anchor.diff:        integer::i = 0
   
         do i = 1,index_scp
  -         sigma_real(i) = sigma_real_1(i)
  -         temp_real(i) = temp_real_1(i)
  +         sigma_real(i) = sigma_real_thick(i)
  +         temp_real(i) = temp_real_thick(i)
         enddo
         do i = index_scp + 1, nb_it
  -         sigma_real(i) = sigma_real_0(i)
  -         temp_real(i) = temp_real_1(i)
  +         sigma_real(i) = sigma_real_thin(i)
  +         temp_real(i) = temp_real_thick(i)
         enddo
   
       end subroutine build_s_curve
  
positive.code:             ! write(*,*)index_fcp
  
      ! do i = index_fcp, nb_it
      !   write(*,*)sigma_real_0(i), sigma_real_1(i)
      !   write(*,*)(dabs(sigma_real_1(i) - sigma_real_0(i+1)))
      ! end do
  
      do i = index_fcp, nb_it - 1
  
         if(dabs(sigma_real_1(i) - sigma_real_0(i+1)) .lt. eps2)then
            index_scp = i
            ! sigma_c_thin = (sigma_real_1(i) + sigma_real_0(i+1))/2._x_precision
            sigma_c_thin =  sigma_real_0(i+1)
  
            temp_c_thin = temp_real_1(i)
         end if
      enddo
  
  
negative.code: 
            call variables(temp, sigma, omega, f, optical_depth)
  
            temp_t_thin(i)   =  temp
            sigma_t_thin(i)  =  sigma
  
  
           ! do l          = 1, nb_it
  