Description
Apparent horizons (AH) are crucial diagnostics in numerical relativity (NR), which allows us to identify the existence of black holes (BH). While many AH finders based on different techniques exist, an efficient and flexible finder that can handle the most general spacetime symmetry assumptions remains challenging, particularly for integration into existing evolution codes like Gmunu. We present a Python-based AH solver that utilizes PETSc, capable of handling spherically symmetric and axisymmetric configurations, by implementing finite-difference approximations for the expansion scalar. The ultimate goal is to construct a robust multigrid-based solver that can be integrated into the Gmunu code, providing a versatile tool for AH tracking in NR simulations.
