Leon - where have you defined your objective and constraint functions relative to the "main" code (i.e. that code where you create myHoltropObject, set up the optimization problem, etc.)? Are they in separate m-files? Is your main code a script?
The error message is suggesting that when the objective function is called (or even the constraint function since it calls the ojective function too), that the myHoltropObject.getR_T is unknown. If these two functions are defined in separate m-files, then they won't "know" about this object. If this is the case, then I recommend that you put your main code in a function and then nest the constraint and objective functions so that they have access to the variables defined in the parent/main function. Perhaps something like
function myMainFunction
myHoltropObject = Holtrop_R_T(12.86, 900);
x0 = [50 12 3.2 -4.5];
lb = [40 10 3 -5];
ub = [60 15 5 5];
gs = GlobalSearch;
options = optimoptions('fmincon','Algorithm', 'interior-point',...
'UseParallel',true, 'Display','off','MaxFunctionEvaluations',6000, 'TolCon', 1e-4, 'TolFun', 1e-4);
objectiveA = @(in) calcRT(in);
constraintA = @(in) RT_equal84(in, calcRT);
problem = createOptimProblem('fmincon', ...
'objective',objectiveA, ...
'x0',x0, ...
'lb',lb, ...
'ub',ub, ...
'nonlcon',constraintA, ...
'options',options)
% Run optim search
%[resultVector,~,exitFlag,~,~] = run(gs,problem); % this is for global optimization
[resultVector,~,exitFlag,~,~,~,~] = fmincon(problem) % this is for local search of optimum
% Objective function
function RT = calcRT(in)
Lwl = in(1);
B = in(2);
T = in(3);
lcb = in(4);
RT = myHoltropObject.getR_T([Lwl B T lcb]);
end
%Constraint function
function [c, ceq] = RT_equal84(in)
RT = calcRT(in);
ceq = RT-616;
c = [];
end
end
where the above code is saved to a file named myMainFunction.m. This may help. Please see nested functions for more information.
