import numpy as np
def R_Square(train_X,test_x,train_Y,test_y,functin=None):
    y,p_y = XGBRegressor_model(train_X,test_x,train_Y,test_y)
    n = test_y.size 
    one_vector = np.ones(n)
    """$$ \bar{y}=\frac{1}{n} \sum_{i=1}^{n} y_{i} $$"""
    y_ = (1/n)*y.dot(one_vector)
    ei = y-p_y
    SStot = ((y-y_)**2).dot(one_vector)
    SSreg = ((p_y - y_)**2).dot(one_vector)
    SSres = ((y-p_y)**2).dot(one_vector)
    R_2 = 1-SSres/SStot
    title = {
    
    "观测数据均值":y_,"残差":ei,"总平方和":SStot,"回归平方和":SSreg,"残差平方和":SSres,"可决系数":R_2}
    return title