Generates a more balanced data set by creating synthetic instances of the minority class using the SMOTE algorithm. The algorithm samples for each minority instance a new data point based on the K nearest neighbors of that data point. It can only be applied to tasks with numeric features. See smotefamily::SMOTE for details.


R6Class object inheriting from PipeOpTaskPreproc/PipeOp.


PipeOpSmote$new(id = "smote", param_vals = list())

Identifier of resulting object, default "smote".

  • 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 during training is the input Task with added synthetic rows for the minority class. The output during prediction is the unchanged input.


The $state is a named list with the $state elements inherited from PipeOpTaskPreproc.


The parameters are the parameters inherited from PipeOpTaskPreproc, as well as:

  • K :: numeric(1)
    The number of nearest neighbors used for sampling new values. See SMOTE().

  • dup_size :: numeric
    Desired times of synthetic minority instances over the original number of majority instances. See SMOTE().


For details see:
Chawla, N., Bowyer, K., Hall, L. and Kegelmeyer, W. 2002.
SMOTE: Synthetic minority oversampling technique.
Journal of Artificial Intelligence Research. 16, 321-357.


Only fields inherited from PipeOpTaskPreproc/PipeOp.


Only methods inherited from PipeOpTaskPreproc/PipeOp.

See also


library("mlr3") # Create example task data_example = smotefamily::sample_generator(1000, ratio = 0.80)
#> Error in loadNamespace(name): there is no package called ‘smotefamily’
task = TaskClassif$new(id = "example", backend = data_example, target = "result")
#> Error in inherits(backend, "DataBackend"): object 'data_example' not found
#> Error in eval(expr, envir, enclos): object 'task' not found
#> Error in table(task$data()$result): object 'task' not found
# Generate synthetic data for minority class pop = po("smote") smotedata = pop$train(list(task))[[1]]$data()
#> Error: The following packages could not be loaded: smotefamily
#> Error in table(smotedata$result): object 'smotedata' not found