anchor.diff:        open(fid_tot,file  = fname_tot, action='write',&
             status = 'replace', iostat = ios)
         if (ios /= 0) then
  -      write(*,*)"error while opening file", fname_tot
  -      stop
  +         write(*,*)"Error while opening the ", fname_tot," file."
  +         stop
         endif
   
         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) 
  +
  +        call variables(temp_real(j), sigma_real(j), omega, f, optical_depth, tau_eff)
  +
           temp_real(j)  =  temp_real(j) * state_0%T_0
           sigma_real(j) =  sigma_real(j) * state_0%S_0
  -
  -        call variables(temp_real(j), sigma_real(j), omega, f, optical_depth, tau_eff)
  -
  -        ! call save_data(fid_tot, fname_tot, nb_it, file_length, sigma_real(j), temp_real(j), tau_eff)
   
           write(fid_tot,fmt = '(3(e16.6e2))') sigma_real(j), temp_real(j), tau_eff
   
  
positive.code:       ! ADIMENSIONED critical T and S [OUTPUT]
  
        temperature(k) = temp_c_thick
        s(k)           = sigma_c_thick
  
        ! DIMENSIONED critical T and S
        temp_thick(k)  =  temp_c_thick * state_0%T_0
  
negative.code:     character(len = 64)                                    :: fname_tot
      integer                                                :: fid_tot
      integer                                                :: ios
  
   ! For the critical points
      integer                                                :: index_fcp
      real(kind = x_precision)                               :: sigma_c_thick
  