double div = Math.sqrt(super.eval(id1, id1, inst1) * super.eval(id2, id2, m_data.instance(id2))); if(div != 0){
double div = Math.sqrt(super.eval(id1, id1, inst1) * ((m_keys != null) ? super.eval(id2, id2, m_data.instance(id2)) : super.eval(-1, -1, m_data.instance(id2))));  if(div != 0){
  public double eval(int id1, int id2, Instance inst1)     throws Exception {	    double div = Math.sqrt(super.eval(id1, id1, inst1) * 			   super.eval(id2, id2, m_data.instance(id2)));    if(div != 0){      return super.eval(id1, id2, inst1) / div;    } else {      return 0;    }  }