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]> 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]> 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] > > 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] > > http://lists.einsteintoolkit.org/mailman/listinfo/users > > > > -- > Erik Schnetter <[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] 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 ----------------------------------------------------------------------
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