error in ga optimization code

Here is the code I'm trying to run for optimization

function finalResult = OptimizeScript()
% Decision variables are the
%   Servers Capacity
%   Process Time

% These are set by the genetic algorithm as it runs multiple
% simulations of the OptimizandMask model via the variable
% ResourceCapacity.

% Open a parallel pool
%pool = parpool;

% Setting plot and parallelization options
opts = gaoptimset(...
    'PlotFcns', @gaplotbestf, ...
    'Generations', 25, ...
    'StallGenLimit', 10, ...
    'UseParallel', 'always');

% Loading the model to run on all parallel workers
%pctRunOnAll('load_system(''OptimizeandMask'')');
load_system('OptimizeandMask');

% Lower bound of decision variables
lb = [1 5];

% Upper bound of decision variables
ub = [10 15];

% Integer constraints: If the third was not an integer, it would be [1, 2,
% 4]
IntCon = [1 2];

% Track time spent for optimization
tic;

% Execute genetic algorithm solver
[finalResult, ~, ~] = ga(@productionCost, 2, [], [], ...
    lb, ub, [], IntCon, opts);
toc;

% Shut down the parallel pool
%delete(pool);

end

% Cost function that assign different values to the decision variables in
% the model
function obj = productionCost(ResourceCapacity)
% Assigns costs to the values of ResourceCapacity, which correspond
% to [batch reactors, water tanks, heaters, drains]
cost = [1000 -200] * ResourceCapacity';

% Assigns variables to the base workspace for simulation
assignin('base', 'ResourceCapacity', ResourceCapacity);

% Simulation of the model and assigns output to the variable z
if isempty(find_system('type', 'block_diagram', ...
        'Name', 'OptimizeandMask'))
    load_system('OptimizeandMask');
end
set_param('OptimizeandMask/ConfigResource','ServerCapacity', ...
    num2str(ResourceCapacity(1)), 'ProcessTime',...
    num2str(ResourceCapacity(2)));

[~, ~, z] = sim('OptimizeandMask');

% Takes the last value of the logged data as the final backlog
% value
backlog = z(end);

% Calculates the objective function, based on the backlog and costs
obj = backlog*10000 + cost;

end

but Matlab is giving error

Error using functionHandleOrCell (line 12)
The constraint function must be a function handle.
Error in validate (line 228)
    [nonlcon,NonconFcnArgs] = functionHandleOrCell('NonconFcn',nonlcon);
Error in gacommon (line 65)
[options,nvars,FitnessFcn,NonconFcn] =
validate(options,type,nvars,fun,nonlcon,user_options);
Error in ga (line 363)
    NonconFcn,options,Iterate,type] = gacommon(nvars,fun,Aineq,bineq,Aeq,beq,lb,ub, ...
Error in OptimizeScript (line 38)
[finalResult, ~, ~] = ga(@productionCost, 2, [], [], ...

I am unable to understand the error and solution because the syntax seems correct to me. can anybody help me out?

Answer 1

[Walter Roberson]

You missed the Aeq and beq parameters.

[Alan Weiss]

In other words, this line of your code is incorrect:

[finalResult, ~, ~] = ga(@productionCost, 2, [], [], ...
  lb, ub, [], IntCon, opts);

Instead, it should be

finalResult = ga(@productionCost, 2, [], [], [],[], ...
  lb, ub, [], IntCon, opts);

Alan Weiss MATLAB mathematical toolbox documentation

[summyia qamar]

I understand now the error but can you please explain the difference in

[finalresult,~,~] and simple finalresult.?

[Walter Roberson]

In some cases, using trailing ~ like you show in [finalresult,~,~] can result in extra computation for no useful reason, but in most cases there is no effective difference. It is better not to add trailing ~ like that.