How to run and analyze a big Matlab class code line by line.

I am new to Matlab classes and I am working on a big Matlab class (600+ lines in total) where I need to check outcome from each executable line in terms of variables being used and returned and their size, type etc. so that I can remove unnecessary variables and preallocate all necessary variables. I tried putting break points but it seems that Matlab goes upto end of methods and not beyond that where actual work starts. I am aware of mlint, tic-toc and profiler for optimizing Matlab codes but for that I need to run the whole thing first. Can anyone please let me know if it is posssible at all to run a Matlab class with breakpoints?

[Geoff Hayes]

Yes, it is possible to put breakpoints in a class definition and have the code break in the appropriate place. I often do this.

Note that if you ever change the code, then you must run clear all to refresh the class definition. Maybe that is why you are having problems - changes are being made to the class definition, a new instance of that class is created using the old definition and stepping through the code is confusing.

[Cedric]

Note that e.g.

 clear all

clears all break points. Therefore, if you have a script in which you create an object based on a classdef which contains break points, if the script starts will clear all, your break points are gone. So keep in mind that you may have to comment out a few calls to clear before you run the script.

Answer 1

[James Kristoff]

You can place a breakpoint at any point that you would like to ensure you stop at. I am not sure what you mean about work starting after the end of the function. In a MATLAB class, all 'work' happens inside of the class's methods. If, for example you have the following class:

classdef foo < handle
    properties
        bar
    end
    methods
        % class constructor
        function obj = foo(obj)
            obj.bar = 'hello';
            % do some work
            obj.doWork();
        end
        function doWork(obj)
            disp(obj.bar);
        end
    end
end

and you then want to see how this class works you can put a breakpoint on the line:

obj.bar = 'hello';

and the execute the command:

aFooObject = foo;

in MATLAB®. This should stop at the breakpoint, and then you can step through the code using the F10 key (in Windows). When you get to the line:

obj.doWork();

you can step into this function using the F11 key (in Windows), which will allow you to debug the doWork() function as well.