How to use fmincon function arguments object in app designer?

Dear all,

This is my first posting in this community. So, hello community.

While there are many Q&As that helped me out in the past, I am now struggling to implement an object as function arguments for fmincon in the app designer (also first time I am using it).

The object function is declared public:

    methods (Access = public)
  function sumsquares = wlcobj(app,PLo,lobs,Fobs)
      kbT = 4.1; % Room temperature 23.8°C
      lcalc=force2wlc7(app,Fobs,PLo(1),kbT,PLo(2));
      sumsquares=sum((lobs-lcalc).^2);
   end

When I call it for the function input arguments:

   x=fmincon('wlcobj',xo,[],[],[],[],xlb,xub,[],[],Extension,Force);

I get the error 'Undefined function 'wlcobj''.

I can certainly undertands that somewhat, since in the app designer one adds the 'app' information.

But I did not find any infor about how to do that.

Trying:

 x=fmincon(app, @wlcobj,xo,[],[],[],[],xlb,xub,[],[],Extension,Force);

leads to the error ' Error using fmincon (line 225). FMINCON requires the following inputs to be of data type double: 'X0'.'.

So, that seems also to be the wrong syntax. In normal Matlab, it works... but in app designer not.

Anyone that could give me a tip how I can reference correxctly to the 'wlcobj' object for the function input arguments?

Thank you in advance!

Cheers,

Richard

Answer 1

[Matt J]

It's not clear from your post where the objective function is defined and where (in what workspace) you are invoking fmincon. When you say "wlcobj" is a public method, I will assume you mean it is a method of your app class. Also, it is not clear from your code which variables are the unknowns and which are fixed parameters. If I assume that PLo is your unknown vector, then your invocation of fmincon should look like,

   x=fmincon(@(x)app.wlcobj(x, Extension, Force),xo,[],[],[],[],xlb,xub);

Note, however, that lsqcurvefit or lsqnonlin would be more apt for your problem, since they are specially designed for nonlinear least squares optimization problems.

See also,

https://www.mathworks.com/help/optim/ug/passing-extra-parameters.html

[Matt J]

Richard Janissen replied:

Hi Matt,

Thank you for your prompt reply.

You made me think about something that I should look closer at.

I'l come back to you.

Cheers,

Richard

[mojtaba rayati]

Hi Matt,

I have the same question and your answer helped me.

Thanks alot

[Matt J]

@mojtaba rayati I'm happy it helped, but please Accept-click the answer to indicate so.