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git-svn-id: http://svn.einsteintoolkit.org/cactus/EinsteinAnalysis/AHFinderDirect/trunk@754 f88db872-0e4f-0410-b76b-b9085cfa78c5

1 files changed, 21 insertions, 14 deletions

diff --git a/param.ccl b/param.ccl
index 0e040d5..bc2e1e6 100644
--- a/param.ccl
+++ b/param.ccl
@@ -297,8 +297,10 @@ real origin_z[5] "global z coordinate of patch system origin"
 
 keyword patch_system_type "what type of patch system should we use?"
 {
+# choose this for normal use
 "match Cactus grid symmetry" :: \
   "choose automagically based on grid symmetries and the patch system's origin"
+
 "full sphere"	:: "full sphere, no symmetries"
 "+z hemisphere"	:: "mirror symmetry across z=0 plane"
 "+xy quadrant"	:: "90 degree periodic rotation symmetry about z axis"
@@ -308,6 +310,9 @@ keyword patch_system_type "what type of patch system should we use?"
 		    90 degree periodic rotation symmetry about z axis"
 } "match Cactus grid symmetry"
 
+# this must be at least
+# * 2 if FINITE_DIFF_ORDER is set to 4 in "src/include/config.hh"
+# * 1 if FINITE_DIFF_ORDER is set to 2 in "src/include/config.hh"
 int N_ghost_points "number of ghost zones on each side of a patch"
 {
 0:* :: "any integer >= 0"
@@ -327,10 +332,18 @@ int N_overlap_points \
 # for better performance, without seriously affecting the accuracy
 # with which we can locate the horizon.
 #
+# This spacing must integrally divide 90 degrees for full sphere patch
+# systems, or 45 degrees for other patch systems.
+#
+# Also, the computation of surface integrals over the horizon (for horizon
+# areas, masses, and centroids) is most accurate if the number of angular
+# grid zones (i.e. the patch size divided by this parameter) is even or
+# >= 7 (or both) for both coordinates of all patches.
+#
 real delta_drho_dsigma "angular grid spacing of patches, in degrees"
 {
 (0.0:* :: "any real number > 0.0"
-} 9.0
+} 7.5
 
 ################################################################################
 
@@ -338,17 +351,6 @@ real delta_drho_dsigma "angular grid spacing of patches, in degrees"
 # parameters for how we compute surface integrals over the horizon
 #
 
-##keyword surface_integral_method \
-##  "how do we compute surface integrals over the horizon?"
-##{
-##"trapezoid", "trapezoid rule"	:: \
-##  "trapezoid rule (2nd order for smooth functions)"
-##"Simpson", "Simpson's rule"	:: \
-##  "Simpson's rule (4th order for smooth fns, requires N to be even)"
-##"Simpson (variant)", "Simpson's rule (variant)"	:: \
-##  "Simpson's rule variant (4th order for smooth fns, requires N >= 7)"
-##} "Simpson"
-
 # ... N is the number of grid zones in a patch, in either direction
 keyword surface_integral_method \
   "how do we compute surface integrals over the horizon?"
@@ -361,6 +363,9 @@ keyword surface_integral_method \
 "Simpson (variant)"	:: "alternate name for Simpson's rule variant"
 "Simpson's rule (variant)":: \
   "Simpson's rule variant (4th order for smooth fns, requires N >= 7)"
+
+# choose this for normal use (assuming FINITE_DIFF_ORDER is set to 4
+# in "src/include/config.hh")
 "automatic choice"	:: \
   "choose Simpson's rule or variant if applicable, otherwise trapezoid rule"
 } "automatic choice"
@@ -481,6 +486,7 @@ real geometry__Schwarzschild_EF__Delta_xyz \
 # accuracy right up to the edge of the data range.  In practice a Lagrange
 # polynomial interpolant works well.
 #
+
 string interpatch_interpolator_name \
   "name under which the interpatch interpolation operator is registered in Cactus"
 {
@@ -504,9 +510,10 @@ keyword initial_guess_method \
   "method used to set up initial guess for apparent horizon shape"
 {
 "read from file"   :: "read from input file"
-"Kerr/Kerr"	   :: "set to the horizon of Kerr spacetime in Kerr coordinates"
+"Kerr/Kerr"	   :: \
+  "set to the (analytical) horizon of Kerr spacetime in Kerr coordinates"
 "Kerr/Kerr-Schild" :: \
-  "set to the horizon of Kerr spacetime in Kerr-Schild coordinates"
+  "set to the (analytical) horizon of Kerr spacetime in Kerr-Schild coordinates"
 "ellipsoid"	   :: "set to a coordinate ellipsoid"
 "sphere"           :: "set to a coordinate sphere"
 } "read from file"