[Users] Meeting minutes for 2026-03-05

[Miguel Zilhão]

hi Steve,

> We did look at it, but no one has had a chance to research what might be
> going wrong so far.
> 
> Is there a problem if the black hole is uncharged?
> 

this issue is clearly noticeable in the violation of the electric (or 
Gauss) constraint. if the black hole is uncharged, this quantity is 
trivially zero... so, in that sense, there is no (obvious) problem.

however, i do think that the problem is also there for computations of 
the Hamiltonian constraint (even for uncharged BHs). one does see noise 
propagating out of the buffer zones when subcycling in time in such 
cases as well, but in those cases it doesn't seem to spoil convergence. 
whereas in the charged case, for the electric constraint, convergence is 
totally lost.

thanks,
Miguel


> On 3/5/2026 1:45 PM, Miguel Zilhão via Users wrote:
>> i couldn't take part in the call, but just to recall that there is
>> also the open ticket 2920:
>> https://bitbucket.org/einsteintoolkit/tickets/issues/2920/loss-of- 
>> convergence-with-subcycling-in
>>
>>
>> On 05/03/2026 15:54, Steven Brandt via Users wrote:
>>>
>>> Present: Roland, Steve, Peter, Keith, Maxwell Rizzo, Rahime Matur,
>>> Nikolai, Cheng-Hsin, Zach, Lucas
>>> Chair: Roland
>>> Minutes: Steve
>>>
>>> Release:
>>>      - It's time to regenerate the thorns. We should do it ASAP.
>>> Beyhan will attempt to run them.
>>>      - Are we still using AutoConf2.13? No. Roland will update the
>>> Release Process for AutoConf.
>>>      - Add Boost to the release details (Boost has to be 84 or less)
>>>      - Time to start testing, driving reviews, etc.
>>>      - Roland is linking the testing process
>>>      - CapyrX: Lucas says that it now has continuous integration
>>> tests in its repo, based on CarpetX tests. Roland asks to add it to
>>> the manifest.
>>>      - CanudaX: Cheng-Hsin says not much updates. Roland asks to add
>>> it to the manifest.
>>>      - BHaHaHa: Zach says its updated to the latest NRPy and latest
>>> toolkit and added to the manifest.
>>>      - BHNS Gallery Example: Sumbit paper to Archive this week.
>>> Create thumbnail and web page.
>>>      - Boost: Roland is the champion.
>>>      - Cottonmouth: We'll get into the manifest soon.
>>>      - Add Machine: DIRAC/Cosma's simfactory files (Rahime)
>>>
>>> RK4 paper has been formally accepted.
>>>
>>> Questions on the mailing list:
>>>      Strange failures on setting parameters
>>>      Can he had Deucalion to Simfactory
>>>
>>> CarpetX cannot compile with the latest CUDA.
>>>
>>> Open tickets by update time:
>>> 2910: Add option to exclude 1d boundaries.
>>> 2921: Lucas: Use boundary conditions with Multipatch.
>>> 2908: Will poke Max
>>> 2909: Remove tags
>>> 2898: Waiting for review.
>>> 2912: Inconsistent computation of volume
>>> 2855: NoiseX - may use hash of coordinate value instead of random
>>> number generator
>>> 2814: TensortypeAlias - Maybe obsoleted by 2909
>>>
>>>
>>> Gravitation/cannot/be held responsible for/people falling in love --
>>> Einstein/
>>>
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