中文说明：DFP算法Davidon-Fletcher-Powell 是解决无约束多维极值问题的一种算法，它是拟牛顿算法的一种，可以用于求解作为迭代的初值，多数情况下可以直接求解，并且逼近速度较快
English Description：
Davidon-Fletcher-Powell DFP algorithm is an algorithm for solving unconstrained multi-extremum problems, it is a kind of quasi-Newton algorithms can be used to solve as the initial value of the iteration, and in most cases can be solved, and fast approaching speed