[Users] weird behavior with some ET simulations

[Zach Etienne]

Hi Toni,

The problem you report seems to be related to the AMR, which is a separate
module from Llama. There have been multiple updates to the AMR
infrastructure since 2017.

-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 1:42 PM Antoni Ramos Buades <
antoniramosbuades at gmail.com> wrote:

> 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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