MATLAB: Function ‘fmincon’ not supported for code generation

fminconMATLABsimulink

Hello,
im currently trying to implement nonlinear MPC in MATLAB/Simulink using the MATLAB function block.
function u_mpc = MPC(x, u_mpc, u_0, A_ineq, b_ineq, Q_mpc, R_mpc)
costfunc = @(x,u) (x)'*Q_mpc*(x) + (u_mpc)'*R_mpc*(u_mpc);
 
u_mpc = fmincon(costfunc, u_0, A_ineq, b_ineq);
end
The state x is provided by a plant model, the costfunction is a simple quadratic cost with weight matrices, the matrices are taken from the workspace.
Running the Simulink model results in the error: Function 'fmincon' not supported for code generation.
I'm using the 2018b version normally, tried using 2021a but got the same error.
Is there a mistake in the code or is it simply not possible to use fmincon inside a MATLAB function block?
Thanks in advance for any help.

Best Answer

fmincon codegen support was added in R2019b. Also, optimOptions is the last argument for fmincon, you should pass other arguments as empty ([]) if you are not using them. For example,
function u_mpc = MPC(x, u_mpc, u_0, A_ineq, b_ineq, Q_mpc, R_mpc)
    costfunc = @(x,u) (x)'*Q_mpc*(x) + (u_mpc)'*R_mpc*(u_mpc);
    options = optimoptions('fmincon','Algorithm','sqp');
    Aeq = [];
    beq = [];
    lb = [];
    ub = [];
    nonlcon = [];
    u_mpc = fmincon(costfunc,u_0,A_ineq,b_ineq,Aeq,beq,lb,ub,nonlcon,options);
end
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