Ghost translation #1006
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Ghost translation #1006
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…is at higher refinement level instead of continuing over VLASOV_STENCIL_WIDTH
… based on Yann's feedback
…arbee/vlasiator-public into AMR_translation_optimizations
Also stupidly hardcoded debug output.
Extra padding is no longer required, since dccrg is now behaving much more sanely wrt. neighbors.
ykempf
reviewed
Aug 22, 2024
ykempf
reviewed
Aug 22, 2024
…scaling with ghost translation extent). Commented-out code for limited remote neighbour list updates.
…memory issues on restart
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Replaces #609
Incorporates #1000
This PR introduces ghost translation (previously known as local translation). Allows for running all Vlasov translation with coalesced MPI just before the actual call, reducing the overhead related to 3D imbalances. This comes at the cost of having to actually compute translation for a boundary of ghost cells. This also requries a grid neighborhood of VLASOV_STENCIL_WIDTH+1 which does incur some overhead.
Turn on ghost translation with
vlasovsolver.GhostTranslateset to true. This current form of the PR forces this on so we get CI with it active, but it should probably be turned off as default.The correctness of this method was validated with local tests but this PR should re-confirm it with CI. If so preferred, a smaller ghost neighbourhood can be translated instead of all required, resulting in some diffs at process boundaries, but less of an overhead. This might be useful for example for early flushing of a simulation. The size of the stencil to include in ghost translation can be set with
vlasovsolver.GhostTranslateExtent. The parameter has a default of0which is automatically replaced withVLASOV_STENCIL_WIDTH+1. Values greater than that are capped. Thus, possible values are between1andVLASOV_STENCIL_WIDTH+1.