说明：  NumPy系统是Python的一种开源的数值计算扩展。这种工具可用来存储和处理大型矩阵，比Python自身的嵌套列表（nested list structure)结构要高效的多（该结构也可以用来表示矩阵（matrix））
(Numpy system is an open-source numerical calculation extension of Python. This tool can be used to store and process large matrices, which is much more efficient than Python's nested list structure structure (which can also be used to represent matrices))