The Thorns

Here we give a brief description of each of the thorns contained in this arrangement.

• ADM evolves $\gamma_{ij}$ and $K_{ij}$ via the standard ADM equations; this thorn is semi-obselete, as it doesn't use the modern method of lines generic evolution scheme (provided by the MoL thorn in the CactusBase arrangement); it's not clear if there's any Cactus thorn which evolves the ADM equations using the method of lines^part202

• ADMAnalysis routines run at CCTK_ANALYSIS to compute various quantities

• ADMConstraints computes the $3+1$ Hamiltonian (energy) and momentum constraints

• ADMCoupling allows thorns to `register' their matter field contributions to the stress energy tensor

• ADMMacros macros for computing various quantities which are commonly used in $3+1$ numerical relativity, such as Christoffel symbols, covariant derivatives, the Ricci tensor, etc etc; some of these support both 2nd and 4th order finite differencing

• AHFinder searches for apparent horizons^part203

• CoordGauge manages gauge quantities

• EvolSimple a demo evolution thorn

• Extract `extracts' gravitational-wave waveforms

• IDAnalyticBH analytic black hole initial data

• IDAxiBrillBH axisymmetric Brill wave with black hole initial data

• IDBrillData Brill wave initial data

• IDLinearWaves linearized wave initial data

• IDSimple a demo initial data thorn, provides Minkowski space with conformal factor

• Maximal maximal slicing gauge condition

• PsiKadelia computes various Neumann-Penrose quantities

• SpaceMask provides a `mask' for the spatial grid

• StaticConformal provides for a static conformal factor

• TimeGeodesic computes timelike geodesics