Problem when using max operation in objective function of fmincon optimization

Hi. I have a problem when I use max operation in objective function of fmincon optimization. My code of objective function:

function J = Minimized_Function(x)
A = sub_function_1 (x);
B = sub_function_2 (x);
C = sub_function_3 (x);
J = max(A,B,C)
where sub_function_1, sub_function_2, sub_function_3 are certain funtions.

Operation max(A,B,C) seems to make my objective function become discontinuous. As a consequence, I cant get the right result of optimization process despite that fact that the code works.

[Bruno Luong]

Operation max(A,B,C) seems to make my objective function become discontinuous

Nope it makes your objective function not differentiable, whereas FMICON requires the derivative exists and continuous.

[Nguyen Phuoc]

Thanks. Do you have any suggestions to deal with this?