Factory for learner wrappers
Create custom learners and/or a sequence of learners with hyperparameter combinations defined over a grid.
create.Learner(base_learner, params = list(), tune = list(), env = parent.frame(), name_prefix = base_learner, detailed_names = F, verbose = F)
base_learner |
Character string of the learner function that will be customized. |
params |
List with parameters to customize. |
tune |
List of hyperparameter settings that will define custom learners. |
env |
Environment in which to create the functions. Defaults to the current environment (e.g. often the global environment). |
name_prefix |
The prefix string for the name of each function that is generated. |
detailed_names |
Set to T to have the function names include the parameter configurations. |
verbose |
Display extra details. |
Returns a list with expanded tuneGrid and the names of the created functions.
## Not run:
# Create a randomForest learner with ntree set to 1000 rather than the
# default of 500.
create_rf = create.Learner("SL.randomForest", list(ntree = 1000))
create_rf
sl = SuperLearner(Y = Y, X = X, SL.library = create_rf$names, family = binomial())
sl
# Clean up global environment.
rm(list = create_rf$names)
# Create a randomForest learner that optimizes over mtry
create_rf = create.Learner("SL.randomForest",
tune = list(mtry = round(c(1, sqrt(ncol(X)), ncol(X)))))
create_rf
sl = SuperLearner(Y = Y, X = X, SL.library = create_rf$names, family = binomial())
sl
# Clean up global environment.
rm(list = create_rf$names)
# Optimize elastic net over alpha, with a custom environment and detailed names.
learners = new.env()
create_enet = create.Learner("SL.glmnet", env = learners, detailed_names = T,
tune = list(alpha = seq(0, 1, length.out=5)))
create_enet
# List the environment to review what functions were created.
ls(learners)
# We can simply list the environment to specify the library.
sl = SuperLearner(Y = Y, X = X, SL.library = ls(learners), family = binomial(), env = learners)
sl
## End(Not run)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.