anchor.diff:  ! Minimize model smoothness
   if (smoothing_constant.gt.0.0d0) then
       call lsqr_load_smooth(A,b,nrows,ncols,smoothing_constant,ptr_smooth)
  +endif
  +
  +! Apply constraints
  +if (slip_constraint_file.ne.'none') then
  +    call lsqr_load_slip_constraint(A,b,nrows,ncols,ptr_stress,ptr_smooth)
   endif
   
   if (verbosity.ge.3) then
  
positive.code: ! Add equations to model matrix to minimize the curvature (second derivative)
  ! of the solution to Ax = b with weighting factor smooth.
  !----
  use command_line, only : rake_file
  use arrays, only : nfaults, nsmooth, smoothing_pointers, smoothing_neighbors
  implicit none
  ! I/O variables
  integer :: nrows, ncols, ptr_smooth
  double precision :: A(nrows,ncols), b(nrows,1), smoothing_constant
  ! Local variables
  integer :: i, j, ifault, nneighbor, ineighbor, neighbor
  
  ! Read smoothing element linking file and load into A
  do i = 1,nsmooth
  
negative.code: ! Local variables
  integer :: i, j
  
  if (verbosity.ge.2) then
      write(stderr,'(A)') 'Finished lsqr_load_stress()'
  endif
  
  