Using the Optimization Module for geometry examination

Geometry optiization 4.3a
Simple 1D sold state battery problem (in COMSOL)

Done with assistance from COMSOL
M = length of anode 320 nm
L = length of solid electrolyte 1500 nm

objective function = external voltage
time to 2000 sec (time dependent)

If L & M are listed with the mins and the max, no problem.

However if they are coupled - L+M= 1820 nm there seems to be no way to include this in the optimization module.

Does anyone any any ideas?

Thanks

--
Arthur Rupel