Hello, I am implementing a seq2seq model and found a problem here:

encoder is a 2-layer bidirectional rnn, thus, the first dimension of last hidden state is 2*2=4
decoder is a 2-layer uni-directional rnn, I am wondering how does the encoder’s last hidden state pass to the decoder’s initial hidden state?
and, what if my decoder is a 1-layer (different from the num_layers of encoder), how does 2. work?