[Developers] [Patches] ADMConstraints: Recompute constraints after regridding and restricting

Frank Loeffler knarf at cct.lsu.edu
Tue Dec 8 14:48:35 CST 2009


Hi,

On Tue, Dec 08, 2009 at 02:11:58PM -0600, Erik Schnetter wrote:
> These changes only modify the behaviour if constraints_persist is set to true.  In this case, the constraints are supposed to be treated like an evolved variable, and are supposed to be either evaluated after each substep (in MoL_PostStep) or in EVOL after MoL_Evolution.  In particular, the coarse-grid constraints are then supposed to be restricted from finer grids, same as an evolved variable.

I didn't think of this when I commited the patch. I was thinking this
way: the ADMConstraints are an analysis quantity. They depend on
derivatives, so the restricted value will often be different from the
value which would be obtained by recomputing on the coarse timelevel.

Since the ADMConstraints are 'only' an analysis quantity, one might as
well be interested in their values on coarse refinement levels but
within a domain which is also covered by a finer grid (which would hold
the values on that grid).

Now the question would be: what should we expect this quantity to be on
coarser levels within a domain which is also covered by a finer level?
Both options sound reasonable to me, and I don't really need one or the
other myself.

Frank

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