fmincon with external function as constraint

I use the fmincon to optimize the size of electrical motor. I also use the OctaveFemm toolbox to connect the Matlab with FEMM 4.2 solver. I have the function geometry.m which I use to load my model to FEMM (the inputs are dimensions of the machine). Next I use mi_analyse command to start FEMM calculations and after this I have the function torque_read which provides me the torque from obtained FEMM results as a value in Matlab.

I would like to add the optimisation constraint for torque range. Is it possible to implement my FEMM calculation procedure somewhere in fmincon function?

Answer 1

[Walter Roberson]

The nonlcon parameter expects a function handle. The function can call upon whatever other functions it wants. The requirements are:

• the nonlcon function must return two outputs (not a vector of length two), the first of which is the nonlinear inequality constraints, and the second of which is the nonlinear equality constraints. Return [] in the appropriate position if a constraint does not apply
• the inequality constraint is a vector or matrix output. Each entry must be negative or 0 to indicate that the constraint is not violated, with positive indicating a constraint violation
• the nonlinear equality constraint should be 0 when the constraint is not violated.