10.6 Gradient_regresion.py 文件源码

def test_GradientBoostingRegressor_subsample(*data):
    '''
    test the performance with different subsample
    :param data:    train_data, test_data, train_value, test_value
    :return:  None
    '''
    X_train,X_test,y_train,y_test=data
    fig=plt.figure()
    ax=fig.add_subplot(1,1,1)
    subsamples=np.linspace(0.01,1.0,num=20)
    testing_scores=[]
    training_scores=[]
    for subsample in subsamples:
            regr=ensemble.GradientBoostingRegressor(subsample=subsample)
            regr.fit(X_train,y_train)
            training_scores.append(regr.score(X_train,y_train))
            testing_scores.append(regr.score(X_test,y_test))
    ax.plot(subsamples,training_scores,label="Training Score")
    ax.plot(subsamples,testing_scores,label="Training Score")
    ax.set_xlabel("subsample")
    ax.set_ylabel("score")
    ax.legend(loc="lower right")
    ax.set_ylim(-1,1.05)
    plt.suptitle("GradientBoostingRegressor")
    plt.show()