The "run" command does not work in GARDER.

A script using Multi Start to search for a global minimum works in MATLAB, but an error appears in GARDER:

Error: You may not use the command(s) run in your code

Why does this happen, and how can you prevent it?

kol101=@(x)x.^2+2*sin(x.^2)+exp(-x);
opts = optimoptions(@fmincon,'Algorithm','sqp');
problem = createOptimProblem('fmincon','objective',...
    kol101,'x0',3,'lb',1.2,'ub',4.8,'options',opts);
ms = MultiStart;
[xmin,fmin,flaga] = run(ms,problem,20)
fplot(kol101,[1.2,4.8])
hold on
plot(xmin,fmin,'rp')

Answer 1

[Cris LaPierre]

I assume you are refering to MATLAB Grader. Certain commands and functions are not allowed when running code in MATLAB Grader, including run. However, the aim was likley to prevent use of the run function, which would allow users to circumvent restrictions an instructor places on solving a problem.

Ok, that's the why. In your case, you are not using the (very overlaoded) run function. Instead, you are calling an object function of MultiStart. That provides the workaround you need to use MultiStart in Grader. There are two ways to invoke a method (a.k.a. object function), which you can read about here.

• obj.methodName(arg)
• methodName(obj,arg)

Use the first syntax with dot notation, and the code will run in Grader

kol101=@(x)x.^2+2*sin(x.^2)+exp(-x);
opts = optimoptions(@fmincon,'Algorithm','sqp');
problem = createOptimProblem('fmincon','objective',...
    kol101,'x0',3,'lb',1.2,'ub',4.8,'options',opts);
ms = MultiStart;
[xmin,fmin,flaga] = ms.run(problem,20)

MultiStart completed the runs from all start points. 

All 20 local solver runs converged with a positive local solver exitflag.

xmin = 2.0510

fmin = 2.5856

flaga = 1

fplot(kol101,[1.2,4.8])
hold on
plot(xmin,fmin,'rp')

[Zbigniew Garncarek]

Thank you very much for the explanation.