anchor.diff:  
     call h5gclose_f(solvent_group, error)
   
  +  call tz% norm()
  +  call elem% create_fixed(datafile% observables, 'tz', tz% data)
  +  call elem% create_fixed(datafile% observables, 'tz_count', tz% count)
  +
  +  call h5gclose_f(datafile% observables, error)
  +
     call datafile% close()
   
     call h5close_f(error)
  
positive.code: program setup_fluid
    use cell_system
    use particle_system
    use hilbert
  
negative.code:      call e_solvent_v% append(solvent% vel, i, i*1.d0)
  
       call solvent_cells%count_particles(solvent% pos)
       write(13,*) compute_temperature(solvent, solvent_cells, tz), sum(solvent% vel**2)/(3*solvent% Nmax), v_com
  
    end do
  
    call e_solvent% close()
  