Add SeqDropout

[hfxunlp]

I change the Dropout implentation of Torch/nn, get a dropout module that could be used for SeqLSTM, SeqGRU and SeqBRNN. the whole sequence will share the same mask which is diferrent from nn.Dropout.

[hfxunlp]

I am not good at both coding and english, I appreciate any kinds of your help.

[JoostvDoorn]

👍 I think this module does not need to be restricted to SeqLSTM, SeqGRU etc. Also it would be helpful if this module could support :remember('both').

For anyone interested why you want to do this, read: http://www.stat.berkeley.edu/~tsmoon/files/Conference/asru2015.pdf (edit: sorry for some reason I posted the wrong link here)

[hfxunlp]

@JoostvDoorn Thank you for your support. This module was considered to used before SeqRNN implementation, and I'm not clear how to implement remember in this module, I just used it like that: nn.Sequential():add(nn.SeqDropout()):add(nn.SeqGRU(128,128)) In my understanding, remember was a method of AbstractSequencer and maybe there should be some changes in SeqLSTM, SeqGRU etc, but sorry for I do not know how to make it work, the codes were to hard for me.

[JoostvDoorn]

That's okay, someone else (or me) should be able to implement remember for this fairly easily. Regarding it being only for SeqGRU etc., you can use it like this nn.Sequential():add(nn.SeqDropout(0.2)):add(nn.Sequencer(nn.GRU(128,128))). So we do not need to restrict this in the documentation.

[hfxunlp]

@JoostvDoorn Thank you for your help, I do not have enough experience in this area, your advise is very helpful for me.