User: eschnett Date: 2012/03/12 09:43 AM
Modified: / ET.tex
Log: Describe how CarpetRegrid2 handles symmetries
File Changes:
Directory: / ============
File [modified]: ET.tex Delta lines: +7 -4 =================================================================== --- ET.tex 2012-03-12 14:37:57 UTC (rev 277) +++ ET.tex 2012-03-12 14:43:48 UTC (rev 278) @@ -2331,7 +2331,7 @@ Einstein Toolkit does not currently provide a suitable regridding thorn to create such a grid. If initial -conditions are constructed outside of {\tt Carpet} (which is often the +conditions are constructed outside of \codename{Carpet} (which is often the case), then the initial mesh hierarchy has to be defined manually. In order to facilitate the description of the mesh hierarchy the Einstein toolkit provides two regridding modules in @@ -2354,6 +2354,12 @@ \label{fig:bbh-boxes} \end{figure}
+If one wants to exploit a particular non-local symmetry of the domain +(e.g.\ a rotational symmetry, or periodicity in some directions), then +the grid structure also needs to have this symmetry. +\codename{CarpetRegrid2} thus contains code to enforce such symmetries +on the grid structures it creates (see Figure~\ref{fig:rot180-grid}). + \codename{CarpetRegrid} provides a number of different ways to specify the refined regions, e.g., as a set of boxes centered around the origin or as an explicit list of regions that make up the grid hierarchy. @@ -2369,9 +2375,6 @@ \codename{PunctureTracker} and \codename{NSTracker} (see section~\ref{sec:object-tracking}) in order to have the refined region follow the moving objects. -\codename{CarpetRegrid2} contains code to handle the $\pi$-symmetry -provided by \codename{RotatingSymmetry180}, enforcing the symmetry on -the resulting grid layout (see Figure~\ref{fig:rot180-grid}). \begin{figure}[htbp] \begin{center} \includegraphics[width=0.3\textwidth]{rot180-grid}