit
  • PipeOpOVRSplit
task = tsk("iris")
po = po("ovrsplit")
# }
Documentation reproduced from package mlr3pipelines, version 0.3.0, License: LGPL-3

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