[Users] ADMConstraints

[Bela Szilagyi]

Given the scheduling of MoL_PostStep in postregrid (and the scheduling of many 
boundary routines affecting ADM variables in MoL_PostStep), I believe, we 
need to schedule the adm constraints computing group in postregrid AFTER 
MOL_POSTSTEP.

That is,

if (constraints_persist)
{
 ...

  schedule GROUP ADMConstraintsGroup at CCTK_POSTREGRID after MoL_PostStep
  {
  } "Evaluate ADM constraints, and perform symmetry boundary conditions"

}




On Thursday 31 May 2007 03:58:46 Erik Schnetter wrote:
> While calculating the constraints with ADMConstraints in the presence
> of mesh refinement works fine, there was a problem with calculating
> norms of the constraints, which may require time interpolation.  In
> order to do this correctly, it is necessary to keep several time
> levels of the constraints, and to re-calculate the constraints after
> changing the grid hierarchy.  If this is not done, then the values of
> the constraints at each output grid point are correct, but norms of
> the constraints may not be.
>
> I updated ADMConstraints so that it supports this behaviour.  In
> order to remain backward compatible, this behaviour cannot be the
> default.  Obtaining correct norms for the constraints requires
> setting the parameters
>
> ADMConstraints::constraints_persist = yes
> ADMConstraints::constraints_timelevels = 3
>
> where the number 3 depend on the time interpolation order; for linear
> time interpolation, you only need 2 time levels.
>
> On the other hand, if you want to save space and time, and if you do
> not need the norms of the constraints, then you should set the parameter
>
> ADMConstraints::constraints_prolongation_type = "none"
>
> -erik





Bela Szilagyi
----------------------------------------------------
Max-Planck-Institut für Gravitationsphysik
Albert-Einstein-Institut
Tel: +49 331 567 7189
Fax: +49 331 567 7252
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