https://zhuanlan.zhihu.com/p/26614750
https://blog.csdn.net/zengxiantao1994/article/details/72787849
https://blog.csdn.net/red_stone1/article/details/80735068
极大似然估计与交叉熵损失函数
原文：https://www.cnblogs.com/bingws/p/10863490.html
