The function validates the user supplied list of model options and sets defaults for missing options. All checks are intentionally aggressive and will throw an error rather than make assumptions about what the user intended to do.
A user supplied list of model options
A character string of variable names in the data
A list of model options with missing input values replaced by default values
The function is run once inside of
prepare to correctly set up
the estimation environment. It is meant for internal use only and is not