MATLAB: FMINCON – Failure in initial objective function evaluation. FMINCON cannot continue

Question

I am trying to solve a bar optimization problem, passing the initial conditions (the area of each bar) and all variables as a struct but I am facing the following problem:

 "Failure in initial objective function evaluation. FMINCON cannot continue."
fem = struct(...
    'x',x0,...                   % Initial set of points
    'NODE',NODE,...              % [NNode x 2] array of nodes
    'ELEM',ELEM,...              % [NElem x 2] array of elements
    'v',{v},...                  % Cell defining the variables
    'NNode',size(NODE,1),...     % Number of nodes
    'NElem',size(ELEM,1),...     % Number of elements
    'NVar',size(v,1)...          % Number of variables
     );
    Plot10bar(fem);
    mass = GetMass10bar(fem);
    fprintf('Initial Mass = %f\n',mass);
    [x,fval,exitflag,output,lambda,grad,hessian] = ...
        fmincon(@GetMass10bar,x0,[],[],[],[],lb,ub,@GetConstraints10bar,options);   
    mass = GetMass10bar(fem);
    fprintf('Final Mass = %f\n',mass);
    Plot10bar(fem);

Thank you,

André Leitão

Answer 1

I solved it using this:

    [x,fval,exitflag,output,lambda,grad,hessian] = ...
    fmincon(@GetMass18bar,x0,[],[],[],[],lb,ub,...
    @GetConstraints18bar,options,fem);