@Test
  public void test3() {
    RandomUtil.getInstance().setSeed(49293843L);

    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.setShowErrorTerms(true);

    Node e1 = graph.getExogenous(x1);
    Node e2 = graph.getExogenous(x2);
    Node e3 = graph.getExogenous(x3);
    Node e4 = graph.getExogenous(x4);
    Node e5 = graph.getExogenous(x5);

    graph.addDirectedEdge(x1, x3);
    graph.addDirectedEdge(x1, x2);
    graph.addDirectedEdge(x2, x3);
    graph.addDirectedEdge(x3, x4);
    graph.addDirectedEdge(x2, x4);
    graph.addDirectedEdge(x4, x5);
    graph.addDirectedEdge(x2, x5);
    graph.addDirectedEdge(x5, x1);

    GeneralizedSemPm pm = new GeneralizedSemPm(graph);

    List<Node> variablesNodes = pm.getVariableNodes();
    print(variablesNodes);

    List<Node> errorNodes = pm.getErrorNodes();
    print(errorNodes);

    try {
      pm.setNodeExpression(x1, "cos(b1) + a1 * X5 + E_X1");
      pm.setNodeExpression(x2, "a2 * X1 + E_X2");
      pm.setNodeExpression(x3, "tan(a3*X2 + a4*X1) + E_X3");
      pm.setNodeExpression(x4, "0.1 * E^X2 + X3 + E_X4");
      pm.setNodeExpression(x5, "0.1 * E^X4 + a6* X2 + E_X5");
      pm.setNodeExpression(e1, "U(0, 1)");
      pm.setNodeExpression(e2, "U(0, 1)");
      pm.setNodeExpression(e3, "U(0, 1)");
      pm.setNodeExpression(e4, "U(0, 1)");
      pm.setNodeExpression(e5, "U(0, 1)");

      GeneralizedSemIm im = new GeneralizedSemIm(pm);

      print(im);

      DataSet dataSet = im.simulateDataNSteps(1000, false);

      //            System.out.println(dataSet);

      double[] d1 = dataSet.getDoubleData().getColumn(0).toArray();
      double[] d2 = dataSet.getDoubleData().getColumn(1).toArray();

      double cov = StatUtils.covariance(d1, d2);

      assertEquals(-0.002, cov, 0.001);
    } catch (ParseException e) {
      e.printStackTrace();
    }
  }