<div dir="ltr">Vassili<div><br></div><div style>In my experience, one needs to "control" the puncture by ensuring that (a) things evolve only slowly there (keeping the lapse small) and (b) adding sufficient dissipation.</div>
<div><br></div><div style>What is the value of the lapse near the puncture?</div><div style>How much dissipation are you adding?</div><div style>To which variables are you adding dissipation?</div><div style><br></div><div style>
-erik</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Wed, Feb 27, 2013 at 8:53 AM, Vassilios Mewes <span dir="ltr"><<a href="mailto:vassilios.mewes@uv.es" target="_blank">vassilios.mewes@uv.es</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hello all,<div><br></div><div>still no success with the full evolution of BH+torus...</div><div><br></div>
<div>i have attached the par file i have been using lately, in which i added two more levels of mesh refinement, as Roland suggested, increased the Dissipation order to 5th and removed the parameter ML_BSSN::dt_lapse_shift_method = "noLapseShiftAdvection"..</div>
<div><br></div><div>this has improved things a bit, but the L_inf norm of the hamiltonian constraint still starts growing at around t=200 (after having decreased and then having been rather constant up to that point) and then the simulation will crash later (either due to the shift being nan at the puncture or by detecting nans)</div>
<div><br></div><div><br></div><div>in the meantime, i have evolved a single puncture, the bondi accretion onto a puncture and an "inverse cowling" (setting up the spacetime and hydro variables of the BH+torus system but only evolving the spacetime), all using the same parameters, and all of those work...its only the full system of BH+torus when i run into problems...this is using the ET 2012.11. release..</div>
<div><br></div><div>do you have any ideas what might go wrong with the spacetime evolution when evolving the full system?</div><div><br></div><div>best wishes,</div><div><br></div><div>
Vassili</div></div><div class="gmail_extra"><br><br><div class="gmail_quote"><div><div class="h5">On Tue, Feb 12, 2013 at 2:07 AM, Roland Haas <span dir="ltr"><<a href="mailto:roland.haas@physics.gatech.edu" target="_blank">roland.haas@physics.gatech.edu</a>></span> wrote:<br>
</div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5">Hello Vassilios,<br>
<div><br>
> as mentioned earlier in the ET phone call, i have attached the par file<br>
> used in the run...<br>
><br>
> i tried checking for the nans in the output, but the last hdf5 output was<br>
> too many iterations earlier and they aren't visible in 1D ascii output<br>
> either<br>
><br>
> as said, the puncture tracker actually aborted the run, not the nan<br>
> checker...<br>
</div>Thank you for the parameter file. As a unsubstantiated guess, I would<br>
try what happens if you move the outer boundary further out. Right now<br>
it sits at 50M which I would find uncomfortably close if there is any<br>
say "junk" radiation (eg from setting up a BH with spin in flat<br>
background) present. I'd move it to at least 200M (ie two more levels of<br>
mesh refinement). Not sure how likely this explanation is since your<br>
NaNs appear after many (9) light crossing times.<br>
<br>
Yours,<br>
Roland<br>
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br>Erik Schnetter <<a href="mailto:schnetter@cct.lsu.edu" target="_blank">schnetter@cct.lsu.edu</a>><br><a href="http://www.perimeterinstitute.ca/personal/eschnetter/" target="_blank">http://www.perimeterinstitute.ca/personal/eschnetter/</a>
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