fitting function as a sum of different contributions

Hello, I'm fitting my experimental data with a function that can include several terms, each dependant on several parameters, lets say F([a1,a2,...,an],x)= F1([a1,a2,a3],x) + F2([a4,a5],x) + ... Fi([an-1,an],x) Sometimes I can neglect one of the terms, sometimes I can neglect another one, sometimes several of them. I'm making a gui to make the fitting procedure as convenient as possible and I'd like to have e.g. tick boxes referring to each of the terms that can be checked or unchecked, depending on what one wants to be included in F. Of course, I can manually write many combinations of fitting functions and corresponding inputs and outputs, but I'm sure there is an easier way to make an instruction "if tick 1 is checked include term1 in F" I'd appreciate any suggestions

[Joshua]

The answer on this thread should help: https://www.mathworks.com/matlabcentral/answers/13351-dialog-with-checkboxes-in-gui