Add some comments explaining the variables

git-svn-id: http://svn.cactuscode.org/arrangements/CactusNumerical/SphericalSurface/trunk@15 40f6ab95-0e4f-0410-8daa-ee8d7420be1d

1 files changed, 25 insertions, 13 deletions

diff --git a/interface.ccl b/interface.ccl
index 9f41197..363489f 100644
--- a/interface.ccl
+++ b/interface.ccl
@@ -7,36 +7,48 @@ IMPLEMENTS: SphericalSurface
 
 PUBLIC:
 
-# to be defined by the setting thorn
+# To be defined by the setting thorn.
+# Suggested meanings: 
+# zero:     No surface is provided at this time step
+# negative: No surface could be found at this time step
+# positive: The surface data are valid
 CCTK_INT sf_valid[nsurfaces] TYPE=scalar
 
 
 
 CCTK_REAL sf_info[nsurfaces] TYPE=scalar
 {
+  # The following are covariant quantities:
+  
+  # proper area:
+  #    A := int(S) sqrt(q) dS
+  #    with q_ij the 2-metric on the surface
+  sf_area
+  
+  
+  
   # The following are coordinate-dependent quantities:
   
-  # monopole moment; M := sqrt(A / 4pi)   (average coordinate radius)
-  #    with the coordinate area A := int(S) dS
+  # monopole moment (average coordinate radius):
+  #    M := int(S) h ds / A
   sf_mean_radius
-  sf_min_radius sf_max_radius
 
-  # dipole moment; D^i := int(S) x^i dS / A
+  # dipole moment:
+  #    D^i := int(S) x^i dS / A
   sf_centroid_x sf_centroid_y sf_centroid_z
 
-  # quadrupole moment; Q^ij := int(S) y^i y^j dS / A   with y^i := x^i - D^i
+  # quadrupole moment:
+  #    Q^ij := int(S) y^i y^j dS / A   with y^i := x^i - D^i
   sf_quadrupole_xx sf_quadrupole_xy sf_quadrupole_xz
   sf_quadrupole_yy sf_quadrupole_yz sf_quadrupole_zz
-
-  # bounding box
-  sf_min_x sf_min_y sf_min_z sf_max_x sf_max_y sf_max_z
-  
   
   
-  # The following are covariant quantities:
   
-  # area; A := int(S) sqrt(q) dS   with q_ij the 2-metric on the surface
-  sf_area
+  # minimum and maximum coordinate radius
+  sf_min_radius sf_max_radius
+
+  # bounding box
+  sf_min_x sf_min_y sf_min_z sf_max_x sf_max_y sf_max_z
 } "Surface information"