anchor.diff:        parameter(rr2 = 4)
         integer i2(0:rr2-1),j2(0:rr2-1)
   
  +      integer a(2,2), ainv(2,2), d, f(2), iff, jff
  +
         logical is_valid_average, skip_this_grid
   
   
  
positive.code:      &         '  Refratio**2 is not equal to rr2'
           stop
        endif
  
  
  c    # Visit each fine grid face and fill in correction term into
  c    # qfine_dummy. We don't really know which face corresponds
  
negative.code:      
              deltap = (fpfine1(jj1,mq) + fpfine1(jj2,mq)) -
       &               (eff1(jj1,mq,1) + eff1(jj2,mq,1))
               
  c           # Put the same value in four ghost cells;  grab the first
  c           # one that shows up in the transformation.          
              do jj = jj1,jj2
  