What variables are available for output

[jornbr]

[based on a question asked during a fabm-os workshop]

How can I see what variables are available for output and therefore can be specified by name in <OUTPUTFILE>.request(...)?

[jornbr]

The best way is to (temporarily) customize your run script to print a list of all available variables to screen. The following line does this for all state and diagnostic variables that your chosen biogeochemical model makes available by default:

print([v.name for v in sim.fabm.default_outputs])

Or slightly prettier:

for v in sorted(sim.fabm.default_outputs, key=lambda v: v.name):
    print(f"{v.name}: {v.long_name} ({v.units})")

The following shows all available variables including internally used ones that are typically hidden from output:

print(domain.fields.keys())

but this typically shows so many variables to become overwhelming.

Either of these lines can be inserted directly after you create your Simulation (typically called sim). You may want to follow your print line with sys.exit(0) to just get the available variables and not start a simulation. You'll probably wan to run in serial for this specific purpose, i.e., with python <RUNSCRIPT> instead of mpiexec -n <NCPUS> python <RUNSCRIPT>.

For completeness: if you provide an unknown variable name to <OUTPUTFILE>.request, it will complain and show all available variables itself as part of the error message. And you can potentially also diagnose which variables are available by running a short while saving everything, i.e., with <OUTPUTFILE>.request(*sim.fabm.default_outputs)