...

Also, to have an error to actually debug, I set the PGI compiler to 16.10.0 in env_mach_specific.xml.

./case.setup
./case.build

I then changed the "run_exe" value from "${EXEROOT}/acme.exe" to "pgdbg ${EXEROOT}/acme.exe" to have it run the debugger

EXEROOT

On Titan, the EXEROOT is important because while the executable may normally live in NFS file space, if the executable is an argument to a debugger, it must then live in Lustre space. The EXEROOT variable in CIME is currently defaulting to: $CIME_OUTPUT_ROOT/$CASE/bld, which is good because it means that one can change the location of the executable by specifying --output-root in the ./create_newcase command, which makes things much simpler.

Running Interactively

Robert Jacob & James Foucar, any advice on running ACME in an interactive job on Titan with CIME 5.2?