二维曲线拟合就是根据输入数据的坐标（xi,yi），即X数组和Y数组，找出yi和xi的函数关系y=f(x)。对于不同的对象-Two-dimensional curve fitting is based on the coordinates of the input data (xi, yi), the X array and Y array, to identify the function of yi and xi y = f (x). For different objects