最小二乘曲线拟合的一个类，用来实现一元线性回归的负荷预测

把积分变成求和，再以所得到关于点集正交的多项式作基求最小二乘的拟合曲线-The integral into a sum of them, and then got on the point set of orthogonal polynomials for least-squares fitting curve of the base demand

利用此函数可以在最小二乘意义上解决非线性曲线拟合（数据 拟合）问题。也就是说，给定输入数据xdata，以及观测的输出数据ydata，找到系数x，使 得函数F(x，xdata)能够最好的拟合向量值-MLS method not only can be applied for the purpose of curve (or surface) fitting, but also curve (or surface) interpolation when compactly supp