MATLAB: Matlab doesn’t release memory when variables are cleared

memory problems.

I am working with very large data sets (~50 GB) in matlab R2015a. When I clear variables, matlab frequently does not release the memory. I have tried clear all, clear classes, clear java and running the java garbage collector. The only way I can get matlab to release the memory is close and restart matlab. Is there a better way?

Best Answer

It has more to do with Windows and how its memory-management routines work (or not) regarding what memory that is marked as unused by the application is actually physically released and when. Also, even though there may be sufficient total free memory, it is free contiguous memory that is limiting when creating arrays; if there isn't sufficient for the job, you're stuck.

There are guidelines to help and also some newer techniques more recently introduced you can try--

<efficient-use-of-memory>

<large-files-and-big-data>

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There are 2 mistakes in the above implementation:

Accessing a frame of frameBuffer as frameBuffer(i) instead of frameBuffer(:,:,:,i)
The function shiftBuffer changes the values of frameBuffer locally in the function and in the main code the frameBuffer isn't changed.

I suggest you to make the following changes.

Change the function shiftBuffer as follows:

function frameBuffer = shiftBuffer(frameBuffer,frame,framesInBuffer)
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and the following lines in your code

frame = readFrame(videoObject);    
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% We update the framesInBuffer counter

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