def METHOD_NAME(h1,h2,log):
  cs1 = list(h1.chains())
  cs2 = list(h2.chains())
  if(len(cs1)==1): return
  print("Per chain (min/max/mean):", file=log)
  for c1, c2 in zip(cs1, cs2):
    label = c1.id
    r1 = c1.atoms().extract_xyz()
    r2 = c2.atoms().extract_xyz()
    d = flex.sqrt((r1 - r2).dot()).min_max_mean().as_tuple()
    print(label, ": %-8.3f %-8.3f %-8.3f"%d, file=log)
  print(file=log)