plt.subplot(2, 2, 3) plt.plot(X_test, f(X_test), "b") plt.scatter(X_train, y_train, c="b", s=20) plt.plot(X_test, rf_predict, "r", lw=2) plt.title("Random Forest, MSE = %.2f" % np.sum((y_test - rf_predict) ** 2))；
