[Users] weird behavior with some ET simulations

[Antoni Ramos Buades]

Hi,

we are using a version of the EinsteinToolkit of 2017, particularly,

!DEFINE ET_RELEASE = ET_2017_06

so it is not one of the newest versions, but as far as I know in the last
releases there has not been updates on the Llama thorn. Although we can try
to run with older or newer versions if you think it can help to solve the
problem.

Best Regards,
Toni.


El mié., 6 mar. 2019 a las 18:29, Zach Etienne (<zachetie at gmail.com>)
escribió:

> Hi Antoni,
>
> This is a worrisome finding, thanks for sharing. It would be useful if you
> would let us know what version of the ET you are using. Further, if you
> could attempt the simulation with earlier versions of the ET (e.g., the
> first version with Llama included), it would help to determine if this
> issue arose due to some recent commit.
>
> -Zach
>
> *     *     *
> Zachariah Etienne
> Assistant Professor of Mathematics
> West Virginia University
> *https://math.wvu.edu/~zetienne/ <https://math.wvu.edu/~zetienne/>*
> https://blackholesathome.net
>
>
> On Wed, Mar 6, 2019 at 9:40 AM Antoni Ramos Buades <
> antoniramosbuades at gmail.com> wrote:
>
>> Hi,
>>
>> my name is Antoni Ramos Buades, I am PhD student in the University of the
>> Balearic Islands working with Sascha Husa. We have been using ET with the
>> Llama thorn to produce waveforms. We have observed in some simulations
>> strange behaviors in the waveforms. For example, I have attached a plot of
>> the amplitude of the psi4 of a non-spinning q1 simulation, for different
>> higher order modes, where you can see that the 22, 32 and 44 show weird
>> spikes. We have rerun this simulation outputting 2D data in the x-y plane.
>> We have plotted the Hamiltonian constraint and made a movie (I cannot
>> attach the movie because its size is 42Mb ) but I can attach some snapshots
>> where you can observe that there seems to be an outburst of noise when the
>> boxes are aligned, and this continues happening in the simulation each time
>> the boxes are aligned with each other. Geraint Pratten is also
>> investigating this issue  adding some new parameters in the parameter file
>> (attached to the email) for the carpet mesh refinement like
>> freeze_unaligned_parent_levels, freeze_unaligned_levels, ... and running
>> some tests.
>>
>> We would like to ask you if somebidy has ever seen this thing happening
>> before and if somebody knows how one could solve this problem, because with
>> the same Carpet settings we have observed that for some configurations
>> (mass ratio and spins) this does not happen, but for others, like the one
>> presented in this email we do. I have additional quantities as a 2D output
>> like the curvature, metric, horizon, ... in case you think they could be
>> used to check something.
>>
>> Thanks and best regards,
>> Toni.
>> _______________________________________________
>> Users mailing list
>> Users at einsteintoolkit.org
>> http://lists.einsteintoolkit.org/mailman/listinfo/users
>>
>
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