矩阵.A

y = mat([1,2,5,6])
y1 = mat([4,8,7,5])

def rssError(y_label,y_pred):
    return sqrt(sum(pow(y_label - y_pred,2)))

#对于矩阵是无法直接运用上述的函数，必须加.A

print(rssError(y.A,y1.A)) #7.0710678118654755

print(rssError(y,y1))
# File "E:/software/python实现算法/888.py", line 27, in <module>
#     print(rssError(y,y1))
#   File "E:/software/python实现算法/888.py", line 24, in rssError
#     return sqrt(sum(pow(y_label - y_pred,2)))
#   File "C:\lixiangquan\lib\site-packages\numpy\matrixlib\defmatrix.py", line 322, in __pow__
#     return matrix_power(self, other)
#   File "C:\lixiangquan\lib\site-packages\numpy\matrixlib\defmatrix.py", line 139, in matrix_power
#     raise ValueError("input must be a square array")
# ValueError: input must be a square array