Introduction

The tisthemachinelearner package provides a simple R interface to scikit-learn models through Python’s tisthemachinelearner package. This vignette demonstrates how to use the package with R’s built-in mtcars dataset.

Setup

First, let’s load the required packages:

library(tisthemachinelearner)
library(reticulate)

Data Preparation

We’ll use the classic mtcars dataset to predict miles per gallon (mpg) based on other car characteristics:

# Load data

# Split features and target
X <- as.matrix(MASS::Boston[, -14])  # all columns except mpg
y <- MASS::Boston[, 14]              # mpg column

# Create train/test split
set.seed(42)
train_idx <- sample(nrow(X), size = floor(0.8 * nrow(X)))
X_train <- X[train_idx, ]
X_test <- X[-train_idx, ]
y_train <- y[train_idx]
y_test <- y[-train_idx]

Ridge Regression with Cross-Validation

Now let’s try Ridge regression with cross-validation for hyperparameter tuning:

# Fit ridge regression model
reg_ridge <- tisthemachinelearner::regressor(X_train, y_train, "Ridge", 
                      #alphas = c(0.01, 0.1, 1, 10),
                      calibration = TRUE)

# Make predictions
predictions_ridge_splitconformal <- predict(reg_ridge, X_test, method = "splitconformal")
predictions_ridge_surrogate <- predict(reg_ridge, X_test, method = "surrogate")
#> Registered S3 method overwritten by 'quantmod':
#>   method            from
#>   as.zoo.data.frame zoo
predictions_ridge_bootstrap <- predict(reg_ridge, X_test, method = "bootstrap")

# Calculate coverage
coverage_ridge_splitconformal <- mean(y_test >= predictions_ridge_splitconformal[, "lwr"] & y_test <= predictions_ridge_splitconformal[, "upr"])
coverage_ridge_surrogate <- mean(y_test >= predictions_ridge_surrogate[, "lwr"] & y_test <= predictions_ridge_surrogate[, "upr"])
coverage_ridge_bootstrap <- mean(y_test >= predictions_ridge_bootstrap[, "lwr"] & y_test <= predictions_ridge_bootstrap[, "upr"])

cat("Ridge Regression Split Conformal Coverage:", coverage_ridge_splitconformal, "\n")
#> Ridge Regression Split Conformal Coverage: 0.9411765
cat("Ridge Regression Surrogate Coverage:", coverage_ridge_surrogate, "\n")
#> Ridge Regression Surrogate Coverage: 0.8921569
cat("Ridge Regression Bootstrap Coverage:", coverage_ridge_bootstrap, "\n")
#> Ridge Regression Bootstrap Coverage: 0.9117647

Session Info

sessionInfo()
#> R version 4.3.3 (2024-02-29)
#> Platform: x86_64-apple-darwin20 (64-bit)
#> Running under: macOS Sonoma 14.2
#> 
#> Matrix products: default
#> BLAS:   /Library/Frameworks/R.framework/Versions/4.3-x86_64/Resources/lib/libRblas.0.dylib 
#> LAPACK: /Library/Frameworks/R.framework/Versions/4.3-x86_64/Resources/lib/libRlapack.dylib;  LAPACK version 3.11.0
#> 
#> locale:
#> [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
#> 
#> time zone: Europe/Paris
#> tzcode source: internal
#> 
#> attached base packages:
#> [1] stats     graphics  grDevices utils     datasets  methods   base     
#> 
#> other attached packages:
#> [1] reticulate_1.41.0          tisthemachinelearner_0.3.1
#> 
#> loaded via a namespace (and not attached):
#>  [1] cli_3.6.4         knitr_1.49        rlang_1.1.5       xfun_0.50        
#>  [5] png_0.1-8         textshaping_1.0.0 jsonlite_1.9.0    zoo_1.8-12       
#>  [9] TTR_0.24.4        xts_0.14.1        htmltools_0.5.8.1 ragg_1.3.3       
#> [13] sass_0.4.9        rmarkdown_2.29    quadprog_1.5-8    grid_4.3.3       
#> [17] evaluate_1.0.3    jquerylib_0.1.4   MASS_7.3-60.0.1   fastmap_1.2.0    
#> [21] yaml_2.3.10       lifecycle_1.0.4   compiler_4.3.3    fs_1.6.5         
#> [25] Rcpp_1.0.14       htmlwidgets_1.6.4 systemfonts_1.1.0 lattice_0.22-5   
#> [29] digest_0.6.37     R6_2.6.1          curl_6.2.0        quantmod_0.4.26  
#> [33] bslib_0.9.0       Matrix_1.6-5      tools_4.3.3       tseries_0.10-58  
#> [37] pkgdown_2.1.1     cachem_1.1.0      desc_1.4.3