If a multivariate response transformation was used in fitting the model,
its name is auto-detected, and in that case we need not specify fcn
as long as its inverse can be found in the namespace of the compositions
package. (That package need not be installed unless fcn
is a character
value.) For some such models, auto-detection process throws a
warning message, especially if cbind
is also present in the model
formula.
Currently, no bias-adjustment option is available.