FLXPconstant specifies constant priors
and FLXPmultinom multinomial logit models for the priors.FLXPconstant()
FLXPmultinom(formula=~1)FLXP. FLXPmultinom returns an
object of class FLXPmultinom which extends class
FLXP directly and is used for method dispatching.FLXPmultinom uses nnet.default from