Set run length

Controlling the length of a submission using the XML variables

The length of a simulation that is performed within a single 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

This command 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

Keep in mind that the variables STOP_OPTION and STOP_N control the length of one run submission and the length of the full simulation. Typically supercomputers have limits on how long you can run at once. For instance, some supercomputers 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.