code: public static <D>
  	ScoreAssociation<D> scoreSad( Class<D> tupleType ) {
  		if( TupleDesc_F64.class.isAssignableFrom(tupleType) ) {
  			return (ScoreAssociation)new ScoreAssociateSad_F64();
  		} else if( tupleType == TupleDesc_F32.class ) {
  			return (ScoreAssociation)new ScoreAssociateSad_F32();
  		} else if( tupleType == TupleDesc_U8.class ) {
  			return (ScoreAssociation)new ScoreAssociateSad_U8();
  		} else if( tupleType == TupleDesc_S8.class ) {
  			return (ScoreAssociation)new ScoreAssociateSad_S8();
  		} else {
  			throw new IllegalArgumentException("SAD score not supported for type "+tupleType.getSimpleName());
  		}
  	}
docs: Scores features based on Sum of Absolute Difference (SAD).
  
  @param tupleType Type of descriptor being scored
  @return SAD scorer