LM算法的简要描述。LM算法是一种定位多变量函数最小值的迭代技术，是解决非线性最小二乘问题的基本技术之一。-The Levenberg-Marquardt(LM)algorithm is an iterative technique that locates the minimum of a multivariate function that is expressed as the sum of squares of non-linear real-valued functions[4