MATLAB: Cannot load ‘ClassificationKNN’ in a compiled executable, issue with classdef

Question

I have a model that was trained using the fitcknn function.

I save it as a *.mat file, load it into my Matlab programs and it works fine.

I then compile the code, run it, and when it tries to load the aforementioned mat file, it gives me a warning saying

Warning: Variable 'b' originally saved as a ClassificationKNN cannot be instantiated as an object and will be read in as a uint32.

I've found this Matlab question with someone having the same problem http://au.mathworks.com/matlabcentral/newsreader/view_thread/261903

But they are using their own class, it was solved because his classdef wasn't on the path, so putting it there solved his problem.

So do I need to find the original Matlab classdef for ClassificationKNN and somehow make it accesabile to my executable file? If so how? Or am I way off?

Thanks for any help in advance!

Answer 1

When you LOAD an object from a MAT-file, MATLAB needs the class definition to tell it how to convert the raw data into an object. When you create a compiled application, MATLAB analyzes your code to determine what functions need to be part of that compiled application. I'm pretty sure that analysis doesn't "look into" MAT-files to determine what functions it may need when that MAT-file is loaded.

I think using the %#function pragma to include the object constructor (ClassificationKNN) or explicitly listing the class definition file as a required file using the Application Compiler app will resolve this issue for you.