Unexpected Hamiltonian violation from Carpet boundaries, using CCZ4

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Issue #2540 new
KennethZen created an issue

While using CCZ4 to simulate a single star, the Hamiltonian constraint violation initially came from the star surface as expected, but after some time, the violation was dominated by areas near corners of refinement levels (by Carpet) as shown in following figures, which were strange. Any suggestions?

Thanks and regards,

KZ

Comments (1)

  1. Roland Haas

    Peter Diener addressed some of this in the mailing list: http://lists.einsteintoolkit.org/pipermail/users/2021-July/008064.html

    It is expected that the mesh refinement boundaries will reflect Hamiltonian constraint violations. From what you have provided us, it is not clear whether the level of constraint violations that you see is a cause of concern. You specifically mention CCZ4, but have you tried with BSSN? Does the constraint violations look better, the same, or worse with BSSN?

    It is also possible that an issue like this might be caused by some other problem potentially related to parameter settings, so in order to investigate this can you provide your thornlist and parameter file?

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