MATLAB command line output not following

Question

There is something very simple that can be very upsetting occasionally.

I sometimes want to keep track of the outputs of an algorithm at each iteration, so within a for loop, I use disp command of MATLAB to output some information. However, although there is quite a bit of time between the calling of dispcommands, the MATLAB command window falls behind and I need to use the mouse to keep up with it manually. Do you know if there is any way to have it not fall behind?

Thanks,

Out of curiosity, did you find a solution, like the short pause I suggested? — chappjc
– chappjc, Commented Dec 9, 2013 at 19:29
Yes! The short pause before dispcommand solved the issue. Thanks a lot. — dagcilibili
– dagcilibili, Commented Dec 10, 2013 at 12:54

chappjc · Accepted Answer · 2013-12-06 22:35:09Z

3

It really shouldn't fall behind, but I could see this happening if the computations are intensive and the MATLAB JVM, which drives the GUI, does get the resources to update the command window.

The following command may be of help:

drawnow update % or just drawnow

According to the documenatation page, this "causes only user-interface objects to refresh, if needed". If that fails, try just drawnow with no arguments to see if it helps to flush the entire system event queue, including graphics updates.

If that doesn't work you could insert a pause(0.01) or something similar as a last resort.

edited Dec 6, 2013 at 22:35

answered Dec 6, 2013 at 19:13

chappjc

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3 Comments

horchler Over a year ago

Not that there's really a difference, but I prefer to use the function form in code: drawnow('update');.

dagcilibili Over a year ago

Unfortunately it does not flush the command prompt. However this is a very useful command.

chappjc Over a year ago

Oh well. But I'd be willing to bet a pause(0.01) or similar would do the trick.

Jacob · Accepted Answer · 2013-12-06 18:27:02Z

1

It shouldn't fall behind if you don't use the mouse at all. However, I often use the waitbar for this purpose.

FEX also has several text & GUI progress bars.

answered Dec 6, 2013 at 18:27

Jacob

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1 Comment

horchler Over a year ago

I'd guess that waitbar has an implicit call to drawnow within it that would flush command window content.

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