@Test
  public void test2() {
    RandomUtil.getInstance().setSeed(2999983L);

    int sampleSize = 1000;

    List<Node> variableNodes = new ArrayList<>();
    ContinuousVariable x1 = new ContinuousVariable("X1");
    ContinuousVariable x2 = new ContinuousVariable("X2");
    ContinuousVariable x3 = new ContinuousVariable("X3");
    ContinuousVariable x4 = new ContinuousVariable("X4");
    ContinuousVariable x5 = new ContinuousVariable("X5");

    variableNodes.add(x1);
    variableNodes.add(x2);
    variableNodes.add(x3);
    variableNodes.add(x4);
    variableNodes.add(x5);

    Graph _graph = new EdgeListGraph(variableNodes);
    SemGraph graph = new SemGraph(_graph);
    graph.addDirectedEdge(x1, x3);
    graph.addDirectedEdge(x2, x3);
    graph.addDirectedEdge(x3, x4);
    graph.addDirectedEdge(x2, x4);
    graph.addDirectedEdge(x4, x5);
    graph.addDirectedEdge(x2, x5);

    SemPm semPm = new SemPm(graph);
    SemIm semIm = new SemIm(semPm);
    DataSet dataSet = semIm.simulateData(sampleSize, false);

    print(semPm);

    GeneralizedSemPm _semPm = new GeneralizedSemPm(semPm);
    GeneralizedSemIm _semIm = new GeneralizedSemIm(_semPm, semIm);
    DataSet _dataSet = _semIm.simulateDataMinimizeSurface(sampleSize, false);

    print(_semPm);

    //        System.out.println(_dataSet);

    for (int j = 0; j < dataSet.getNumColumns(); j++) {
      double[] col = dataSet.getDoubleData().getColumn(j).toArray();
      double[] _col = _dataSet.getDoubleData().getColumn(j).toArray();

      double mean = StatUtils.mean(col);
      double _mean = StatUtils.mean(_col);

      double variance = StatUtils.variance(col);
      double _variance = StatUtils.variance(_col);

      assertEquals(mean, _mean, 0.3);
      assertEquals(1.0, variance / _variance, .2);
    }
  }