[v.4.0.x] Restarting from single file with different processor numbers stops at first time step

Versions v4.0.x
1

Hi,
I use XIOS (v2.5) to create a single restart file (nn_wxios=1). When I use the restart file, the subsequent model run fails at first time step itself if there is a change in nemo processor number than the first run. Seems something related to the domain decomposition/land processor elimination. Is there any fix for this!

Thanks
Bijoy

2

Hei Bijoy,

Non-used processors are given a NaN value for all fields, when you will use the single restart there is a big chance that some NaN will end up on a computing domain, which even if masked will inject some NaN in the computation (since 0 times NaN equals NaN) and make the model crash.
If you run some tool (like nco or cdo) to eliminate NaN on the restart file before you run then this usually solves the issue. At least it was my experience.

Hope this helps,

Robinson

3

And I forgot, this happens because of the change of processor map which makes some data with NaN can fall on the computing domain…