[Users] Einstein Toolkit Meeting Reminder

[reminders]

Hello,

Please consider joining the weekly Einstein Toolkit phone call at
8:30 am US central time on Thursdays. For details on how to connect
and what agenda items are to be discussed, use the link below.

https://docs.einsteintoolkit.org/et-docs/Main_Page#Weekly_Users_Call

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Re: [Users] how to review a contribution guideline

[Roland Haas]

Hello all,

I added "ask for a gallery example" as an optional requirement to the
draft:

https://docs.einsteintoolkit.org/et-docs/How_to_Review_a_new_component#Optional_criteria

Yours,
Roland

> Gabriele
> 
> This is an excellent idea.
> 
> My usual criteria would be:
> - needs to have a "getting started" document
> - needs to have example output that can be reproduced
> A gallery example implies both.
> 
> -erik
> 
> 
> On Tue, Aug 2, 2022 at 11:17 AM Roland Haas  wrote:
> >
> > Hello all,
> >
> > Since I am serving as release manager for the upcoming release and
> > could not find this information collated in a single location I started
> > to draft a reviewer's guide for contributions (slightly different from
> > the how to review a patch guide
> > https://urldefense.com/v3/__https://docs.einsteintoolkit.org/et-docs/How_to_Review_a_Patch__;!!DZ3fjg!5ShQVlCnpQncjV3BkINCorG82NQQcVd8jgWedRB-dyWZphwW_w_jJ7I3rKWoX5qjpT1RdQ08lFXlJYTnwA$
> >   that
> > already existed):
> >
> > https://urldefense.com/v3/__https://docs.einsteintoolkit.org/et-docs/How_to_Review_a_new_component__;!!DZ3fjg!5ShQVlCnpQncjV3BkINCorG82NQQcVd8jgWedRB-dyWZphwW_w_jJ7I3rKWoX5qjpT1RdQ08lFWSGztzbg$
> >  
> >
> > Comments and contributions (you may have to send email first to have an
> > account on the wiki created) would be very welcome.
> >
> > Yours,
> > Roland
> >
> > --
> > My email is as private as my paper mail. I therefore support encrypting
> > and signing email messages. Get my PGP key from 
> > https://urldefense.com/v3/__http://pgp.mit.edu__;!!DZ3fjg!5ShQVlCnpQncjV3BkINCorG82NQQcVd8jgWedRB-dyWZphwW_w_jJ7I3rKWoX5qjpT1RdQ08lFUP_CFcBA$
> >   .
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> >
> 
> 
> 

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Re: [Users] Large junk radiation

[Roland Haas]

Hello Deborah, all,

Having used both TwoPunctures codes in the past: have you eg dumped the
TP coefficients of both codes to disk after a solve to compare those?
The two may have quite different ways of specifying the mass (e.g. one
can hunt for a given mass on its own, the other uses Baum). 

The quantities to output for comparison would be the v.d0 array in
src/TwoPunctures.c .

Yours,
Roland

> Hi Deborah,
> 
> I'd be curious to see a comparison between the junk radiation you're seeing
> now versus before, for the same physical scenario, grids, etc. Also, the
> extra wiggles/reflections are typically caused not by junk radiation but by
> a sharp gauge feature 
> (https://urldefense.com/v3/__https://arxiv.org/abs/1404.6523__;!!DZ3fjg!8pjNitnVpXn7nbD_Tme73cqSxTqjQfOnBdRnCOoyJTvMp2TaJ5yo1xC_AGTLCz8Gquvy97cfTlFcZ6y2$
>  ). The two can be
> easily distinguished as the former propagates at c, and the latter at
> sqrt(2) c (see paper for details).
> 
> -Zach
> 
> * * *
> Zachariah Etienne
> Assoc. Prof. of Physics, U. of Idaho
> Adjunct Assoc. Prof. of Physics & Astronomy, West Virginia U.
> https://urldefense.com/v3/__https://etienneresearch.com__;!!DZ3fjg!8pjNitnVpXn7nbD_Tme73cqSxTqjQfOnBdRnCOoyJTvMp2TaJ5yo1xC_AGTLCz8Gquvy97cfTjyWM0m7$
>  
> https://urldefense.com/v3/__https://blackholesathome.net__;!!DZ3fjg!8pjNitnVpXn7nbD_Tme73cqSxTqjQfOnBdRnCOoyJTvMp2TaJ5yo1xC_AGTLCz8Gquvy97cfTpa-uABN$
>  
> 
> 
> On Tue, Aug 9, 2022 at 4:41 PM Erik Schnetter  wrote:
> 
> > Deborah
> >
> > One one hand, TwoPunctures has parameters to choose the resolution of
> > the spectral grid it uses. I assume you are aware of these, and that
> > you also know how to choose the 3D AMR grid setup parameters.
> >
> > TwoPunctures only solves for the conformal factor. It does per se not
> > directly choose a lapse and a shift, but their choice is important in
> > practice. Choosing \alpha=1 and \beta^i=0 as initial conditions is
> > often not good. Similarly, choosing the antisymmetry lapse (with
> > \alpha=-1 at the puncture) is also a bad idea (it is ill-posed). The
> > TwoPunctures toolkit in the Einstein Toolkit has several options for
> > choosing the initial gauge conditions. Personally, I am partial to
> > initial_lapse = "twopunctures-averaged", but I am sure that others
> > have other preferences.
> >
> > Of course, the BSSN gauge parameters used during evolution will also
> > play a role.
> >
> > You can look at the gallery example at
> >  >  > for ideas.
> >
> > -erik
> >
> >
> >
> > On Tue, Aug 9, 2022 at 4:47 PM Ferguson, Deborah
> >  wrote:  
> > >
> > > Hi,
> > >
> > >
> > >
> > > We had been using our own version of TwoPunctures, and I’ve recently  
> > switched to the ETK version since it doesn’t require solving for the masses
> > separately. Junk radiation has always been present, but I’m finding that
> > some of my recent simulations have particularly loud junk radiation, which
> > also makes it harder avoid reflection of. So I’m guessing I’m not fully
> > understanding the TwoPunctures parameters.  
> > >
> > >
> > >
> > > I’ve attached a parfile and a psi4 plot for a simulation I’ve started  
> > that’s having this large junk radiation, and was hoping someone could point
> > out any mistakes I may have in the TwoPunctures parameters.  
> > >
> > >
> > >
> > > Thanks!
> > >
> > > Deborah
> > >
> > >
> > >
> > > --
> > >
> > > Deborah Ferguson
> > >
> > > Post Doc
> > >
> > > University of Texas at Austin
> > >
> > > ___
> > > Users mailing list
> > > Users@einsteintoolkit.org
> > > https://urldefense.com/v3/__http://lists.einsteintoolkit.org/mailman/listinfo/users__;!!DZ3fjg!8pjNitnVpXn7nbD_Tme73cqSxTqjQfOnBdRnCOoyJTvMp2TaJ5yo1xC_AGTLCz8Gquvy97cfTujfEcn8$
> > >
> >
> >
> >
> > --
> > Erik Schnetter 
> > https://urldefense.com/v3/__http://www.perimeterinstitute.ca/personal/eschnetter/__;!!DZ3fjg!8pjNitnVpXn7nbD_Tme73cqSxTqjQfOnBdRnCOoyJTvMp2TaJ5yo1xC_AGTLCz8Gquvy97cfTgTz5FK_$
> >  
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> > Users@einsteintoolkit.org
> > https://urldefense.com/v3/__http://lists.einsteintoolkit.org/mailman/listinfo/users__;!!DZ3fjg!8pjNitnVpXn7nbD_Tme73cqSxTqjQfOnBdRnCOoyJTvMp2TaJ5yo1xC_AGTLCz8Gquvy97cfTujfEcn8$
> >  
> >  


