1 | Difficulties for H(HPF), H2(HPF-2) and D(DAGH) are given from 1-3, where 1=easy, 2=medium and 3 =difficult implement. |
2 | Difficulties inherent to the BBH Problem H H2 D Comments |
3 | Linear wave problem. No "inner boundaries" 1 1 1 lapse=1, shift=0, no holes. |
4 | Linear wave problem with matching outer |
5 | Boundary condition for grav. wave extraction. 2 1 3 The outer boundary requires a 1d evolution. |
6 | Adaptive Mesh Refinements (AMR) 3 2 1 DAGH was designed for this purpose. |
7 | Multigrid/MLAT + AMR 3 2 1-3 Only a certain class of problems can |
8 | be solved with DAGH. |
9 | Spherical "inner boundary" in Cartesian coords 2 2 2 DAGH: large stencils on the inner |
10 | boundary-expensive communications. |
11 | HPF: 3D "sparse" array or extrinsic. |
12 | Moving "inner boundary". 3 1 1 Irregular boundary makes it difficult to implement in HPF. |
13 | Finding the Apparent Horizon 1 1 1 Expand Spherical Harmonics. |
14 | Causal Differencing with a "real" shift. 2 2 1 Requires additional storage in HPF. |
15 | NOTE:The mass curves spacetime, the shift tells us where to |
16 | interpolate to. |