Increasing Java Heap Memory of target machine so that EXE runs on target machine with MCR

This helps with increasing Java Heap Memory on the developer machine

https://in.mathworks.com/help/matlab/matlab_external/java-heap-memory-preferences.html

If I have a target machine that has only the MCR intalled... which hangs because of "" how do I increase the Java Heap Memory relevant for Matlab EXE on that machine? What should I tell the user on Windows 10 to do? Will increasing it using the "Control Panel - Programs - Java" be good enough? (i.e. http://www.messiahpsychoanalyst.org/wikihow/index.php/How_to_Increase_Java_Memory_in_Windows)

Or is there some way to specifically increase it for Matlab based EXE that run on the MCR?

[Guillaume]

Why do you want to increase the Java Heap Memory (which would decrease the memory available to matlab to store non-java stuff such as matrices)?

[Purnendu Nath]

Because when my (appdesigner) app crashes after doing (say 1010) simulations for no apparent reason (e.g. if I restart it at 1009 it continues again) the red error message in the command window includes the following:

java.lang.OutOfMemoryError: Java heap space

[Guillaume]

In tha case, then indeed incresing the java heap may help. However, it would be interesting to find what is exhausting the java memory. appdesigner apps don't rely on java as far as I know.

If you can attach your app code, so we can look into it. Or raise a bug with Mathworks if your license allows it.

Answer 1

[Bruno Luong]

According to my test, the stand alone app uses the sames amount of java heap memory than your MATLAB preferences.

To set the amount of Java heap memory you can either uses the menu in the toolstrip

Menu Preferences -> General - Java Heap Memory

or edit the file prefernce file

>> edit(fullfile(prefdir,'matlab.prf'));

the put desired amount of the memory in Mb in the line (here 1Gb)

JavaMemHeapMax=I1024

Then compile your app

On Windows platform if you want to change the Heap after compilation. Run the app once then close it. then goes the folder

C:\Users\XXX\AppData\Local\Temp\XXX\mcrCacheM.N\APPNAME_YYY\.matlab

where XXX is the user name, M.N, APPNAME depends on your MCR version and application name, edit the line

JavaMemHeapMax=I1024

then relauch your app.

[Purnendu Nath]

Having set it, is there a command line (or shell command) that I can use to inspect what value it has been set at without opening the .prf file? I would like to be able to click a button on my stand alone app and get a message that tells me what the JavaMemHeapMax setting is on machine running the stand alone app.

[Bruno Luong]

Use this (at the start of your application)

fprintf('Java memory = %d Mb\n', round(java.lang.Runtime.getRuntime.maxMemory/1e6));

[Aubai]

Hallo Bruno,

This is exactly what i am looking at but the problem is that i can not find JavaMemHeapMax variable in my matlab.prf file on the computer runing the MCR. (I found the file but did not find the JavaMemHeapMax inside it) Can you help me with that??

Best Regards

[Bruno Luong]

What Matlab/MCR version are you using?

If you can't find it, just add the line (in my setup it's the line #7 in the file matlab.prf)

JavaMemHeapMax=I768

and see if has any effect.

[Aubai]

Hallo Bruno,

Thanks alot it did work by adding it. but what i am not understanding is that the app is now limiting itself to a very low value which is less than what i have given in the JavaMemHeapMax=I7000

is there other limitation that is directly affected by this?

is there anyother memory values that i can menipulate?

Best Regards

[Bruno Luong]

Please open new thread describe in detail your app does and error message you get.

[Aubai]

Hallo Bruno,

Thanks very much for the support and i already did here but with the old (first) question i had at the start.

this is the idea the app is not giving me any errors (Windows is doing so so when i am using the App with JavaMemHeapMax =I0 windows is losing it and telling me that i need to close my App as it is using alot of memory).

after playing with the JavaMemHeapMax then the memory at some time is limiting itself to a very low value lower that the set value in JavaMemHeapMax which i can not understand or explain.

I even asked a question about memory limitation of Matlab EXE Apps here also

Best Regards

Answer 2

[Purnendu Nath]

Bruno, all of the above has worked perfectly...

Thanks a lot!