Linearly transforms numeric data columns so they are between lower and upper. The formula for this is \(x' = a + x * b\), where \(b\) is \((upper - lower) / (max(x) - min(x))\) and \(a\) is \(-min(x) * b + lower\).

Format

R6Class object inheriting from PipeOpTaskPreprocSimple/PipeOpTaskPreproc/PipeOp.

Construction

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

  • 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

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 \(a\) and \(b\) 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. Default is 0.

  • upper :: numeric(1)
    Target value of greatest item of input data. Default is 1.

Methods

Only methods inherited from PipeOpTaskPreprocSimple/PipeOpTaskPreproc/PipeOp.

See also

Examples

library("mlr3") task = tsk("iris") pop = po("scalerange", param_vals = list(lower = -1, upper = 1)) task$data()
#> Species Petal.Length Petal.Width Sepal.Length Sepal.Width #> 1: setosa 1.4 0.2 5.1 3.5 #> 2: setosa 1.4 0.2 4.9 3.0 #> 3: setosa 1.3 0.2 4.7 3.2 #> 4: setosa 1.5 0.2 4.6 3.1 #> 5: setosa 1.4 0.2 5.0 3.6 #> --- #> 146: virginica 5.2 2.3 6.7 3.0 #> 147: virginica 5.0 1.9 6.3 2.5 #> 148: virginica 5.2 2.0 6.5 3.0 #> 149: virginica 5.4 2.3 6.2 3.4 #> 150: virginica 5.1 1.8 5.9 3.0
pop$train(list(task))[[1]]$data()
#> Species Petal.Length Petal.Width Sepal.Length Sepal.Width #> 1: setosa -0.8644068 -0.9166667 -0.55555556 0.25000000 #> 2: setosa -0.8644068 -0.9166667 -0.66666667 -0.16666667 #> 3: setosa -0.8983051 -0.9166667 -0.77777778 0.00000000 #> 4: setosa -0.8305085 -0.9166667 -0.83333333 -0.08333333 #> 5: setosa -0.8644068 -0.9166667 -0.61111111 0.33333333 #> --- #> 146: virginica 0.4237288 0.8333333 0.33333333 -0.16666667 #> 147: virginica 0.3559322 0.5000000 0.11111111 -0.58333333 #> 148: virginica 0.4237288 0.5833333 0.22222222 -0.16666667 #> 149: virginica 0.4915254 0.8333333 0.05555556 0.16666667 #> 150: virginica 0.3898305 0.4166667 -0.11111111 -0.16666667
pop$state
#> $Petal.Length #> [1] -1.3389831 0.3389831 #> #> $Petal.Width #> [1] -1.0833333 0.8333333 #> #> $Sepal.Length #> [1] -3.3888889 0.5555556 #> #> $Sepal.Width #> [1] -2.6666667 0.8333333 #> #> $dt_columns #> [1] "Petal.Length" "Petal.Width" "Sepal.Length" "Sepal.Width" #> #> $affected_cols #> [1] "Petal.Length" "Petal.Width" "Sepal.Length" "Sepal.Width" #> #> $intasklayout #> id type #> 1: Petal.Length numeric #> 2: Petal.Width numeric #> 3: Sepal.Length numeric #> 4: Sepal.Width numeric #> #> $outtasklayout #> id type #> 1: Petal.Length numeric #> 2: Petal.Width numeric #> 3: Sepal.Length numeric #> 4: Sepal.Width numeric #>