非线性曲线拟合是已知输入向量xdata和输出向量ydata，并且知道输入与输出的函数关系为ydata=F(x, xdata)，但不知道系数向量x。今进行曲线拟合，求x使得输出的如下最小二乘表达式成立：

min Σ(F(x,xdatai)-ydatai)^2-Nonlinear curve fitting is a known input and output vectors xdata vector ydata, and know the relationship between the input and output functions for ydata = F (x, xdata), but do not know the coefficient vector x. As least-squares curve fitting expression today, find x such that the output of the establishment:

min Σ (F (x, xdatai)-ydatai) ^ 2