WhatIs: The run.def input file

About the run.def input file, its format and included def files

The run.def file is a text file that is read at run time by LMDZ (and must thus be present in the same directory as the executable). It contains the values of various parameters that the user can specify (as "key = value", where "key" is a predefined keyword and "value" may be a real, an integer, a string or a logical) and modify depending on the specific simulation that is intended, e.g. the line:

nday = 30

means that when the GCM will run, it will set parameter nday (the number of days to run) to 30.

Any line starting with # is a comment, e.g.

# nday : length of the simulation (in days)

The order in which parameters are given in the run.def file is not important, except if a parameter value is given more than once (not recommended!), then it is the last occurrence that prevails.

The run.def file can include other files (based on the same format, lines containing "key = value" or comments) using the INCLUDEDEF keyword, e.g.:

INCLUDEDEF=gcm.def

In practice, because there are many parameters that one can set/change, it is good practice to separate related sets of parameters in separate files.

Reference *.def files are provided in the LMDZ/DefLists directory

12/05/2020