Hi Bruno, I have gone through the notebook in the past and from what I could see, the version of paper I (10.1103/PhysRevD.85.064040) is implemented in the code, kappa_3 is encoded in the parameter 'ML_CCZ4::GammaShift', and the changes for the scaling of kappa_1 and kappa_2 with the lapse (eq. 27 and 28 in paper II, 2013) are not implemented.
I hope this helps. Best, Michael Müller ________________________________ From: [email protected] <[email protected]> on behalf of Bruno Giacomazzo <[email protected]> Sent: Thursday, June 2, 2022 10:04 AM To: Erik Schnetter <[email protected]> Cc: Einstein Toolkit Users <[email protected]>; Paolo Garimberti <[email protected]> Subject: Re: [Users] question about ML_CCZ4 parameters CAUTION: This email originated from outside of the University of Guelph. Do not click links or open attachments unless you recognize the sender and know the content is safe. If in doubt, forward suspicious emails to [email protected] Hi Erik, thanks a lot for the offer to help. I will try to have a look by myself first at the mathematica notebook. Unless anybody else knows on what paper CCZ4 in McLachlan is based on. :-) Cheers, Bruno Il giorno mer 1 giu 2022 alle ore 22:48 Erik Schnetter <[email protected]<mailto:[email protected]>> ha scritto: Bruno Although I was probably around when the CCZ4 formulation was implemented, I don't recall. I usually resolve to archaeology, comparing the equations in the respective Mathematica scripts to equations found in publications. If no one else speaks up, I can assist with this – we'd set up a Zoom meeting, and I can show how to read (or modify!) the Mathematica script that implements these equations. -erik On Tue, May 31, 2022 at 6:21 AM Bruno Giacomazzo <[email protected]<mailto:[email protected]>> wrote: > > Together with a student of mine we are trying to use the CCZ4 formulation > implemented in McLachlan. We saw that most parameters are the same as in > BSSN, but there are damping factors that need to be selected. > > In Alic et al 2013 (https://link.aps.org/doi/10.1103/PhysRevD.88.064049) they > mention 3 damping factors (k1, k2, and k3), but in the param.ccl of > McLachlan/ML_CCZ4 only k1 and k2 are mentioned (assuming they are the same). > > Is it because k3 is hardcoded to the value suggested in Alic et al 2013? Or > does McLachlan/ML_CCZ4 use a different set of evolution equations (in which > case, is there a reference)? > > We were able to find some example parameter files (for example the ones from > the Parma group https://einstein.pr.infn.it/gravity/Research/BNS2015.html) > and we found that they used indeed k1 and k2 from Alic et al 2013: > ML_CCZ4::dampk1 = 0.05 > ML_CCZ4::dampk2 = 0 > > We also saw that they added ML_CCZ4::ML_Theta to the Dissipation vars and set > ML_CCZ4::apply_dissipation = "never". > The other parameters look the same as when using BSSN. > > Since I never used ML_CCZ4 I want to be sure that I'm setting the parameters > correctly and the damping factors seem to be the most delicate point. > > Thanks, > Bruno > > -- > > Prof. Bruno Giacomazzo > Department of Physics > University of Milano-Bicocca > Piazza della Scienza 3 > 20126 Milano > Italy > > email: [email protected]<mailto:[email protected]> > phone: (+39) 02 6448 2321 > web: http://www.brunogiacomazzo.org > > ---------------------------------------------------------------------- > There are only 10 types of people in the world: > Those who understand binary, and those who don't > ---------------------------------------------------------------------- > > _______________________________________________ > Users mailing list > [email protected]<mailto:[email protected]> > http://lists.einsteintoolkit.org/mailman/listinfo/users -- Erik Schnetter <[email protected]<mailto:[email protected]>> http://www.perimeterinstitute.ca/personal/eschnetter/ -- Prof. Bruno Giacomazzo Department of Physics University of Milano-Bicocca Piazza della Scienza 3 20126 Milano Italy email: [email protected]<mailto:[email protected]> phone: (+39) 02 6448 2321 web: http://www.brunogiacomazzo.org<http://www.brunogiacomazzo.org/> ---------------------------------------------------------------------- There are only 10 types of people in the world: Those who understand binary, and those who don't ----------------------------------------------------------------------
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