測試案例 1. [gdArray.py](https://github.com/ccc112b/py2cs/blob/master/03-%E4%BA%BA%E5%B7%A5%E6%99%BA%E6%85%A7/02-%E5%84%AA%E5%8C%96%E7%AE%97%E6%B3%95/02-%E6%B7%B1%E5%BA%A6%E5%AD%B8%E7%BF%92%E5%84%AA%E5%8C%96/03-%E6%A2%AF%E5%BA%A6%E4%B8%8B%E9%99%8D%E6%B3%95/gdArray.py) 2. [gdRegression.py](https://github.com/ccc112b/py2cs/blob/master/03-%E4%BA%BA%E5%B7%A5%E6%99%BA%E6%85%A7/02-%E5%84%AA%E5%8C%96%E7%AE%97%E6%B3%95/02-%E6%B7%B1%E5%BA%A6%E5%AD%B8%E7%BF%92%E5%84%AA%E5%8C%96/03-%E6%A2%AF%E5%BA%A6%E4%B8%8B%E9%99%8D%E6%B3%95/gdRegression.py) 參考 1. [gd.py](https://github.com/ccc112b/py2cs/blob/master/03-%E4%BA%BA%E5%B7%A5%E6%99%BA%E6%85%A7/02-%E5%84%AA%E5%8C%96%E7%AE%97%E6%B3%95/02-%E6%B7%B1%E5%BA%A6%E5%AD%B8%E7%BF%92%E5%84%AA%E5%8C%96/03-%E6%A2%AF%E5%BA%A6%E4%B8%8B%E9%99%8D%E6%B3%95/gd.py) 2. [梯度引擎](https://github.com/ccc112b/py2cs/tree/master/03-%E4%BA%BA%E5%B7%A5%E6%99%BA%E6%85%A7/02-%E5%84%AA%E5%8C%96%E7%AE%97%E6%B3%95/02-%E6%B7%B1%E5%BA%A6%E5%AD%B8%E7%BF%92%E5%84%AA%E5%8C%96/04-%E5%8F%8D%E5%82%B3%E9%81%9E%E7%AE%97%E6%B3%95/02-%E6%A2%AF%E5%BA%A6%E5%BC%95%E6%93%8E) 5. [engine.py](https://github.com/ccc112b/py2cs/blob/master/03-%E4%BA%BA%E5%B7%A5%E6%99%BA%E6%85%A7/02-%E5%84%AA%E5%8C%96%E7%AE%97%E6%B3%95/02-%E6%B7%B1%E5%BA%A6%E5%AD%B8%E7%BF%92%E5%84%AA%E5%8C%96/04-%E5%8F%8D%E5%82%B3%E9%81%9E%E7%AE%97%E6%B3%95/02-%E6%A2%AF%E5%BA%A6%E5%BC%95%E6%93%8E/micrograd/engine.py) 提示： 1. 用 backward() 函數取代 grad() ... 2. 所有值都要改用 Value() ...
