return: Should we just return a list with just the vector of assignment ("group") or a list with the vector of assignments and the vector of latent variables ("full")?
Returns
A list with some or all of the following elements.
x: The group assignment. 1L for one group and 0L for the other group.
w: The latent assignment vector (only returned if return = "full"). Negative corresponds to one group and positive corresponds to the other group.