Mesh Partitioning Changes Bottom Depth

[alxthor]

There are indications that partitioning the mesh can change elvls.out and nlvls.out (I hope I am interpreting the content of these files correctly). Is this behaviour expected?

In particular, before partitioning dist_384 in /work/ab0246/a270092/input/fesom2/for_alex/core2 on Levante, nodes 125226 and 125228 had depths of 18 and 19, respectively. After partitioning it got deeper (22 resp. 20).

This can lead to unexpected blowups of simulations which used to work fine before, if in the mean time an additional mesh partitioning is generated. Changing those values back to the original ones bitidentically reproduces output from before generating the partitioning.

Below is the diff output. It is an interesting coincidence that the change in depth occurs at element number 1.

---

Diff on nlvls.out:

125226c125226
<           22
---
>           18
125228c125228
<           20
---
>           19

Diff on elvls.out:

1c1
<           22
---
>           18
187115c187115
<           20
---
>           18
187171c187171
<           22
---
>           18
241598c241598
<           20
---
>           19

[patrickscholz]

@alxthor : Das sollte eigentlich nicht passieren! Mir würde spontan auch nicht einfallen warum das der Fall sein sollte, da nlvls.out und elvls.out alles globale arrays sind und die Partitionierung läuft seriell und die ganzen Partionierungssachen laufen erst nachdem die ganzen nlvls.out, elvls.out ... schon rausgeschrieben sind! Ist das konsistent reproduzierbar?

[alxthor]

The problem is reproducible. I made a new clone of the fesom main branch (23f52be), compiled the mesh partitioner, and ran it. It overwrites nlvls.out and elvls.out in the mesh path I provide.

If one restores the original nlvls.out and elvls.out and reruns the partitioner, again these files are overwritten in the same way.

During tests I also noticed that the partitioner crashes, if there is no write access to edgenum.out

[patrickscholz]

Das er die Files überschreibt ist prinzipiell OK, aber er muss sie identisch überschreiben unabhängig davon für wieviele Partitionen du hast !!! Und das der partitioner crashed, is prinzipiell auch OK da wir bis jetzt nicht checken ob er schreiben darf oder nicht und wenn er nicht schreiben darf steigt er natürlich aus.