Rose mpi launch

[steoxley]

@matthewrmshin I have tested this in my own space and with:

rose test-battery t/rose-mpi-launch

and also demonstrated that without the fix the modified test fails. I decided to use file size (ulimit -f) rather than stack size as that is the default value that -H or -S reports. In practice -a is the option we would normally use, but that produces many lines of output and would have been harder to create a control.

[scwhitehouse]

I'm unsure what the motivation for this change is, can someone explain why the change is necessary?

[steoxley]

Apologies, most of the initial work and reasoning was communicated by email. The particular use case for this option, as described in the header of the script, is:

ROSE_LAUNCHER_ULIMIT_OPTS="-a -s unlimited -d unlimited -a"

This is meant to run the following commands:

ulimit -a
ulimit -s unlimited
ulimit -d unlimited
ulimit -a

i.e. show the current settings, change various settings, show the new settings.

Unfortunately the code as it stands results in:

ulimit -a $OPTARG

for ulimit arguments without a value (HSa). Since $OPTARG is not defined in these cases, the set -u in lib/bash/rose_init brings down the script. I believe set -u is a relatively new addition to this script and why this problem has only recently been identified when a user tried to use this capability.

[scwhitehouse]

That looks reasonable to me!