Calling a Function in Matlab function block in Simulink.

Hello,

I want to call a function from a defined directory inside a matlab function block. I know that it can be done using 'coder.extrinsic () '. However I still get error as below

Expected either a logical, char, int, fi, single, or double. Found an mxArray. 
MxArrays are returned from calls to the MATLAB interpreter and are not supported inside expressions. 
They may only be used on the right-hand side of assignments and as arg

I know this can be solved by intitializing the variables, however in my case finding a required size is difficult and I do not know how else can I solve this, Is there anyway to intialize without defining a specific dimension of the variable?. I have also attached a picture of my function, please find below.

[VIGNESH BALAJI]

Did you face any problems while calling user defined functions inside matlab function block ? I faced this issue. If you have figured out a way, let me know

Answer 1

[Vidhathri LNU]

You can declare those variables as variable sized with an upper bound on the size. That should solve the issue

   function y = myfun(x)
   coder.varsize('y', [1024 2]); %x must never exceed 1024
   coder.extrinsic('fun');
   y = zeros(x, 2); %pre-declare the type and size of y
   y = fun(x);
   

Refer to the documentation here for more details on using coder.varsize.

https://www.mathworks.com/help/fixedpoint/ref/coder.varsize.html

[Prateek Tiwari]

Thank you for your response.

I already tries using coder.varsize(). In simulink it says this call back is not supoorted (MATLAB 2019B).