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Créée par
Winger, Katja, dernière mise à jour le déc. 04, 2025
2 min de lecture
There are several restrictions as to the number of MPI tiles that can get used for a given grid. Small numbers of MPI tiles usually work, but the more MPI tiles one would like to use the more restrictions there are. Using an MPI tiling which is not allowed causes the model to crash. But since it often takes quite some time for large surface jobs to start running, you might want to use the following tool to get a list of allowed and recommended MPI tiling.
The script will list all possible values to set 'GEM_ptopo' within a certain range and also give recommendations as to which tilings are most efficient.
The main script is called "findtopo" and is currently available on the internal servers of the ESCER Center as well as on Rorqual.
The script will execute part of the GEM model, so it needs the model environment!
Usage
To use the tool one first has to:
- Go into the directory which contains the file 'gem_settings.nml'.
- Set the model environment with, for example:
511 - Execute the script with:
findtopo
When on the UQAM servers make sure you are using this script: /envi/RPN_tools/bin/findtopo!!!
Input keys
The script accepts the following input keys:
| Key | Description |
|---|---|
| gemnml | Name of namelist file; default: 'gem_settings.nml' |
| minx | Minimum number of tiles to use in x-direction; default: 8 |
| miny | Minimum number of tiles to use in y-direction; default: 8 |
| mincores | Minimum number of total cores to be used; default: 192 |
| maxcores | Maximum number of total cores to be used; default: 1152 |
| corespernode | Number of cores per node; default: 192 |
| maxwaste | Maximum number of cores that can get wasted; default 0 |
| mintilex | Minimum number of points per tile in x-direction; default: 20 |
| mintiley | Minimum number of points per tile in y-direction; default: 20 |