Automatic differential reference

1. Automatic differentiation (Automatic Differentiation) brief introduction （https://blog.csdn.net/aws3217150/article/details/70214422）
2. Lecture 4: Automatic Differentiation （https://zhuanlan.zhihu.com/p/65488534）
3. DL | Automatic differentiation （ AutoDiff） principle ︎（https://zhuanlan.zhihu.com/p/60048471）
4. Automatic differentiation autodiff Open source library （https://github.com/autodiff/autodiff）