<div dir="ltr">Hello,<div><br></div><div>two years ago I performed a convergence test of GRHydro. </div><div>I found that the PPM scheme converges, but not the WENO one.</div><div>Difficult to say what version of ET I used, but I'd guess the last one</div><div>of 2018.</div><div><br></div><div>I dug up the two attached plots. This was with a piecewise polytrope,</div><div>but the result is the same with a single polytrope. You can clearly</div><div>see how increasing the resolution does not decrease the amplitude</div><div>of the oscillation of rho in the case of WENO, but it does so in the case</div><div>of PPM. The initial data is a TOV star and no magnetic fields were used. </div><div>I don't have the par files anymore. </div><div><br></div><div>I didn't investigate much further because I use IllinoisGRMHD and it </div><div>is possible that I was doing something wrong. However, this conversation is</div><div>giving support to the idea that WENO might have problems.</div><div><br></div><div>Gabriele</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Jun 10, 2021 at 2:52 PM Hee Il Kim <<a href="mailto:heeilkim@gmail.com">heeilkim@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>Thanks Roland and Maria</div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">2021년 6월 10일 (목) 오후 11:50, Roland Haas <<a href="mailto:rhaas@illinois.edu" target="_blank">rhaas@illinois.edu</a>>님이 작성:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hello Hee Il,<br>
<br>
from your email it seems that you are seeing differences between<br>
different ET releases but with the same par file.<br></blockquote><div><br></div><div>I'm not seeing different results between Turing and Lorentz. Since they are identical, I've shown only representative plots (rhomax vs time btw). The issue is that he WENO of the ET versions do not produce the same inspiraling time with that of WENO-Z, MP5, and PPM, whereas the other three recon methods show decent coincidence for the inspiralling time.</div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<br>
Yet your plot seems to not show any pair of curves that only differ by<br>
the release code used.<br></blockquote><div><br></div><div>Explained above.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<br>
If you are comparing to the runs by the Parma group (or any<br>
simulation) then you must ensure that you are comparing "apples with<br>
apples" ie you would have to run their parfiles with the current ET<br>
release (to check for a change) and also with their code (to check if<br>
the issue is compiler / cluster changes).<br>
<br></blockquote><div><br></div><div>I'm not going to compare my current results to the Parma group runs. As you discussed in the meeting, since they used the recon codes and Con2Prim for the MHD, it might give different results. But if the differences are big even with zero B, I think it needs to be examined further in the future.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
They provide their code and parfiles in:<br>
<br>
<a href="https://einstein.pr.infn.it/svn/numrel/pub/" rel="noreferrer" target="_blank">https://einstein.pr.infn.it/svn/numrel/pub/</a><br>
<br>
See "Background material" on <br>
<br>
<a href="https://einstein.pr.infn.it/gravity/Research/BNS2016.html" rel="noreferrer" target="_blank">https://einstein.pr.infn.it/gravity/Research/BNS2016.html</a><br>
<br>
which is listed on the "Additional Resources" page of:<br>
<br>
<a href="https://docs.einsteintoolkit.org/et-docs/Additional_resources" rel="noreferrer" target="_blank">https://docs.einsteintoolkit.org/et-docs/Additional_resources</a><br>
<br>
Yours,<br>
Roland<br></blockquote><div><br></div><div>I've been aware of it and used its grid setup. At first, I didn't follow their parfile but used my own grid amr with NSTracker. But for the comparison, I followed the parfiles there. I haven't tried to use the entire code of the Parma group. But at least I found their Lorene is different from official Lorene and ET Lorenes. I've made an ID by using their Lorene but the ID was not readable by recent ET/GRHydros.</div><div><br></div><div>My feeling is that GRHydro_WenoRecontruct codes need to be examined.</div><div><br></div><div>Thanks,</div><div><br></div><div>Hee Il</div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<br>
> Hi<br>
> <br>
> I'm reporting on recon_method dependency issue at least found in Turing and<br>
> Lorentz. I've been studying BNS evolution by taking some of the Parma group<br>
> models as references (DOI: 10.1103/PhysRevD.93.064047). But there were<br>
> significant differences in merger time, t_merger. At the moment, I will put<br>
> aside direct comparison between the GRHydro of Parma and recents ones.<br>
> <br>
> What I've found is that WENO of Turing/Lorentz produces much shorter<br>
> inspiraling time (See the attached figure). But WENO-Z/PPM/MP5, they all<br>
> produce similar inspiraling time. Of course, depending on resolutions, they<br>
> produce different merging behaviour but as shown in the figure, higher-res<br>
> PPM matches with lower-res WENO-Z nicely, which is consistent with our<br>
> expectations. I've got the identical results for both Turing and Lorentz<br>
> versions.<br>
> <br>
> I've missed recent GRHydro developments for a long time and I have no<br>
> guesses for the discrepancy. I hope GRHydro developers examine this issue<br>
> for the consistency of the recon_method. Thanks for your help in advance.<br>
> <br>
> Hee Il<br>
<br>
<br>
-- <br>
My email is as private as my paper mail. I therefore support encrypting<br>
and signing email messages. Get my PGP key from <a href="http://pgp.mit.edu" rel="noreferrer" target="_blank">http://pgp.mit.edu</a> .<br>
</blockquote></div></div>
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