[aspect-devel] Weird pressure with periodic BC's + direct solver?

[Wolfgang Bangerth]

Jonathan,

> I just noticed that a bunch of models I've run recently have strange
> pressure fields (see attached). It only happens with a periodic boundary
> condition, and the direct solver enabled at the same time. Any other
> combination of one or the other setting doesn't do this.
> 
> The velocity fields look correct (as compared to models with direct
> solver turned off), so *hopefully* this is somehow just a
> post-processing problem. Anyone have insight here?

It looks like the problems are all located along specific lines. Is this where 
processor boundaries lie? Or hanging nodes? Can you produce the same picture 
with the mesh overlaid?

I'm wondering whether we properly call ConstraintMatrix::distribute() on the 
solution vector after calling the direct solver. This would explain artifacts 
at hanging nodes.

Best
  W.

-- 
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Wolfgang Bangerth          email:                 bangerth at colostate.edu
                            www: http://www.math.colostate.edu/~bangerth/