code: protected double updateDistance(double currDist, double diff) {
      double	result;
      
      result  = currDist;
      result += diff * diff;
      
      return result;
    }
docs: Updates the current distance calculated so far with the new difference
  between two attributes. The difference between the attributes was
  calculated with the difference(int,double,double) method.
  
  @param currDist	the current distance calculated so far
  @param diff	the difference between two new attributes
  @return		the update distance
  @see		#difference(int, double, double)