From 57665a99a9a599290fce034cbf9309148ec52152 Mon Sep 17 00:00:00 2001
From: jthorn <jthorn@f88db872-0e4f-0410-b76b-b9085cfa78c5>
Date: Fri, 16 Jan 2004 14:45:35 +0000
Subject: better document which of the radia, circumferences, and areas in the
 BH_diagnostics file are coordinate vs proper quantities

git-svn-id: http://svn.einsteintoolkit.org/cactus/EinsteinAnalysis/AHFinderDirect/trunk@1242 f88db872-0e4f-0410-b76b-b9085cfa78c5
---
 doc/documentation.tex | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

(limited to 'doc')

diff --git a/doc/documentation.tex b/doc/documentation.tex
index 4695ce8..360234c 100644
--- a/doc/documentation.tex
+++ b/doc/documentation.tex
@@ -829,23 +829,24 @@ controlled by the following parameters:
 		\item	the Cactus time coordinate \verb|cctk_time|
 		\item	the Cactus $(x,y,z)$ coordinates of the apparent
 			horizon centroid
-		\item	the minimum, maximum, and mean radia
+		\item	the minimum, maximum, and mean coordinate radia
 			of the apparent horizon about the local
 			coordinate origin
 		\item	the minimum and maximum Cactus $x$, $y$, and $z$
 			coordinates of the apparent horizon surface
-		\item	the $xy$, $xz$, and $yz$-plane circumferences
-			of the apparent horizon%%%
+		\item	the proper circumferences of the apparent horizon
+			in the $xy$, $xz$, and $yz$ local-coordinate planes%%%
 \footnote{%%%
-	 Alas, these are computed using the
-	 $xy$, $xz$, and $yz$-planes passing through
-	 the local coordinate origin, so they may be
-	 considerably different (smaller) than the
-	 actual circumferences if the apparent horizon
-	 is displaced significantly from the local
-	 coordinate origin.
+	 Note that if the apparent horizon is not
+	 symmetric across one of these coordinate planes,
+	 then the circumference in this plane is not
+	 very meaningful.  In particular, in this case
+	 this circumference is probably different from
+	 the apparent horizon's maximum ``hoop'' circumference.
 	 }%%%
-		\item	the area of the apparent horizon, $A$
+		\item	the $xz/xy$ and $yz/xy$ ratios of the proper
+			circumferences
+		\item	the proper area of the apparent horizon, $A$
 		\item	the irreducible mass of the apparent horizon,
 			$\sqrt{A/16\pi}$
 		\end{itemize}
-- 
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