`mtry` in R language `ranger`

Question

Which of the following understanding is true?

• The number of features that we can use per tree (we bootstrap a subset of features)
• The number of features that we use for each split

With equivalent function RandomForestClassifier.max_features in Python package scikit-learn, the first understanding is true. What is the situation in R language?

Thank you!

Answer 1

mtry in ranger and randomForest is the number of features, randomly sampled, to split at each node.