Hello all,

still no success with the full evolution of BH+torus...

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"..

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)

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..

do you have any ideas what might go wrong with the spacetime evolution when evolving the full system?

best wishes,

Vassili

On Tue, Feb 12, 2013 at 2:07 AM, Roland Haas <roland.haas@physics.gatech.edu> wrote:

Hello Vassilios,

> as mentioned earlier in the ET phone call, i have attached the par file
> used in the run...
>
> i tried checking for the nans in the output, but the last hdf5 output was
> too many iterations earlier and they aren't visible in 1D ascii output
> either
>
> as said, the puncture tracker actually aborted the run, not the nan
> checker...

Thank you for the parameter file. As a unsubstantiated guess, I would
try what happens if you move the outer boundary further out. Right now
it sits at 50M which I would find uncomfortably close if there is any
say "junk" radiation (eg from setting up a BH with spin in flat
background) present. I'd move it to at least 200M (ie two more levels of
mesh refinement). Not sure how likely this explanation is since your
NaNs appear after many (9) light crossing times.

Yours,
Roland

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