anchor.diff:  
           ! returns u_perturb and v_perturb
       end subroutine linear_perturbation
  -    
  +
       !>----------------------------------------------------------
       !! Compute linear wind perturbations to U and V and add them back to the domain
       !!
  
positive.code:         type(linear_theory_type), intent(inout) :: lt_data
          integer, intent(in) :: nx, ny
          real,    intent(in) :: dx
          
          integer(C_SIZE_T) :: n_elements
          real :: gain, offset
          integer :: i
  
          
          allocate(lt_data%k(nx,ny))
          allocate(lt_data%l(nx,ny))
          allocate(lt_data%kl(nx,ny))
  
negative.code:     integer :: n_spd_values=10
  
      complex,parameter :: j= (0,1)
  
      real, parameter :: SMALL_VALUE = 1e-15
  
  contains
  