how to specify java heap size on cluster?

I am trying to run matlab on a cluster. I need to increase the java heap size in matlab, but since it's a cluster, I can't use the GUI method to do this. Is there a command line flag to specify the java heap size on start-up? Something like matlab -nosplash - Xmx.... Or, is there a start-up options file on the cluster that I can edit? I have read about editing the java.opts file or the startup.m file, but it seems like these would not be allowed on a cluster.

Answer 1

[Abel Szkalisity]

You may want to check out this post: https://se.mathworks.com/matlabcentral/answers/74296-change-java-heap-memory-settings-without-starting-matlab

But honeslty, to me none of the answers suggested there solved my problem (namely to increase the java-heap size on the cluster).

It turned out (at least the experience shows), that the environment variable _JAVA_OPTIONS is overriding the settings both in java.opts and in the matlab.prf file. On linux try sg like:

export _JAVA_OPTIONS=-Xmx2048m

in your command line before starting matlab to increase the heap space. This worked for me on R2019a in a linux cluster.

[Saadia Karim]

What about Windows 10 Matlab R2020a. I am facing jave heap memory issue.

[Walter Roberson]

@Saadia Karim is that a Windows 10 cluster? Or is that a Windows 10 desktop MATLAB use?

[Saadia Karim]

i found the solution for the Java Heap Memory by installing Java SE Runtime Environment Latest verison (java_8u291)and increase the parameter to 4Gb using -Xmx4096m in Runtime parameter tab. and this help in not only in Matlab R2020a but also in other application too.

[Martin Lechner]

This solution works perfectly for my standalone Matlab applications on Linux calculation clusters.