How should I release memory while running an AppDesigner app without having to restart MATLAB?

Hello,

I built a software to read and communicate voltage data to LabJack. The software sends voltage to three pistons in order to apply a load scheme that follows a sine wave. It also reads voltage from load cells and reads the displacement of the pistons (all of this data is presented to the user on the GUI- see picture). The software is meant to run for at least 3 weeks to control a lab experiment. However, MATLAB seems to consume all of my lab computer memory on day 5 which is not ideal for the conditions of my experiment.

The app relies on three timers with period 200 ms (one timer for each chamber/piston) to communicate voltage values with LabJack and another set of three timers that update every second to present numerical values of load and displacement.

I have looked thoroughly for a solution and I cannot seem to find any piece of code or information on how to release the memory being used by MATLAB without having to restart MATLAB.

I also noticed that closing the Appdesigner software does not release any memory. Starting a new experiment on the software which involves clearing variables also does not release any memory. The only way to release memory is by restarting MATLAB, which is not ideal. So I wonder if there is a better way to solve this issue?

BTW the plot in the GUI only plots the last 30 seconds of data and it updates every 200 ms.

Thanks,

Ward

[Khaldoun Swid]

evalin('base','clear all' )

Answer 1

[Mario Malic]

Hi Ward,

Do you use persistent variables? See in task manager which process has high memory usage, MATLAB or MATLABWindow?

Here's a link of different clears that you could do, try clearing in this order and see at which one memory will be released.

clearvars
clear functions
clear classes 
clear all

[WSS]

Mario,

Thanks for your response. I tried the codes you provided but none worked. When I used "clear classes" MATLAB produced a warning that it could not clear the app classes or any of its superclasses.

Task Manager shows MATLAB to use a lot of memory please see attached screenshot.

[Bruno Luong]

I have observed memory leak in my GUI (no app designer) using opengl hardware. In my case I use opengl sofware and all memory leaks are gone.

[Mario Malic]

Just to try this option as well, since I forgot to mention it

clear

Do you use functions like evalin or assignin? When you get this warning about clearing classes, can you try Ctrl+C and see if you get any error or another warning? Probably, it's better to consult with customer support, this is quite a specific case.

[WSS]

Mario,

I tried using

clear

It does not do much. I also do not use any of the functions you mentioned.

CTRL+C will stop the timers and produce an error related to that event although it still does not clear memory.

I will contact customer support and see what they think.