Creates a deep copy of an 'xgb.Booster' object, such that the
C object pointer contained will be a different object, and hence functions
like xgb.attr() will not affect the object from which it was copied.
Value
A deep copy of model - it will be identical in every way, but C-level
functions called on that copy will not affect the model variable.
Examples
library(xgboost)
data(mtcars)
y <- mtcars$mpg
x <- mtcars[, -1]
dm <- xgb.DMatrix(x, label = y, nthread = 1)
model <- xgb.train(
data = dm,
params = xgb.params(nthread = 1),
nrounds = 3
)
# Set an arbitrary attribute kept at the C level
xgb.attr(model, "my_attr") <- 100
print(xgb.attr(model, "my_attr"))
# Just assigning to a new variable will not create
# a deep copy - C object pointer is shared, and in-place
# modifications will affect both objects
model_shallow_copy <- model
xgb.attr(model_shallow_copy, "my_attr") <- 333
# 'model' was also affected by this change:
print(xgb.attr(model, "my_attr"))
model_deep_copy <- xgb.copy.Booster(model)
xgb.attr(model_deep_copy, "my_attr") <- 444
# 'model' was NOT affected by this change
# (keeps previous value that was assigned before)
print(xgb.attr(model, "my_attr"))
# Verify that the new object was actually modified
print(xgb.attr(model_deep_copy, "my_attr"))