说明：  根据论文《Products of spline》一文的描述，两个B-Spline的乘积可以由一个更高次的B-Spline表示,本程序提供通过B样条相乘来实现了B样条升阶的另外一种方法
(As from a paper named "Products of spline",the product of two B-Spline can be represented in an arbitrary higher B-Splie.This program offer another method of increasing order of B-Spline by using the product of the B-Spline)