Matlab doesn't give the same result if all functions put in one file

Hi all

I have one main file that runs a function (F1) that this F1 calls a second function F2 inside it. I need to put all of these functions into one single file to use them in one app.

but when I tried to run this single app, I see, that despite giving no error, just the solution is different that does not lead to the same result. true that I need to make some variables global that I have actually done.

I even copied the non working series of functions from the app back into an mfile code and there !! PAM !!! it works !! It seems that using global variables, the values are not passed correctly somehow but I don't know how ! and why

the function F1, calls the F2 in a loop and in each loop it should pass a value like :
for i=1:rows
    [result] = functionF2(l1,u1 , time(i,:))
end

Since the code is huge, I CAN'T share it here. BUT I wanted to know if there is any way to know the reason this kind of malfunctioning happens. the code runs smoothly when I have multiple files, but I can't find where the code works different, specially in second function F2 when I put all of them together. Any hints without seeing the code ?

[matquest]

Do you have unit tests for this? That should help you identify what/where the issue is. You can also enable a breakpoint at the top of your main function and use the "step"/"step in" features to see where the code goes during execution. Check the values going into and out of each function call. Do the same thing for the code that is in multiple files and you should be able to see where they differ.

[farzad]

shall you please explain the first method ? what is unit test ?

I don't understand : the break points could not be usefull in app designer right ? my problem is in the app designer.

but if I run the separate files, there is no problem that I could track ! it runs smoothly

[Geoff Hayes]

farzad - have you tried to not use global variables and instead pass in the variables to whatever function needs them?

[Mohammad Sami]

I think that you would not need to combine your functions into one file, to use with appdesigner.

Your functions can exist outside of the app, as long as they are in the working directory, your app can access them.

[Stephen23]

"It seems that using global variables..." is the problem.

You are discovering exactly why experienced programmers do NOT use global variables: because they make code unpredictable and difficult to debug. Solution: pass your data properly using (best practice) input/output arguments or nested funtions:

https://www.mathworks.com/help/matlab/matlab_prog/share-data-between-workspaces.html

Do NOT use global variables or magical assignin, evalin, etc.

[farzad]

thank you very much, any reason why it work in MATLAB base but not in app designer ?

also, If I nest the function F2, I will need o call it from F1 in a loop, I am not sure it will be feasible then

[farzad]

I have the urgency to put them into one single app cause then I need to compile them. If I leave the multiple files then it will not get compiled into one exe and m files will remain outside of the exe file which is not what I want.

I still don't know how to debug it inside app designer, cause the code is huge and if I want to pass all the variables into base it will not be easy.

[Stephen23]

"I have the urgency to put them into one single app cause then I need to compile them."

Then you will need to rewrite your code using reliable ways of passing data.

"if I want to pass all the variables into base it will not be easy"

Don't do that!

Process the data within the App/GUI function workspaces.

Making data magically jump between a GUI and the base workspace is one way that beginners force themselves into writing complex, buggy, inefficient GUIs, by relying on evil anti-pattern global variables, evalin, assignin etc.

[farzad]

dear Stephen, what do you mean by Process the data within the App/GUI function workspaces ?

I could send you part of my code , but not in the post. is the messages activated on your profile ?

[Stephen23]

"what do you mean by Process the data within the App/GUI function workspaces ?"

Call the GUI (with input arguments if required).

Process everything inside the GUI callback functions (this can include loading file data, calling other functions, etc.)

Return/save the data when the GUI is closed.

TIP: if there are many input arguments (e.g. parameter values) put them into a structure and pass that.

[Walter Roberson]

If I leave the multiple files then it will not get compiled into one exe and m files will remain outside of the exe file which is not what I want.

The application compiler for App Designer will usually find all dependencies and will automatically compile them in.

The situations that it might not notice include:

• if you pass the name of function instead of a handle to a function, such as ode45('MyFunction', ...)
• if you specify a callback as a character vector instead of as a function handle. This is more of a concern for old GUIDE programs than for App Designer
• hardware support packages that do not use functions of their own. For example, hardware support for image acquisition toolbox might not realize which hardware was needed

In such cases, you can add the .m file as "additional resources" or similar at the time you compile.

[farzad]

Thank you so much Stephen and Walter ! I solved it ! It was a for loop counter with a common name with another counter inside the second function being called inside the First function loop.

therefore the counter color in app had become blue and was warning me that this counter is changing its value.

strange that this same code did not experience any error and gave the right result in matlab base

[Walter Roberson]

If it became blue then you probably accidentally ended up with nested functions.