Set run length

Controlling the length of a submission using the XML variables

The length of a simulation that is performed within one submission is set in the env_run.xml file with the variables STOP_N and STOP_OPTION. STOP_OPTION controls the units in which you are specifying the length of the simulation and STOP_N is the length in those units.

By default, the model is set to run for 5 days with

STOP_N = 5
STOP_OPTION = ndays

You can query the default settings of these variables with the command xmlquery from inside your case directory e.g.,

./xmlquery STOP_OPTION,STOP_N

will print out the values of STOP_OPTION and STOP_N.

You can change the values of these parameters using the xmlchange command. For example, suppose you want to increase the run length from 5 days to 1 month, you can use:

./xmlchange STOP_OPTION=nmonths,STOP_N=1

The variables STOP_OPTION and STOP_N control the length of one run segment. Typically supercomputers have limits on how long you can run at once e.g., some may have a wallclock limit of 12 hours in real time, meaning that you can only run continuously for 12 hours. In that case, you would want to set STOP_OPTION and STOP_N to an appropriate length that can be completed within 12 hours of real time.

More information about the other variables in env_run.xml can be found here.