anchor.diff:    call elem% create_fixed(box_group, 'edges', L*1.d0)
     call h5gclose_f(box_group, error)
   
  +  call e_solvent% create_time(colloids_group, 'position', solvent% pos, ior(H5MD_TIME, H5MD_STORE_TIME))
  +
     call solvent% sort(solvent_cells)
   
     call neigh% init(N_colloids, 300)
  
positive.code:   end do
    close(12)
  
    do i = 1, 1000
  
       call solvent% random_placement(L*1.d0)
       call solvent% sort(solvent_cells)
       call neigh% update_list(colloids, solvent, 1.4d0, solvent_cells)
  
    end do
  
  
negative.code: 
    type(h5md_file_t) :: datafile
    type(h5md_element_t) :: elem
    type(h5md_element_t) :: e_solvent
    integer(HID_T) :: colloids_group, box_group
  
    integer, parameter :: N = 1000
  