[Users] Fwd: SphericalSurfaces + QuasiLocalMeasures + AHFinderDirect

[Erik Schnetter]

Leonardo

In this case the initial guess for the horizon radius might be off. As a
rule of thumb, the surface where \alpha = 0.3 is the horizon. Your guess of
r = 1 might be off.

-erik


On Wed, Jun 28, 2023 at 4:58 PM Leonardo Werneck <wernecklr at gmail.com>
wrote:

> He Erik,
>
> Thanks for the response!
>
> The puncture is placed at x=5 because of the nature of the grid used by
> the elliptic solver. However, when the solution is interpolated to the
> carpet grid the position of the puncture is shifted to x=0 (this is
> controlled by the parameter NRPyEllipticET::position_shift[0]; please see
> the attached plot of the lapse function at t=0).
>
> Cheers,
> Leo
>
> [image: image.png]
>
>
>
> On Wed, Jun 28, 2023 at 1:49 PM Erik Schnetter <schnetter at gmail.com>
> wrote:
>
>> Leonardo
>>
>> I've briefly looked at the parameter file. The horizon finder needs to
>> know an initial guess for both position and shape of the horizon. You
>> are setting this location to 0, but are placing the puncture at x=5.
>> The horizon finder then fails. QuasiLocalMeasures then sees that there
>> is no horizon and does not run.
>>
>> -erik
>>
>> On Wed, Jun 28, 2023 at 3:50 PM Leonardo Werneck <wernecklr at gmail.com>
>> wrote:
>> >
>> > Dear all,
>> >
>> > I am trying to create a simple parfile to help a PhD student. The goal
>> is to set up puncture initial data with NRPyEllipticET and then use
>> QuasiLocalMeasures/AHFinderDirect to compute properties of the punctures
>> and compare with the expected results. No evolution thorn is
>> expected/required and the simulation ends after the initial data has been
>> set and the first round of analysis has finished.
>> >
>> > The parfile attached partially works. The puncture initial data is set
>> up and NRPyEllipticET's output is what I'd expect. However, the diagnostics
>> are clearly wrong since: 1) AHFinderDirect fails to find the puncture (in
>> this example I am setting the mass of one of the punctures to zero); and 2)
>> the QuasiLocalMeasures diagnostics is never triggered, despite being
>> scheduled.
>> >
>> > Could someone provide some guidance on how to set up these thorns
>> correctly, specifically SphericalSurfaces, QuasiLocalMeasures, and
>> AHFinderDirect? Am I missing additional thorns?
>> >
>> > Also, if someone has a working TwoPuncture example parfile instead,
>> please share it with me as I'd be happy to adapt it!
>> >
>> > Thanks in advance!
>> > Leo
>> >
>> > --
>> > ------------------------------
>> > Dr. Leonardo R. Werneck, Ph.D.
>> > _______________________________________________
>> > Users mailing list
>> > Users at einsteintoolkit.org
>> > http://lists.einsteintoolkit.org/mailman/listinfo/users
>>
>>
>>
>> --
>> Erik Schnetter <schnetter at gmail.com>
>> http://www.perimeterinstitute.ca/personal/eschnetter/
>>
>

-- 
Erik Schnetter <schnetter at gmail.com>
http://www.perimeterinstitute.ca/personal/eschnetter/
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