torch.nn.GRU和torch.nn.GRUCell之间有什么区别

Question

torch.nn.GRU与torch.nn.GRUCell有什么区别？

例如为什么这里nn.GRU转换为nn.GRUCell？

https://github.com/erogol/WaveRNN/blob/master/models/wavernn.py#L108

https://github.com/erogol/WaveRNN/blob/master/models/wavernn.py#L153

https://github.com/erogol/WaveRNN/blob/master/models/wavernn.py#L227