Function MOPT, ceff1, ceff2, and Deff return objects of class OPT. The plot-methods plot the verification plot of the multiple-objective optimal design (from function MOPT), the D-optimal design (from function Deff), the c-optimal design for estimating the ED50 (from function ceff1), and the c-optimal design for estimating the MED (from function ceff2).
signature(x = "OPT")