exact wall distance uses existing decomposition method

Summary

'exact' wall distance in parallel uses the decomposition method in system/decomposeParDict. If this is set to a topological method it might behave very badly if the processors cannot be represented by bounding boxes.

Steps to reproduce

Swithc on the debug flag for distributedTriSurfacMesh and look out for the individual bounding boxes of the processors. You want to avoid that any processor encapsulates all of the global bounding box (since it would cause all queries to be sent to it)

Example case

What is the current bug behaviour?

What is the expected correct behavior?

Relevant logs and/or images

Environment information

OpenFOAM version : 1906 Operating system : Compiler :

Possible fixes

The solution is to use hierarchical. The problem is how to automatically set it up if the user e.g. is running with scotch:

• what should be the individual splits (nx ny nz)?
• what if the number of processors cannot be decomposed into factors (e.g. it is a prime)