[ET Trac] [Einstein Toolkit] #1239: AHFinderDirect uses incorrect origin_* upon recovery when horizon was never found before

[Einstein Toolkit]

#1239: AHFinderDirect uses incorrect origin_* upon recovery when horizon was never
found before
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 Reporter:  reisswig@…                  |        Type:  defect               
   Status:  new                         |    Priority:  major                
Milestone:                              |   Component:  EinsteinToolkit thorn
  Version:                              |    Keywords:  AHFinderDirect       
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 Problem: After some time in the simulation, I want to search for an
 horizon. I do not know where the horizon appears initially when the
 simulation started. I therefore leave origin_* and
 initial_guess__coord_sphere__*_center at zero.

 By some means later, I have figured out where the horizon will appear.
 Therefore, after recovery, I want to set origin_* and
 initial_guess__coord_sphere__*_center to the origin where I believe the
 horizon will appear.

 Unfortunately, upon recovery, the new origin_* is overwritten by whatever
 was stored in ah_origin_* (this would be zero). Generally, this means that
 the initial guess ellipsoid that is setup when a horizon has never been
 found, is ill-posed (because the initial (and incorrect) origin_* are used
 with the updated initial_guess__coord_sphere__*_center).

 Solution: Don't use the stored AH origin upon recovery when a horizon has
 never been found before.

 The attach patch solves the problem.

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Ticket URL: <https://trac.einsteintoolkit.org/ticket/1239>
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