anchor.diff:        write(fid_tot,'(3(A16))') 'Surface_density', 'Temperature', 'Optical_depth'
   
         do j = 1, nb_it
  -        temp_real(j)  =  temp_real(j) 
  -        sigma_real(j) =  sigma_real(j) 
  +        temp_real(j)  =  temp_real(j)
  +        sigma_real(j) =  sigma_real(j)
   
           call variables(temp_real(j), sigma_real(j), omega, f, optical_depth, tau_eff)
   
  
positive.code: 
        call display_critical_points(sigma_c_thin, temp_c_thin, sigma_c_thick, temp_c_thick, k)
  
  
        ! Saving the DIMENSIONED values of Sigma and T for the S curve in a file
        write(number_of_cell,'(I5.5)') k
        fid_tot = 22 + k
        fname_tot = 's_curves/Temperature_Sigma_'//trim(number_of_cell)//'_tot.dat'
        
        open(fid_tot,file  = fname_tot, action='write', status = 'replace', iostat = ios)
        if (ios /= 0) then
          write(*,*)"Error while opening the ", fname_tot," file."
  
negative.code:     real(kind = x_precision),intent(in) :: sigma_c_thick
      real(kind = x_precision),intent(in) :: temp_c_thick
      integer                 ,intent(in) :: k
  
      !------------------------------------------------------------------------
  
      write(*,*)'**** Critical Point',k,'********'
      write(*,*)'****************************************'
      write(*,"(' Optically thin (T,sigma) :',1p,E12.4,4x,1p,E12.4)")temp_c_thin,sigma_c_thin
  