Linearly Transform Numeric Features to Match Given Boundaries
Source:R/PipeOpScaleRange.R
mlr_pipeops_scalerange.RdLinearly transforms numeric data columns so they are between lower
and upper. The formula for this is \(x' = offset + x * scale\),
where \(scale\) is \((upper - lower) / (max(x) - min(x))\) and
\(offset\) is \(-min(x) * scale + lower\). The same transformation is applied during training and
prediction.
Format
R6Class object inheriting from PipeOpTaskPreprocSimple/PipeOpTaskPreproc/PipeOp.
Construction
id::character(1)
Identifier of resulting object, default"scalerange".param_vals:: namedlist
List of hyperparameter settings, overwriting the hyperparameter settings that would otherwise be set during construction. Defaultlist().
Input and Output Channels
Input and output channels are inherited from PipeOpTaskPreproc.
The output is the input Task with scaled numeric features.
State
The $state is a named list with the $state elements inherited from PipeOpTaskPreproc,
as well as the two transformation parameters \(scale\) and \(offset\) for each numeric
feature.
Parameters
The parameters are the parameters inherited from PipeOpTaskPreproc, as well as:
lower::numeric(1)
Target value of smallest item of input data. Initialized to 0.upper::numeric(1)
Target value of greatest item of input data. Initialized to 1.
Methods
Only methods inherited from PipeOpTaskPreprocSimple/PipeOpTaskPreproc/PipeOp.
See also
https://mlr-org.com/pipeops.html
Other PipeOps:
PipeOp,
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_encode,
mlr_pipeops_encodeimpact,
mlr_pipeops_encodelmer,
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_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_threshold,
mlr_pipeops_tomek,
mlr_pipeops_tunethreshold,
mlr_pipeops_unbranch,
mlr_pipeops_updatetarget,
mlr_pipeops_vtreat,
mlr_pipeops_yeojohnson
Examples
library("mlr3")
task = tsk("iris")
pop = po("scalerange", param_vals = list(lower = -1, upper = 1))
task$data()
#> Species Petal.Length Petal.Width Sepal.Length Sepal.Width
#> <fctr> <num> <num> <num> <num>
#> 1: setosa 1.4 0.2 5.1 3.5
#> 2: setosa 1.4 0.2 4.9 3.0
#> 3: setosa 1.3 0.2 4.7 3.2
#> 4: setosa 1.5 0.2 4.6 3.1
#> 5: setosa 1.4 0.2 5.0 3.6
#> ---
#> 146: virginica 5.2 2.3 6.7 3.0
#> 147: virginica 5.0 1.9 6.3 2.5
#> 148: virginica 5.2 2.0 6.5 3.0
#> 149: virginica 5.4 2.3 6.2 3.4
#> 150: virginica 5.1 1.8 5.9 3.0
pop$train(list(task))[[1]]$data()
#> Species Petal.Length Petal.Width Sepal.Length Sepal.Width
#> <fctr> <num> <num> <num> <num>
#> 1: setosa -0.8644068 -0.9166667 -0.55555556 0.25000000
#> 2: setosa -0.8644068 -0.9166667 -0.66666667 -0.16666667
#> 3: setosa -0.8983051 -0.9166667 -0.77777778 0.00000000
#> 4: setosa -0.8305085 -0.9166667 -0.83333333 -0.08333333
#> 5: setosa -0.8644068 -0.9166667 -0.61111111 0.33333333
#> ---
#> 146: virginica 0.4237288 0.8333333 0.33333333 -0.16666667
#> 147: virginica 0.3559322 0.5000000 0.11111111 -0.58333333
#> 148: virginica 0.4237288 0.5833333 0.22222222 -0.16666667
#> 149: virginica 0.4915254 0.8333333 0.05555556 0.16666667
#> 150: virginica 0.3898305 0.4166667 -0.11111111 -0.16666667
pop$state
#> $Petal.Length
#> scale offset
#> 0.3389831 -1.3389831
#>
#> $Petal.Width
#> scale offset
#> 0.8333333 -1.0833333
#>
#> $Sepal.Length
#> scale offset
#> 0.5555556 -3.3888889
#>
#> $Sepal.Width
#> scale offset
#> 0.8333333 -2.6666667
#>
#> $dt_columns
#> [1] "Petal.Length" "Petal.Width" "Sepal.Length" "Sepal.Width"
#>
#> $affected_cols
#> [1] "Petal.Length" "Petal.Width" "Sepal.Length" "Sepal.Width"
#>
#> $intasklayout
#> Key: <id>
#> id type
#> <char> <char>
#> 1: Petal.Length numeric
#> 2: Petal.Width numeric
#> 3: Sepal.Length numeric
#> 4: Sepal.Width numeric
#>
#> $outtasklayout
#> Key: <id>
#> id type
#> <char> <char>
#> 1: Petal.Length numeric
#> 2: Petal.Width numeric
#> 3: Sepal.Length numeric
#> 4: Sepal.Width numeric
#>
#> $outtaskshell
#> Empty data.table (0 rows and 5 cols): Species,Petal.Length,Petal.Width,Sepal.Length,Sepal.Width
#>