DAGH and HPF’s Role in the BBH GC
Adaptive Mesh Refinement is used to control the memory requirements needed by the physics. Without AMR we would need ~6871 Gigabytes of memory for accurate waveform extraction.
AMR determines where to place grid points, and uses a hierarchy of grids of different levels to achieve high accuracy with “low” memory costs.
The Grids dynamically adapt to the equations using a truncation error estimate with Finite Difference codes.
HPF can handle the majority of problems in the BBH problem, but it is very difficult to implement in HPF 1 or 2. The load balancing will never be ideal.
DAGH (Distributed Adaptive Grid Hierarchy) was designed for implementing AMR on parallel computers for finite difference codes.