Try a longer tune length
Recall from the video that random forest models have a primary tuning parameter of mtry, which controls how many variables are exposed to the splitting search routine at each split. For example, suppose that a tree has a total of 10 splits and mtry = 2. This means that there are 10 samples of 2 predictors each time a split is evaluated.
Use a larger tuning grid this time, but stick to the defaults provided by the train() function. Try a tuneLength of 3, rather than 1, to explore some more potential models, and plot the resulting model using the plot function.
Это упражнение является частью курса
Machine Learning with caret in R
Инструкции к упражнению
- Train a random forest model,
model, using thewinedataset on thequalityvariable with all other variables as explanatory variables. (This will take a few seconds to run, so be patient!) - Use
method = "ranger". - Change the
tuneLengthto 3. - Use 5 CV folds.
- Print
modelto the console. - Plot the model after fitting it.
Интерактивное практическое упражнение
Попробуйте выполнить это упражнение, дополнив этот пример кода.
# Fit random forest: model
model <- train(
___,
tuneLength = 1,
data = ___,
method = ___,
trControl = trainControl(
method = "cv",
number = ___,
verboseIter = TRUE
)
)
# Print model to console
# Plot model