Added comments.

git-svn-id: http://svn.einsteintoolkit.org/cactus/EinsteinEvolve/LegoExcision/trunk@16 f75ba9e5-694f-0410-ac2c-87ea7ce7132b

1 files changed, 18 insertions, 3 deletions

diff --git a/src/findboundary.F90 b/src/findboundary.F90
index c729fe8..0dbc5b6 100644
--- a/src/findboundary.F90
+++ b/src/findboundary.F90
@@ -26,25 +26,40 @@ subroutine excision_findboundary (ierr, mask, ni, nj, nk)
   
   ! inout: mask
   CCTK_REAL    :: mask(ni,nj,nk)
-  
+
+! Internal variables.
+
   integer i,j,k
   integer ii,jj,kk
   logical bnd
-  
+
+! Loop over grid points.
+
   do k=2,nk-1
      do j=2,nj-1
         do i=2,ni-1
+
+!          Check if we are in an excised point.
+
            if (mask(i,j,k)==MASK_EXCISED) then
+
               bnd = .false.
+
+!             If any neighbour is active, mask the point
+!             as a boundary point.
+
               do kk=k-1,k+1
                  do jj=j-1,j+1
                     do ii=i-1,i+1
-                       bnd = bnd .or. mask(ii,jj,kk)==MASK_ACTIVE
+                       bnd = bnd.or.mask(ii,jj,kk)==MASK_ACTIVE
                     end do
                  end do
               end do
+
               if (bnd) mask(i,j,k) = MASK_BOUNDARY
+
            end if
+
         end do
      end do
   end do