Thermalized MRT LB

See https://i10git.cs.fau.de/software/pystencils/issues/22

Philox-based RNG are now available in pystencils We should discuss now details about the method you need e.g. moment orthogonalization, which moments are perturbed..

I think all the necessary parts (RNG, codegen integration in waLBerla) are available now to implement a custom thermalized LBM. So if @kuron and @winterhalter agree I'd close this issue.

Question is whether this issue should remain open until the thermalized LBM is finished and can be added to the normal methods available by default in walberla.

@bauer, can you please provide a test case/example as tests/lbm/codegen/MrtWithThermalization.cpp and tests/lbm/codegen/MrtWithThermalization.py in Walberla? Once you do that and once https://i10git.cs.fau.de/software/pystencils/merge_requests/37 is merged, I agree that this issue can be closed.

Therefore I'd need to know which moments should be perturbed in which way.. but I think @winterhalter is working on that?

I am working on a general version of the thermalized LBM. Currently on hold while I'm preparing a poster and results for the DPG next week.

We already have it for D3Q19, right? You could just put that specialization into Walberla for now and replace it with the generalization in the 4.1 release.

Its more or less untested/verified though hence still marked as WIP even for the specialized version. I'd argue against putting it in walberla as is. Do you have immediate need in the 4.0 version? If so I'll see whether it would be possible to actually do the generalized version soon.

For Espresso we would want to use a release version. If you promise to do it soon, I'm fine with moving thermalization to a 4.2 milestone though.

changed milestone to %4.2

assigned to @winterhalter and unassigned @bauer

mentioned in issue pycodegen/lbmpy#2 (closed)

mentioned in merge request pycodegen/lbmpy!1 (closed)

mentioned in merge request !220 (merged)

removed milestone

closed via merge request !220 (merged)

mentioned in commit eb1fd933