How can i convert my user class object into a mex file?

I have read https://www.mathworks.com/help/matlab/matlab_external/mex-functions-for-class-methods-1.html that I can convert functions into mex file and call these functions in the object's methods.

But ones I try to convert the functions using the coder app, I receive the following error: Entry point cannot be inside a class folder.

What I am doing wrong?

My function, defined in the method class is a sort of:

function out = step(Obj)
modulated_sym = zeros(1,Obj.FEC*Obj.signal_config.n_sym);
for nn = 1:Obj.FEC
    %%%%%%%%%%%%%%%%%%%%%%%%%%%% Turbo Encoder %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    [coded_bits_to_punc] = step(Obj.signal_config.hTEnc,Obj.tx_bits((length(Obj.tx_bits)/Obj.FEC)*(nn-1)+1:nn*(length(Obj.tx_bits)/Obj.FEC)).');
    coded_bits_to_punc = coded_bits_to_punc(1:end-16);
    coded_bits_to_punc = [coded_bits_to_punc(1:3:end-2); coded_bits_to_punc(2:3:end-1); coded_bits_to_punc(3:3:end)];
    Obj.len_to_punc = length(coded_bits_to_punc);
    coded_bits = coded_bits_to_punc(Obj.signal_config.punc_pattern);
    .....
end

Is the " Obj." that is not working for the coder?

Answer 1

[Walter Roberson]

You cannot use MATLAB Coder to convert a class method into a mex file. You can only convert functions outside of classes.

This implies that the function to convert could only use the public interfaces to the object properties to get data or change the object.

[Daniele Nanni]

Thank you for you answer!

I understand. I have the problem that, in my project, I have to use different objects. And the speed of the entire program is very slow. I thought that converting some of the methods in mex file could be a good compromise.

Do you know any technique that is possible to apply to speed up the execution of the program?

Thanks a lot!

[Walter Roberson]

struct() are faster than objects. Carefully arranged numeric arrays are faster than struct() .

If you use a class folder, then the class folder can contain mex files. However, you cannot selectively convert class methods written in m-code into mex; furthermore, the mex API makes objects pretty much opaque, if I recall correctly.