Starting with version 1.40 GenetiCode can optimize master parameters of the underlying CODE configuration. Similar to the handling of thickness values, you have to specify a range of possible values [minimum … maximum] for each selected master parameter. During the evolution GenetiCode will then try to find the best solution.
Master parameters can be used to compute model parameters by the evaluation of user-defined expressions. You can use this mechanism to express restrictions of the design like one layer must have twice the thickness of another layer, or you can introduce temperature as a master parameter that governs optical constants and thickness values of a multilayer coating.
GenetiCode package 1.40 comes with an updated PDF that explains how the optimization of master parameters has to be defined.