[ET Trac] [Einstein Toolkit] #558: Carpet with Periodic Boundary Conditions

[Einstein Toolkit]

#558: Carpet with Periodic Boundary Conditions
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  Reporter:  hfinkel@…        |       Owner:  eschnett       
      Type:  enhancement      |      Status:  reopened       
  Priority:  major            |   Milestone:                 
 Component:  Carpet           |     Version:                 
Resolution:                   |    Keywords:  carpet periodic
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Comment (by bentivegna):

 I've looked into this in more depth and I've found at least two major
 issues that prevent the original setup from working correctly:

 1) Slab (used by Periodic for filling the symmetry boundaries) doesn't
 seem to work when moving data between two components of the grid that are
 owned by the same process (this is also stated in the documentation); as a
 result, when a refinement level is split into two components (as would
 have to be the case for one that overflows on one side of the domain and
 has a chuck appearing on the opposite face) and they are both handled by
 the same process, the boundaries are simply not filled. If these points
 existed when the initial data was set, they keep those values forever. If
 the refinement appears later, it will contain poison. This problem can be
 reproduced with ks-mclachlan.par, and I'll create a new ticket for Slab;
 2) The original example also tries using true AMR. I'm quite unfamiliar on
 how this should be done, and would like to understand exactly at which
 point the level_mask needs to be set. With the current location
 (preregrid), the grid structure will be different depending on whether
 poisoning is used, which seems to point out that something is used before
 the user thorn has the chance to set it. Notice that the question is
 complicated by the fact that the level_mask is set from a derivative of a
 grid function, so that it will take a few operations (interior loop,
 syncs, boundary conditions, …) to fill the whole domain with the correct
 values. The ET list is probably a good place for this discussion.

 Regarding the original request of making Carpet aware of periodic
 boundaries, as far as I can test Erik's third patch works and closes this
 ticket.

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Ticket URL: <https://trac.einsteintoolkit.org/ticket/558#comment:23>
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