[ET Trac] [Einstein Toolkit] #380: AHFinderDirect failure with qc0-mclachlan.par

[Einstein Toolkit]

#380: AHFinderDirect failure with qc0-mclachlan.par
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  Reporter:  hinder  |       Owner:            
      Type:  defect  |      Status:  new       
  Priority:  major   |   Milestone:  ET_2011_05
 Component:  Other   |     Version:            
Resolution:          |    Keywords:            
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Comment (by rhaas):

 AHFinder uses this grid function (which is zero outside of the horizon
 non-zero inside and in a buffer zone) to find out if it is using points
 from within the horizon. There is a also a noshrink option to AHFinder
 which prevents horizons from ever shrinking (and uses the mask to detect
 this). From looking at it (had to because this actually caused aborts for
 me at one point) this seems related to excision (expansion.cc line 928).

 I don't think that the mask is required for anything else (in vacuum, it
 is very useful to have around for hydro).

 The mask is used all the time not just during initialization so I cannot
 turn it off. I wanted to say that there are two issues: ahmask usage
 during evolution where you can set find_every = coarsest_step and the one
 during initialization where find_every will not help.

 I am happy with whatever solution is decided upon. I just looked at
 AHFinder's schedule.ccl and it already allocates several timelevels based
 on a parameter: ADMBase::metric_timelevels So setting this to 3 should
 solve the issue in a nice way.

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Ticket URL: <https://trac.einsteintoolkit.org/ticket/380#comment:6>
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