CODEWITHSUNDEEP
matlabmemory
Bhargav Achar
Bhargav Achar

Reputation: 21

How to clear virtual memory without closing matlab?

I am working on activity recognition but am getting an out of memory error after processing one video.

The maximum possible array turns from 444mb to 84mb, which means it can't process more than one video. Using clear all; and close all; we can just clear the matlab memory, but how do we clear the virtual memory (ram) space without closing matlab?

Any help would be much appreciated.

Upvotes: 2

Views: 9821

Answers (3)

aasharma90
aasharma90

Reputation: 41

If run-time is not an issue for you, you may try using matfile that will let you access/load/save your data on your hard drive rather than RAM, but as your would expect, the process might be slow.

Another option that I tried while working on my problem is to convert my data to single precision, this should reduce the memory consumption by half. For videos and images, I believe that most of the work is doable using single instead of double precision. Of course, if you could, then further using them in uint8 will reduce the consumption by 8.

Related to your original problem, I think there is actually no solution for that other than restarting matlab everytime.

Upvotes: 0

Dennis Jaheruddin
Dennis Jaheruddin

Reputation: 21563

If you have to do all of them simultaneously, there probably is not enough memory. However I assume you want to process them sequentially. As mentioned in this question, you may have to resort to closing matlab and restarting it.

This may sound awfull, but with a little work you can ease the pain.

Here are steps you can take:

  1. Make sure your progress is written on disk in a convenient way, for example a .mat file with the list of numbers that still need to be processed.
  2. Write a wrapper function. This function should just:
    • Open the list
    • Make sure the next item from the list gets processed
    • If there is something left in the list, open a new matlab session where this function is called, and closes the existing session

The last part may not be easy to find, but suppose the function you want to call is magic(5), then it would be something like this:

!matlab -r "magic(5)" &
exit

Upvotes: 1

Roberto
Roberto

Reputation: 287

Java Heap Cleaner seems to work fairly well. But if you try and call it after you get a "Java heap space" type of error, it may or may not help, I haven't quite figured out if there's a pattern.

Edit: Try also the

pack

command. That forces Matlab to run the garbage collector on its own memory, while the Java Heap Cleaner does the same thing but on the Java memory.

Edit 2: I found out that you don't need to download Java Heap Cleaner to run the JVM garbage collector. You can also go for:

java.lang.Runtime.getRuntime.gc;

That seems to work quite well for me.

Upvotes: 0

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