| import torch.nn as nn | |
| from attention import MultiHeadedAttention | |
| from transformer_component import SublayerConnection, PositionwiseFeedForward | |
| class TransformerBlock(nn.Module): | |
| """ | |
| Bidirectional Encoder = Transformer (self-attention) | |
| Transformer = MultiHead_Attention + Feed_Forward with sublayer connection | |
| """ | |
| def __init__(self, hidden, attn_heads, feed_forward_hidden, dropout): | |
| """ | |
| :param hidden: hidden size of transformer | |
| :param attn_heads: head sizes of multi-head attention | |
| :param feed_forward_hidden: feed_forward_hidden, usually 4*hidden_size | |
| :param dropout: dropout rate | |
| """ | |
| super().__init__() | |
| self.attention = MultiHeadedAttention(h=attn_heads, d_model=hidden) | |
| self.feed_forward = PositionwiseFeedForward(d_model=hidden, d_ff=feed_forward_hidden, dropout=dropout) | |
| self.input_sublayer = SublayerConnection(size=hidden, dropout=dropout) | |
| self.output_sublayer = SublayerConnection(size=hidden, dropout=dropout) | |
| self.dropout = nn.Dropout(p=dropout) | |
| def forward(self, x, mask): | |
| x = self.input_sublayer(x, lambda _x: self.attention.forward(_x, _x, _x, mask=mask)) | |
| x = self.output_sublayer(x, self.feed_forward) | |
| return self.dropout(x) | |