对交叉熵的理解
参考 https://blog.csdn.net/tsyccnh/article/details/79163834
参考https://charlesliuyx.github.io/2017/09/11/%E4%BB%80%E4%B9%88%E6%98%AF%E4%BF%A1%E6%81%AF%E7%86%B5%E3%80%81%E4%BA%A4%E5%8F%89%E7%86%B5%E5%92%8C%E7%9B%B8%E5%AF%B9%E7%86%B5/ 【直观详解】信息熵、交叉熵和相对熵
