TabPFN Classification Learner

Foundation model for tabular data. Uses reticulate to interface with the tabpfn Python package.

Installation

While the Python dependencies are handled via reticulate::py_require(), you can manually specify a virtual environment by calling reticulate::use_virtualenv() prior to calling the $train() function. In this virtual environment, the tabpfn package and its dependencies must be installed.

Saving a Learner

In order to save a LearnerClassifTabPFN for later usage, it is necessary to call the $marshal() method on the Learner before writing it to disk, as the object will otherwise not be saved correctly. After loading a marshaled LearnerClassifTabPFN into R again, you then need to call $unmarshal() to transform it into a useable state.

Initial parameter values

• n_jobs is initialized to 1 to avoid threading conflicts with future.

Custom mlr3 parameters

• categorical_feature_indices uses R indexing instead of zero-based Python indexing.

• device must be a string. If set to "auto", the behavior is the same as original. Otherwise, the string is passed as argument to torch.device() to create a device.

• inference_precision must be "auto" or "autocast". Passing torch.dtype is currently not supported.

• inference_config is currently not supported.

Dictionary

This Learner can be instantiated via lrn():

lrn("classif.tabpfn")

Meta Information

• Task type: “classif”

• Predict Types: “response”, “prob”

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

• Required Packages: mlr3

Parameters

Id	Type	Default	Levels	Range
n_estimators	integer	4		\([1, \infty)\)
categorical_features_indices	untyped	-		-
softmax_temperature	numeric	0.9		\([0, \infty)\)
balance_probabilities	logical	FALSE	TRUE, FALSE	-
average_before_softmax	logical	FALSE	TRUE, FALSE	-
model_path	untyped	"auto"		-
device	untyped	"auto"		-
ignore_pretraining_limits	logical	FALSE	TRUE, FALSE	-
inference_precision	character	auto	auto, autocast	-
fit_mode	character	fit_preprocessors	low_memory, fit_preprocessors, fit_with_cache	-
memory_saving_mode	untyped	"auto"		-
random_state	integer	0		\((-\infty, \infty)\)
n_jobs	integer	-		\([1, \infty)\)

References

Hollmann, Noah, Müller, Samuel, Purucker, Lennart, Krishnakumar, Arjun, Körfer, Max, Hoo, Bin S, Schirrmeister, Tibor R, Hutter, Frank (2025). “Accurate predictions on small data with a tabular foundation model.” Nature. doi:10.1038/s41586-024-08328-6 , https://www.nature.com/articles/s41586-024-08328-6.

Hollmann, Noah, Müller, Samuel, Eggensperger, Katharina, Hutter, Frank (2023). “TabPFN: A transformer that solves small tabular classification problems in a second.” In International Conference on Learning Representations 2023.

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

b-zhou

Super classes

mlr3::Learner -> mlr3::LearnerClassif -> LearnerClassifTabPFN

Active bindings

marshaled

(logical(1))
Whether the learner has been marshaled.

Methods

Public methods

• LearnerClassifTabPFN$new()

• LearnerClassifTabPFN$marshal()

• LearnerClassifTabPFN$unmarshal()

• LearnerClassifTabPFN$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()

---

Method new()

Creates a new instance of this R6 class.

Usage

LearnerClassifTabPFN$new()

---

Method marshal()

Marshal the learner's model.

Usage

LearnerClassifTabPFN$marshal(...)

Arguments

...

(any)
Additional arguments passed to marshal_model().

---

Method unmarshal()

Unmarshal the learner's model.

Usage

LearnerClassifTabPFN$unmarshal(...)

Arguments

...

(any)
Additional arguments passed to unmarshal_model().

---

Method clone()

The objects of this class are cloneable with this method.

Usage

LearnerClassifTabPFN$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Examples

# Define the Learner
learner = mlr3::lrn("classif.tabpfn")
print(learner)
#> <LearnerClassifTabPFN:classif.tabpfn>: TabPFN Classifier
#> * Model: -
#> * Parameters: n_jobs=1
#> * Packages: mlr3
#> * Predict Types:  [response], prob
#> * Feature Types: logical, integer, numeric
#> * Properties: marshal, missings, multiclass, twoclass

# Define a Task
task = mlr3::tsk("sonar")

# Create train and test set
ids = mlr3::partition(task)

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

print(learner$model)
#> $fitted
#> TabPFNClassifier(n_jobs=1)
#> 
#> attr(,"class")
#> [1] "tabpfn_model"


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

# Score the predictions
predictions$score()
#> classif.ce 
#>  0.1884058