[Commits] [svn:einsteintoolkit] Paper_EinsteinToolkit_2010/ (Rev. 278)

[schnetter at cct.lsu.edu]

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}