Hello Yuhua,

sorry for the very late response.

Looking at just the error that you pasted in I cannot really say what may be going wrong.

This does not directly have anything to do with mesh refinement since the error is from the Hydro code that cannot solve a particular non-linear equation for a particular point in the simulation.

This can happen if your simulation does not have enough resolution to resolve the required features.

Where did you take the Hydro_RNSID parfile from? If it is one from a "test" directory then it is only a regression test and not intended to be used for actual evolutions.

As a rule of thumb you need at least 80 points across the diameter of the star to avoid issues. You could try the tov example in the gallery: https://www.einsteintoolkit.org/gallery/ns/ and replace the parts in the parfile given there that refer to "TOV" and "TOVSolver" by RNSID.

Yours, Roland

Hello all,

When I doing the simulation Hydro_RNSID in Einstein Toolkit. I met some problems:

WARNING[L1,P0] (GRHydro): Con2Prim failed; stopping the code. WARNING[L1,P0] (GRHydro): Even with mesh refinement, this point is not restricted from a finer level, so this is really an error WARNING[L1,P0] (GRHydro): on carpet reflevel: 1 WARNING[L1,P0] (GRHydro): xyz location: 0.000000 -6.000000 0.000000 WARNING[L1,P0] (GRHydro): radius: 6.000000 WARNING[L1,P0] (GRHydro): hydro_excision_mask, C2Pfailed: 0 1.000000 WARNING[L1,P0] (GRHydro): rho eps press w_lorentz: 0.1057347E-05 0.1857035 0.1963532E-06 1.047789 WARNING[L1,P0] (GRHydro): velocities: 0.2045605 -0.4772050E-01 0.9116232E-16 WARNING[L1,P0] (GRHydro): dens tau: 0.3259242E-05 0.8464639E-06 WARNING[L1,P0] (GRHydro): scon: 0.1949336E-05 -0.3921220E-06 0.8515884E-21 WARNING[L1,P0] (GRHydro): 3-metric: 2.054383 0.8422013E-01 0.3666352E-20 2.115545 -0.1509363E-20 1.994599 WARNING[L1,P0] (GRHydro): lapse, shift: 0.6504332 -0.9400928E-01 -0.2831831E-01 -0.3942654E-21 WARNING level 0 from host lyh-Lenovo process 0 while executing schedule bin CCTK_POSTSTEP, routine GRHydro::check_GRHydro_C2P_failed in thorn GRHydro, file GRHydro_Con2Prim.F90:1847: -> Aborting.

I don't know how to mesh refinement.

Yours, Yuhua