public static <T extends DC> Similarity getIndexedSim(Set<Pair<Pair<PT<Integer>,T>,Pair<PT<Integer>,T>>> done)
  { if(done!=null)
    { if(done.getNext()!=null)
      { return new Similarity(done.getFst().fst().delta(done.getFst().snd()).simi().getValue()+(getIndexedSim(done.getNext()).getValue()));
      }
      else
      { return new Similarity(done.getFst().fst().delta(done.getFst().snd()).simi().getValue());
      }  
    }
    else
    { return new Similarity(0.0);}  
  }