anchor.diff:  
     real(WP), parameter :: ARTIFICIAL_VISCOSITY = 1.0e-2_WP
     real(WP), parameter :: VORTICITY_COEFFICIENT = 1.0e-4_WP
  -  logical,  parameter :: USE_VORTICITY_CONFINEMENT = .false.
  +  logical,  parameter :: USE_VORTICITY_CONFINEMENT = .true.
   
     real(WP) :: PRESSURE_RADIUS_FACTOR
   
  
positive.code:     ! Floor
      if(cpy(i) .lt. 0.0_WP) then
        cpy(i) = 0.0_WP
        cvy(i) = -cvy(i)
      end if
  
      ! Left Wall
      if(cpx(i) .lt. -BOX_SIZE) then
        cpx(i) = -BOX_SIZE
        cvx(i) = -cvx(i)
      end if
  
      ! Right Wall
      if(cpx(i) .gt. BOX_SIZE) then
        cpx(i) = BOX_SIZE
        cvx(i) = -cvx(i)
      end if
  
      ! Back Wall
      if(cpz(i) .lt. -BOX_SIZE) then
        cpz(i) = -BOX_SIZE
        cvz(i) = -cvz(i)
      end if
  
      ! Front Wall
      if(cpz(i) .gt. BOX_SIZE) then
        cpz(i) = BOX_SIZE
        cvz(i) = -cvz(i)
      end if
  
    end do
  
    return
  end subroutine particle_jiggle
  
  subroutine compute_omega
    use state
  
negative.code:   integer :: i, j, l, nb
    real(WP) :: sx, sy, sz
    real(WP) :: dvx, dvy, dvz, k
    real(WP) :: r
  
    vx = cvx
    vy = cvy
  