more wording clarifications for min_horizon_radius_points_for_mask

option


git-svn-id: http://svn.einsteintoolkit.org/cactus/EinsteinAnalysis/AHFinderDirect/trunk@1214 f88db872-0e4f-0410-b76b-b9085cfa78c5

1 files changed, 24 insertions, 12 deletions

diff --git a/doc/documentation.tex b/doc/documentation.tex
index fcb1e60..eb5d1aa 100644
--- a/doc/documentation.tex
+++ b/doc/documentation.tex
@@ -928,16 +928,18 @@ where
 \begin{array}{lcl}
 r_\text{inner}
 	& = &	\verb|mask_radius_multiplier| \times r_\text{horizon}
-		\,\,+\,\, \verb|mask_radius_offset| \times \Delta x
+		\,\,+\,\,
+		\verb|mask_radius_offset| \times {\Delta x}_\text{base}
 									\\
 r_\text{outer}
 	& = &	r_\text{inner}
-		\,\,+\,\, \verb|mask_buffer_thickness| \times \Delta x
+		\,\,+\,\,
+		\verb|mask_buffer_thickness| \times {\Delta x}_\text{base}
 									%%%\\
 \end{array}
 				\label{AHFinderDirect/eqn-r-inside-outside}
 \end{equation}
-and where $\Delta x$ is the base-grid Cactus grid spacing
+and where ${\Delta x}_\text{base}$ is the base-grid Cactus grid spacing
 (more precisely, the geometric mean of the base grid's $x$, $y$,
 and $z$ Cactus grid spacings)%%%
 \footnote{%%%
@@ -1030,12 +1032,11 @@ and $z$ Cactus grid spacings)%%%
 	(\eg{} \thorn{LegoExcision}) to crash. :(
 
 	This parameter can be used to avoid this problem:
-	\thorn{AHFinderDirect} only sets the mask for an
-	apparent horizon if
+	For each apparent horizon that it finds, \thorn{AHFinderDirect}
+	only sets the mask on a given grid if
 	\begin{equation}
-	r_{\min}
-	\ge
-	\verb|min_horizon_radius_points_for_mask| * {\Delta x}_{\max}
+	r_{\min} \ge \verb|min_horizon_radius_points_for_mask|
+		     * {\Delta x}_{\text{current},\max}
 	\end{equation}
 	where $r_{\min}$ is the minimum coordinate radius of
 	the apparent horizon (about the local coordinate origin),%%%
@@ -1043,13 +1044,24 @@ and $z$ Cactus grid spacings)%%%
 	 This may change soon to $r_\text{inner}$
 	 or $r_\text{outer}$.
 	 }%%%
-{}	and ${\Delta x}_{\max}$ is the maximum of the Cactus $x$, $y$,
-	and~$z$ grid spacings on the current Cactus grid.  If this condition
+{}	and ${\Delta x}_{\text{current},\max}$ is the maximum of the
+	Cactus $x$, $y$, and~$z$ grid spacings on the current Cactus
+	grid.%%%
+\footnote{%%%
+	 Note that this is the {\bf current\/} Cactus
+	 grid spacing, not the {\bf base\/} Cactus grid
+	 spacing that's used when calculating
+	 $r_\text{outer}$ and $r_\text{inner}$ by
+	 equation~\eqref{AHFinderDirect/eqn-r-inside-outside}.
+	 }%%%
+{}  If this condition
 	isn't satisfied, then \thorn{AHFinderDirect} skips setting the
 	mask for this apparent horizon, just as if this apparent
 	horizon wasn't found.  (Note that the various output files
-	are still written as usual; it's only the mask processing
-	for this horizon that's skipped.)
+	are still written, and the apparent horizon shape is still
+	used as the initial guess for the next time step's apparent-horizon
+	finding, all as usual; it's only the mask processing for
+	this horizon that's skipped (for this time step).)
 \end{description}
 
 \thorn{AHFinderDirect} supports two types of mask grid functions;