Why does Matlab execute my code sometimes twice?

Sometimes when I press the run button in the Editor, the code is executed twice (or even more times). I can't exactly define when it happens, but it happened even to this very simple program code:

clear all
for z=1:5
   z
   pause(1)
end

Have you experienced similar problems? Any idea why it can happen?

[Jan]

Which OS and which Matlab version are you using?

[ES]

The file name is not 'z.m' hopefully. That is my suspicion.

[Andreas Goser]

How do you know whether the code runs twice?

[Bence]

I'm using 2010a at my workplace under Windows 7. The file name was not 'z.m' - it would have caused an infinite loop. In the simple case I shared Matlab wrote the numbers in the command window from one to five twice.

[Robert Laws]

I had not encountered this problem until recently (2021a) . It behaves exactly as if I have pressed the "run" button in the editor twice, but not every time - just once in a while.

It is, naturally, very annoying especially if the code takes a long time to run and begins with a 'close all'.

[Alvin Stroyny]

Same issue!

[Image Analyst]

@Alvin Stroyny, then same answer. Either you are calling it recursively or clicking the button twice. Maybe your keyboard is not being properly debounced - try a new one. Or try putting a breakpoint there.

[John D'Errico]

Since this happens after a mouse click, I might check to see if you have some issue with your mouse. For example, swap a different mouse in. Or, see if it also repeats when using the run command directly, since you can run a script from the command line.

Answer 1

[Image Analyst]

Most likely, you clicked on the green "Run" triangle twice, or you typed F5 twice. Either of those will cause it to run once, then immediately run again after it finished (I actually tried it).

[Bence]

Thanks for your answer. You are right that clicking the Run button twice makes the code run twice but since I recognised this problem I tried to click the Run button cautiously in order not to click it twice accidentally. And it doesn't explain why the same code once ran 7 times (not kidding).

[Image Analyst]

Step through it one line at a time and see where it goes after you reach the end of the code.