Classification Random Planted Forest Learner

Random Planted Forest: A directly interpretable tree ensemble.

Calls randomPlantedForest::rpf() from 'randomPlantedForest'.

Initial parameter values

• loss:

  • Actual default: "L2".

  • Initial value: "exponential".

  • Reason for change: Using "L2" (or "L1") loss does not guarantee predictions are valid probabilities and more akin to the linear predictor of a GLM.

Custom mlr3 parameters

• max_interaction:

  • This hyperparameter can alternatively be set via max_interaction_ratio as max_interaction = max(ceiling(max_interaction_ratio * n_features), 1). The parameter max_interaction_limit can optionally be set as an upper bound, such that max_interaction_ratio * min(n_features, max_interaction_limit) is used instead. This is analogous to mtry.ratio in classif.ranger, with max_interaction_limit as an additional constraint. The parameter max_interaction_limit is initialized to Inf.

Dictionary

This Learner can be instantiated via lrn():

lrn("classif.rpf")

Meta Information

• Task type: “classif”

• Predict Types: “response”, “prob”

• Feature Types: “logical”, “integer”, “numeric”, “factor”, “ordered”

• Required Packages: mlr3, randomPlantedForest

Parameters

Id	Type	Default	Levels	Range
max_interaction	integer	1		\([0, \infty)\)
max_interaction_ratio	numeric	-		\([0, 1]\)
max_interaction_limit	integer	-		\([1, \infty)\)
ntrees	integer	50		\([1, \infty)\)
splits	integer	30		\([1, \infty)\)
split_try	integer	10		\([1, \infty)\)
t_try	numeric	0.4		\([0, 1]\)
loss	character	L2	L1, L2, logit, exponential	-
delta	numeric	1		\([0, 1]\)
epsilon	numeric	0.1		\([0, 1]\)
deterministic	logical	FALSE	TRUE, FALSE	-
nthreads	integer	1		\([1, \infty)\)
cv	logical	FALSE	TRUE, FALSE	-
purify	logical	FALSE	TRUE, FALSE	-

Installation

Package 'randomPlantedForest' is not on CRAN and has to be installed from GitHub via remotes::install_github("PlantedML/randomPlantedForest").

References

Hiabu, Munir, Mammen, Enno, Meyer, T. J (2023). “Random Planted Forest: a directly interpretable tree ensemble.” arXiv preprint arXiv:2012.14563. doi:10.48550/ARXIV.2012.14563 .

See also

• Dictionary of Learners: mlr3::mlr_learners.

• as.data.table(mlr_learners) for a table of available Learners in the running session (depending on the loaded packages).

• Chapter in the mlr3book: https://mlr3book.mlr-org.com/basics.html#learners

• mlr3learners for a selection of recommended learners.

• mlr3cluster for unsupervised clustering learners.

• mlr3pipelines to combine learners with pre- and postprocessing steps.

• mlr3tuning for tuning of hyperparameters, mlr3tuningspaces for established default tuning spaces.

Author

jemus42

Super classes

mlr3::Learner -> mlr3::LearnerClassif -> LearnerClassifRandomPlantedForest

Methods

Public methods

• LearnerClassifRandomPlantedForest$new()

• LearnerClassifRandomPlantedForest$clone()

Inherited methods

• mlr3::Learner$base_learner()
• mlr3::Learner$configure()
• mlr3::Learner$encapsulate()
• mlr3::Learner$format()
• mlr3::Learner$help()
• mlr3::Learner$predict()
• mlr3::Learner$predict_newdata()
• mlr3::Learner$print()
• mlr3::Learner$reset()
• mlr3::Learner$selected_features()
• mlr3::Learner$train()
• mlr3::LearnerClassif$predict_newdata_fast()

---

Method new()

Creates a new instance of this R6 class.

Usage

LearnerClassifRandomPlantedForest$new()

---

Method clone()

The objects of this class are cloneable with this method.

Usage

LearnerClassifRandomPlantedForest$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Examples

# Define the Learner
learner = lrn("classif.rpf")
print(learner)
#> 
#> ── <LearnerClassifRandomPlantedForest> (classif.rpf): Random Planted Forest ────
#> • Model: -
#> • Parameters: max_interaction_limit=Inf, loss=exponential
#> • Packages: mlr3 and randomPlantedForest
#> • Predict Types: [response] and prob
#> • Feature Types: logical, integer, numeric, factor, and ordered
#> • Encapsulation: none (fallback: -)
#> • Properties: multiclass and twoclass
#> • Other settings: use_weights = 'error'

# Define a Task
task = tsk("sonar")

# Create train and test set
ids = partition(task)

# Train the learner on the training ids
learner$train(task, row_ids = ids$train)

print(learner$model)
#> -- Classification Random Planted Forest --
#> 
#> Formula: NULL 
#> Fit using 60 predictors and main effects only.
#> Forest is _not_ purified!
#> 
#> Called with parameters:
#> 
#>             loss: exponential
#>           ntrees: 50
#>  max_interaction: 1
#>           splits: 30
#>        split_try: 10
#>            t_try: 0.4
#>            delta: 0
#>          epsilon: 0.1
#>    deterministic: FALSE
#>         nthreads: 1
#>           purify: FALSE
#>               cv: FALSE


# Make predictions for the test rows
predictions = learner$predict(task, row_ids = ids$test)

# Score the predictions
predictions$score()
#> classif.ce 
#>  0.2753623