CFD Online Discussion Forums - Continue OpenFoam parallel run with different number of processors

CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)

- OpenFOAM Running, Solving & CFD (https://www.cfd-online.com/Forums/openfoam-solving/)

- - Continue OpenFoam parallel run with different number of processors (https://www.cfd-online.com/Forums/openfoam-solving/237951-continue-openfoam-parallel-run-different-number-processors.html)

Continue OpenFoam parallel run with different number of processors

Hi all. I am running a large case on a cluster. I have a job completed on 16 cores up to a timestep of 10000s. I have reconstructed the data using reconstructPar and deleted all the processor directories (processor0, processor1...).

How do I continue the job to a timestep of 20000s using 32 cores instead?

This is my script:

Code:

decomposePar -force

mpirun -np 16 renumberMesh -overwrite -parallel

mpirun -np 16 overPimpleDyMFoam -parallel | tee log.solver

I have edited the controlDict to start from the latestTime and the decomposeParDict has been changed for 32 processors now. After the decomposePar command, do I need to renumber the mesh again with 32 cores before running the solver itself?

From a quick look at the source code (https://github.com/OpenFOAM/OpenFOAM...renumberMesh.C), I don't see any reference to the number of processors in the run in the coding, so I don't think that the way you have decomposed the problem matters. Instead, the utility is used to make the LDU matrix addressing more efficient - see eg this post.

Great, just needed some confirmation before submitting the job. Thank you!