<div dir="ltr">Thank you Roland,<div><br></div><div><a href="https://arxiv.org/abs/1704.07383">https://arxiv.org/abs/1704.07383</a> is exactly what I want to repeat.</div><div><br></div><div>Thank you for you help, I will contact the 1st author for help of your paper if I failed.</div><div><br></div><div>Best Wishes.<br></div><div><br></div><div>Yours,</div><div>Zhi-Chao.</div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">2017-08-18 23:44 GMT+08:00 Roland Haas <span dir="ltr"><<a href="mailto:roland.haas@physics.gatech.edu" target="_blank">roland.haas@physics.gatech.edu</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hello all,<br>
<span class=""><br>
> Could you give more details about the physics you are trying to add?<br>
> "atmosphere" in this context usually means an artificial low density<br>
> fluid in a matter simulation which helps with numerical problems that<br>
> occur when the density drops to zero. It doesn't make sense to add<br>
> it to a BBH simulation, which is vacuum.<br>
><br>
> Do you mean that you want to add a low density fluid to a BBH<br>
> simulation?<br>
</span>In case you are planning something similar to<br>
<a href="https://arxiv.org/abs/1704.07383" rel="noreferrer" target="_blank">https://arxiv.org/abs/1704.<wbr>07383</a> then you may want to contact the first author (Joseph Fedrow) possibly through this list (he's subscribed). Typically you will get failures of con2prim near the punctures and have to take special measures to work around it.<br>
<br>
Usually this involves setting<br>
<br>
* GRHydro::recon_method = ppm # since it is very robust<br>
* GRHydro::reconstruct_Wv = yes # avoids some v^2>c^2 situations<br>
* GRHydro::riemann_solver = "Marquina" # better than HLLE for this<br>
* GRHydro::sqrtdet_thr = 10. # or so, these apply Joshua Faber's<br>
methods described in <a href="https://arxiv.org/abs/0708.2436" rel="noreferrer" target="_blank">https://arxiv.org/abs/0708.<wbr>2436</a><br>
* GRhydro::c2p_resort_to_<wbr>bisection = yes # try bisection if<br>
Newton-Raphson iteration fails<br>
<br>
Note that my recollection of the paper by Fedrow (I am a co-author) was<br>
that all of those were required but not quite enough and that Christian<br>
Ott had to write a special con2prim routine that handled the BH interior<br>
carefully.<br>
<br>
There is a also code in TwoPunctures that can solve the constraints<br>
(the TP code is in the ET but not the code that eg provides a density<br>
profile). Again best would be to contact the authors (all reachable<br>
through this list).<br>
<br>
Yours,<br>
Roland<br>
<span class="HOEnZb"><font color="#888888"><br>
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</font></span></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div>赵志超</div><div>中国科学院高能物理研究所</div><div>中国 北京</div><div>18401696963</div><div><a href="mailto:yanyuechuixue@gmail.com" target="_blank">yanyuechuixue@gmail.com</a></div></div></div>
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