User: diener Date: 2011/04/27 01:44 PM
Modified: / ET.tex
Log: Some stuff in relativity tools.
File Changes:
Directory: / ============
File [modified]: ET.tex Delta lines: +25 -5 =================================================================== --- ET.tex 2011-04-27 18:39:57 UTC (rev 68) +++ ET.tex 2011-04-27 18:44:41 UTC (rev 69) @@ -1543,11 +1543,31 @@
\subsection{Relativity Tools\pages{3 Peter}}
-\paragraph{Black Hole Excision} +\subsubsection*{Vacuum-Matter Coupling} +The thorn \codename{TmunuBase} provides grid functions for the stress-energy +tensor $T_{\mu\nu}$ as well as schedule groups to manage when $T_{\mu\nu}$ is +calculated. In a simulation many different thorns may contribute to the +stress-energy tensor and this thorn allows them to do so without explicit +dependence on each other. The resulting stress-energy tensor can then be used +by the spacetime evolution thorn (again without explicit dependence on any +matter thorns). When thorn \codename{MoL} is used for time evolution this +provides a high order spacetime-matter coupling.
-\paragraph{Vacuum-Matter Coupling} +The grid functions provided by \codename{TmunuBase} are: +\begin{itemize} + \item The time compenent $T_{00}$ {\tt eTtt} + \item The mixed components $T_{0i}$ {\tt eTtx}, {\tt eTty}, {\tt eTtz} + \item The spatial components $T_{ij}$ {\tt eTxx}, {\tt eTxy}, {\tt eTxz}, {\tt eTyy}, {\tt eTyz}, {\tt eTzz} +\end{itemize} +In addition the grid scalar {\tt stress_energy_state} has the value 1 if storage is on for the stress-energy tensor and 0 if not.
-\paragraph{Object tracking} + +Thorn \codename{ADMCoupling} provides a similar (but older) interface between +space-time and matter thorns. However, since it is based on an include file +mechansim it is more complicated to use and we recommend all new matter thorns +to use \codename{TmunuBase} instead. + +\subsubsection*{Object tracking} \label{sec:object-tracking} We provide a module (\codename{PunctureTracker}) for tracking black hole positions when evolved with the moving puncture technique. This can be used @@ -1565,8 +1585,8 @@ puncture location usually does not coincide with gridpoints, the shift is interpolated to the location of the puncture. Equation~(\ref{eq:puncturetracking}) is implemented with a simple first order -Euler scheme, which seems to be accurate enough for controlling the mesh -refinement grids. +Euler scheme, which seems to be accurate enough for controlling the location +of the mesh refinement hierarchy. \todo{ES: I think this paragraph provides too much detail for this paper.} \todo{ES: Can also track objects via their maximum density or centre of mass; I believe GRHydro does something like this}