20170227. 牛頓法，Hessian矩陣、雅克比矩陣

1. 嗨森矩陣和雅克比矩陣

http://jacoxu.com/jacobian矩陣和hessian矩陣/

Hessian矩陣的逆求解不便

2. 各種擬牛頓法 Quasi-Newton Methods

http://www.cnblogs.com/richqian/p/4535550.html

http://blog.csdn.net/acdreamers/article/details/44664941