anchor.diff:    real(kind = x_precision) function dichotomy(k, S_min, S_max, eps, T, optical_depth)
       implicit none
   
  -    real(kind = x_precision),intent(inout) :: S_min,S_max
  -    real(kind = x_precision),intent(in)    :: eps
  -    real(kind = x_precision),intent(in)    :: T
  -    integer,                 intent(in)    :: k
  -    integer,                 intent(in)    :: optical_depth
  -
  -    integer                                :: j
  -    real(kind = x_precision)               :: tau_eff
  -    real(kind = x_precision)               :: Smin
  -    real(kind = x_precision)               :: Smax
  -    real(kind = x_precision)               :: f_min
  -    real(kind = x_precision)               :: f_max
  -    real(kind = x_precision)               :: f_center
  -    real(kind = x_precision)               :: S_center
  +    real(kind = x_precision),intent(in) :: S_min, S_max
  +    real(kind = x_precision),intent(in) :: eps
  +    real(kind = x_precision),intent(in) :: T
  +    integer,                 intent(in) :: k
  +    integer,                 intent(in) :: optical_depth
  +
  +    integer                             :: j
  +    real(kind = x_precision)            :: tau_eff
  +    real(kind = x_precision)            :: Smin
  +    real(kind = x_precision)            :: Smax
  +    real(kind = x_precision)            :: f_min
  +    real(kind = x_precision)            :: f_max
  +    real(kind = x_precision)            :: f_center
  +    real(kind = x_precision)            :: S_center
   
       !-------------------------------------------------------------------------
       ! N-> Number of iterations for the dichotomy
  
positive.code:         ! Optical thick case (tau >= 1)
          optical_depth = 1
  
          ! S range
          Smin          = S_min
          Smax          = S_max
  
          ! S found with the dichotomy approach
          sigma_t_thick(i) = dichotomy(k, Smin, Smax, eps, temperature(i), optical_depth)
  
          ! Optical thin case (tau < 1)
          optical_depth = 0
  
          ! S range
          Smin          = S_min
          Smax          = S_max
  
          ! S found with the dichotomy approach
          sigma_t_thin(i)  = dichotomy(k, Smin, Smax, eps, temperature(i), optical_depth)
  
        enddo
  
  
negative.code:     !------------------------------------------------------------------------
      integer                                                :: i,j,k
  
      ! For variables
      real(kind = x_precision)                               :: f              ! Q+ - Q-
      real(kind = x_precision)                               :: tau_eff        ! Effective optical depth
      integer                                                :: optical_depth  ! Indicator for the optical thickness
  