Workflows encompasses the three main stages of the modeling process: pre-processing of data, model fitting, and post-processing of results. This page enumerates the possible operations for each stage that have been implemented to date.
The two elements allowed for pre-processing are:
A standard model
formula via add_formula().
A recipe object via add_recipe().
You can use one or the other but not both.
parsnip model specifications are the only option here,
specified via add_model().
When using a preprocessor, you may need an additional formula for
special model terms (e.g. for mixed models or generalized linear
models). In these cases, specify that formula using
add_model()’s formula argument, which will be
passed to the underlying model when fit() is called.
Some examples of post-processing the model predictions would be: adding a probability threshold for two-class problems, calibration of probability estimates, truncating the possible range of predictions, and so on.
None of these are currently implemented but will be in coming versions.