Updates the utility function to consider dummy coded attributes. It will expand the dummy-coding to K-1 dropping the lowest level. This is consistent with standard practice.
An object of class utility
An updated cleaned utility expression
The function is called prior to evaluating designs if dummy-coded attributes are present in the utility function. This is because the utility function is evaluated in the context of the design environment and must be added there
Important to note about the naming of the expanded priors and attributes: The names for the attributes will be attached with the level of the factor, whereas the prior will be named corresponding to the level, e.g., 2, 3, 4. This is simply the result of the difference between how it's extracted from the utility functions and how model.matrix creates names.