Nesting

A multi-scale nesting system is available since rXXXX. It currently undergoes major testing and revisions. A detailed description will follow after the official release.

Job preparation

The following example provide a step-by-step tutorial on how to set up a nesting system with one parent (root) domain and two child domains.

1. Prepare parameter files for all domains, e.g. for run with topography and separate topography data for each domain:

   testrun_p3d (root/parent domain)
   testrun_01_p3d (child domain 1)
   testrun_02_p3d (child domain 2)
   testrun_topo
   testrun_01_topo
   testrun_02_topo
   

2. The nesting system is activated by specifying a &nestpar NAMELIST in the _p3d file of the root domain, e.g.:

    &nestpar domain_layouts = 'root domain',      1,  -1,  24,    0.0,    0.0,
                              'child domain 1',   2,   1,  24,  100.0,  100.0,
                              'child domain 2',   3,   1,  24,  200.0,  200.0,
             nesting_datatransfer_mode = 'mixed',
             nesting_mode = 'two-way',
   /
   

For details on the parameters, see nestpar.

3. Add file connection statements for all child domains to the .mrun.config file,

   #----------------------------------------------------------------------------
   # List of input-files for nested model runs
   #----------------------------------------------------------------------------
   PARIN_01                  in:job        nest#      $base_data/$fname/INPUT   _01_p3d
   PARIN_02                  in:job        nest#      $base_data/$fname/INPUT   _02_p3d
   TOPOGRAPHY_DATA_01        in:locopt     nest#      $base_data/$fname/INPUT   _01_topo
   TOPOGRAPHY_DATA_02        in:locopt     nest#      $base_data/$fname/INPUT   _02_topo
   

4. Execute mrun and specify the nesting input files, i.e.,

   mrun -d testrun -r "d3# nest# ts# pr# ..." -X "72" ...
   

Make sure that the total number of PEs (here 72) the sum of the PEs allocated for the individual domains (3 x 24).