xj = m_JRand.nextDouble(); yj = m_JRand.nextDouble();
xj = m_JRand.nextGaussian(); yj = m_JRand.nextGaussian();
    private void updatePturb() {      double xj=0;      double yj=0;      for (int i=0;i<m_plotInstances.numInstances();i++) {	if (m_plotInstances.instance(i).isMissing(m_xIndex) ||	    m_plotInstances.instance(i).isMissing(m_yIndex)) {	} else {	  if (m_JitterVal > 0) {	    xj = m_JRand.nextDouble();	    yj = m_JRand.nextDouble();	  }	  m_pointLookup[i][3] = pturbX(m_pointLookup[i][0],xj);	  m_pointLookup[i][4] = pturbY(m_pointLookup[i][1],yj);	}      }    }