anchor.diff:  
     call solvent_cells%count_particles(solvent% pos)
   
  -  print *, sum(solvent_cells%cell_count)
  -  print *, solvent_cells%cell_count
  -  print *, solvent_cells%cell_start(1), solvent_cells%cell_start(solvent_cells%N)
  +  call datafile% create('test_data.h5', 'RMPCDMD:try_all', '0.0 dev', 'Pierre de Buyl')
  +  call h5gcreate_f(datafile% particles, 'colloids', colloids_group, error)
  +
  +  call h5gcreate_f(colloids_group, 'box', box_group, error)
  +  call h5md_write_attribute(box_group, 'dimension', 3)
  +  call h5md_write_attribute(box_group, 'boundary', ['periodic', 'periodic', 'periodic'])
  +  call elem% create_fixed(box_group, 'edges', L*1.d0)
  +  call h5gclose_f(box_group, error)
   
     call solvent% sort(solvent_cells)
   
  
positive.code:   end do
    close(12)
  
  end program try_all
  
negative.code:   use hilbert
    use neighbor_list
    use interaction
    use hdf5
    use h5md_module
    implicit none
  
    type(cell_system_t) :: solvent_cells
  