[Users] Excision with McLachlan

[Peter Diener]

Hi Miguel,

Here's a bit more information. There is no support in McLachlan for 
using LegoExcision. LegoExcision was used with an old implementation of 
BSSN. As Jonah said, when using Llama, it's possible to do excision
by using a six-patch coordinate setup. In principle it is also possible
to use a patch system with 13 patches to have 2 spherical exicision 
regions. However, there is no infrastructure for keeping 2 black holes
centered on the excision regions as the system starts to evolve. Hence,
you'll encounter the problem that the black holes will move and the 
excision regions will eventually cross the horizon at which point your 
simulation will crash.

To perform simulations a lot of infrastructure (a la what is available 
in SpEC) to control the shape and size of the horizons during a 
dynamical evolution.

Cheers,

   Peter

On Monday 2017-03-27 09:59, Jonah Miller wrote:

>Date: Mon, 27 Mar 2017 09:59:51
>From: Jonah Miller <jonah.maxwell.miller at gmail.com>
>To: users at einsteintoolkit.org
>Subject: Re: [Users] Excision with McLachlan
>
> Hi Miguel,
>
> I'm not sure about excising dynamically during evolution--maybe someone else 
> has insight there. However, excision is definitely possible. I have been using 
> the sixpatches Llama thorn to perform excision for a single black hole. I 
> attach a parameter file to excise a Kerr-Schild black hole that I based my 
> simulations on.
>
> Best,
>
> Jonah
>
>
> On 2017-03-27 05:01 AM, Miguel Zilhão wrote:
>> hi all,
>> 
>> i was wondering whether one could straightforwardly use the ET to perform 
>> black hole
>> evolutions using excision instead of punctures.
>> 
>> specifically, i had in mind a collapsing configuration where i'd like to 
>> excise the inner
>> domain once a black hole horizon is formed... is this possible?
>> i had a look around and noticed the LegoExcision thorn, but i'm not sure 
>> whether it's
>> actively maintained, nor whether it can interface with McLachlan...
>> 
>> thanks,
>> Miguel
>> _______________________________________________
>> Users mailing list
>> Users at einsteintoolkit.org
>> http://lists.einsteintoolkit.org/mailman/listinfo/users
>
>