Hi everyone,
I am a PhD student at the IFT in Madrid. I am trying to adapt the par/arxiv-1111.3344 /bbh.par parameter file to a hyperbolic encounter with an initial separation of 100M. In fact, my problem is very similar to the one here: http://lists.einsteintoolkit.org/pipermail/users/2020-February/007292.html
Learning from the GW150914.rpar parameter file, I have turned the bbh.par into a .rpar file, so that I can automatically set some parameters such as the initial positions, momenta, masses, etc. In addition, I have set the boundaries to 768 to accommodate the new initial positions x = ±50 and increased the refinement levels from 7 to 10, increasing a bit the resolution of the finest grid (from 2/2^6=0.03125 to 12.8/2^9=0.025). I have also disabled all the HDF5 output as well as the 180º rotating symmetry, since I will later want to use it for different masses, and enabled the QuasiLocalMeasures thorn. Finally, by following the advice for the mentioned doubt of February 2020, I have increased the parameters TwoPunctures::npoints_A,B,phi to 50, 50 and 20, respectively.
I thought that I had it, since the simulation was successfully running, even past the point of closest approach. However, shortly after that, the parameter "ML_BSSN::trK norm2" that the output showed abruptly turned to -nan and the simulation crashed. Could anyone help me find the problem? I thought it might be the resolution, but the bbh.par has a bit worse finest grid resolution and it runs smoothly, even with stronger fields involved. Could the problem be in the initial conditions generated by TwoPunctures at such large distances?
I attach the .rpar file in case it helps. I am very new to the Einstein Toolkit, so I might very well have overlooked something relevant.
Thank you in advance.
Best regards, Santiago