How to kill an execution in app designer ?

Hi All

How can I put a push button that has the same function of Ctrl+C in MATLAB workspace ? that can kill an execution immediately ?

Answer 1

[Ameer Hamza]

Use this undocumented MATLAB command to send a Ctrl+C to the MATLAB command window

com.mathworks.mde.cmdwin.CmdWinMLIF.getInstance().processKeyFromC(2,67,'C')

[farzad]

I tried it, nothing happens

[Ameer Hamza]

How did you tried it?

[farzad]

Didn't compile the application. Just created a new push button and copied this line under the button and opened the interface in app designer and tried it when I put it on a run

[farzad]

but there is one point, when I press the kill button once, and then go to Matlab and press the Ctrl+C, I get that Error message that claims the interruption appears twice. means that the kill button was somehow sent but did not get operative : because : the execution I have in my code is fsolve

[Ameer Hamza]

As you can see that even pressing Ctrl+C have no effect on fsolve. I am not sure there is any otherway to terminate it.

[farzad]

No you got me wrong, if I press the keys actually, but it doesn't, if I use the code.

Only that if I use the code, and then the keyboard, I can see from the errors, that the message from the code was sent but didn't take action

[Ameer Hamza]

If you let the fsolve() run for some time then even Ctrl + C have no effect. Atleast, on R2020a, I tried to terminate fsolve and it only terminated if I press it just after the start. If it do it after few seconds, then fsolve is not terminated.

[farzad]

no for me works at anytime. unless it is a memory isuue or overloading

[Ameer Hamza]

I am not sure about the issue. The Ctrl + C seem to be sent to MATLAB. It is strange that MATLAB does not respond.

[Yair Altman]

Just FYI, .getInstance() is not necessary since all CmdWinMLIF methods are static.

[Ameer Hamza]

Thanks, Yair, for your comments. Your website is truly a blessing for people like me who have no background in Java programming.

[farzad]

will the problem resolve with that ?

[Ameer Hamza]

No, it just equivalent to the code in my answer.

The only option which I can think of which might work in this case is to use the OutputFcn property of fsolve(). That outputFcn gives the option to terminate the fsolve() based on a condition. You just need to figure out a way to communicate button press to the outputFcn. For example, using a global variable (a simple approach but can cause issues in the long term) or pass a handle class to OutputFcn and change one of its properties based on the button press event. This is a general outline of the method. You can try it to see if it works.

Answer 2

[Image Analyst]

That's not a good idea. It would be better to abort your code gracefully. Like have a check box on your GUI that says "Finish Now" and if the user checks it, it gets out of your function gracefully and leaves your program running. Like if you're in a loop

for k = 1 : 1000000
    % Some intensive code.....
    % Now see if user wants to bail out:
    if app.chkFinishNow.Value
        return; % or break. to get out of the function (if return is used), or the for loop (if break is used).
    end
end

Doing it like you asked is very bad programming practice in my opinion, and probably most everyone else's also.

[farzad]

Thank you very much, should this box checked before hitting the start analysis or it can be also clicked during the analysis ?

I got an error :

Error: Reference to non-existent field 'KillAnalysisCheckBox'.

should I do :

if app.chkFinishNow.Value=true
    return; % or break. to get out of the function (if return is used), or the for loop (if break is used).
end

[Image Analyst]

No. If it were checked, it would abort immediately. What you'd do is this:

% Make visible to user and make sure it's unchecked.
app.chkFinishNow.Value = false;
app.chkFinishNow.Visible = 'on';
for k = 1 : 1000000
    % Some intensive code.....
    % Now see if user wants to bail out:
    if app.chkFinishNow.Value
        break; % Get out of the function (if return is used), or the for loop (if break is used).
    end
end
% At the end of the loop, make the Finish Now checkbox unchecked and invisible.
app.chkFinishNow.Value = false;
app.chkFinishNow.Visible = 'off';

[Matlab_Beginner]

Hey, i have a quick question, i'm new to matlab, and i want to do almost the same as the OP.

i got an infinite while loop in my script and i want to get out of it using matlab app.designer, therefore i created a start button to run my script, and a stop button to stop it.

I couldnt figure how to programme it,although u'v posted the code. How can i change the value of the while loop in my script (from true to false to stop excuting), if that's even possible.

i appreciate every help and thanks in advance!

[Image Analyst]

@Matlab_Beginner Please start your own, new question.

For any while loop you must have a failsafe that kicks you out once the loop counter reaches some unreasonably high number, like a million or something

loopCounter = 0;
maxIterations = 1e6;
while loopCounter < maxIterations || someOtherCondition
    someOtherCondition = whatever;
    loopCounter = loopCounter + 1;
end

[Matlab_Beginner]

Hey, thanks for ur quick answer. that s not exactly what im looking for. i want the user to stop the run whenever he want to via the stop button.

i made my own question: How to stop an infinite loop in my Matlab code via app designer? - MATLAB Answers - MATLAB Central (mathworks.com)