Yours,
Roland

-- 
My email is as private as my paper mail. I therefore support encrypting
and signing email messages. Get my PGP key from http://pgp.mit.edu .


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Re: [Users] Large junk radiation

[Zach Etienne]

Hi Deborah,

I'd be curious to see a comparison between the junk radiation you're seeing
now versus before, for the same physical scenario, grids, etc. Also, the
extra wiggles/reflections are typically caused not by junk radiation but by
a sharp gauge feature (https://arxiv.org/abs/1404.6523). The two can be
easily distinguished as the former propagates at c, and the latter at
sqrt(2) c (see paper for details).

-Zach

* * *
Zachariah Etienne
Assoc. Prof. of Physics, U. of Idaho
Adjunct Assoc. Prof. of Physics & Astronomy, West Virginia U.
https://etienneresearch.com
https://blackholesathome.net


On Tue, Aug 9, 2022 at 4:41 PM Erik Schnetter  wrote:

> Deborah
>
> One one hand, TwoPunctures has parameters to choose the resolution of
> the spectral grid it uses. I assume you are aware of these, and that
> you also know how to choose the 3D AMR grid setup parameters.
>
> TwoPunctures only solves for the conformal factor. It does per se not
> directly choose a lapse and a shift, but their choice is important in
> practice. Choosing \alpha=1 and \beta^i=0 as initial conditions is
> often not good. Similarly, choosing the antisymmetry lapse (with
> \alpha=-1 at the puncture) is also a bad idea (it is ill-posed). The
> TwoPunctures toolkit in the Einstein Toolkit has several options for
> choosing the initial gauge conditions. Personally, I am partial to
> initial_lapse = "twopunctures-averaged", but I am sure that others
> have other preferences.
>
> Of course, the BSSN gauge parameters used during evolution will also
> play a role.
>
> You can look at the gallery example at
>  for ideas.
>
> -erik
>
>
>
> On Tue, Aug 9, 2022 at 4:47 PM Ferguson, Deborah
>  wrote:
> >
> > Hi,
> >
> >
> >
> > We had been using our own version of TwoPunctures, and I’ve recently
> switched to the ETK version since it doesn’t require solving for the masses
> separately. Junk radiation has always been present, but I’m finding that
> some of my recent simulations have particularly loud junk radiation, which
> also makes it harder avoid reflection of. So I’m guessing I’m not fully
> understanding the TwoPunctures parameters.
> >
> >
> >
> > I’ve attached a parfile and a psi4 plot for a simulation I’ve started
> that’s having this large junk radiation, and was hoping someone could point
> out any mistakes I may have in the TwoPunctures parameters.
> >
> >
> >
> > Thanks!
> >
> > Deborah
> >
> >
> >
> > --
> >
> > Deborah Ferguson
> >
> > Post Doc
> >
> > University of Texas at Austin
> >
> > ___
> > Users mailing list
> > Users@einsteintoolkit.org
> > http://lists.einsteintoolkit.org/mailman/listinfo/users
>
>
>
> --
> Erik Schnetter 
> http://www.perimeterinstitute.ca/personal/eschnetter/
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