基于pytorch搭建cnn-lstm-attention
时间: 2023-09-01 18:10:42 浏览: 131
下面是基于PyTorch搭建CNN-LSTM-Attention的示例代码:
```python
import torch
import torch.nn as nn
import torch.nn.functional as F
class CNN_LSTM_Attention(nn.Module):
def __init__(self, vocab_size, embedding_dim, hidden_dim, num_layers, dropout, output_dim, kernel_sizes, num_filters, bidirectional):
super().__init__()
# 定义嵌入层
self.embedding = nn.Embedding(vocab_size, embedding_dim)
# 定义卷积层
self.convs = nn.ModuleList([
nn.Conv2d(in_channels=1, out_channels=num_filters, kernel_size=(fs, embedding_dim))
for fs in kernel_sizes
])
# 定义LSTM层
self.lstm = nn.LSTM(num_filters * len(kernel_sizes), hidden_dim, num_layers=num_layers, dropout=dropout, bidirectional=bidirectional)
# 定义attention层
self.attention = nn.Linear(hidden_dim * 2 if bidirectional else hidden_dim, 1)
# 定义全连接层
self.fc = nn.Linear(hidden_dim * 2 if bidirectional else hidden_dim, output_dim)
# 定义dropout
self.dropout = nn.Dropout(dropout)
def forward(self, text):
# text: [batch_size, sent_len]
# 嵌入
embedded = self.embedding(text) # embedded: [batch_size, sent_len, emb_dim]
# 变形
embedded = embedded.unsqueeze(1) # embedded: [batch_size, 1, sent_len, emb_dim]
# 卷积
conved = [F.relu(conv(embedded)).squeeze(3) for conv in self.convs] # conved: [batch_size, num_filters, sent_len - fs + 1]
# 池化
pooled = [F.max_pool1d(conv, conv.shape[2]).squeeze(2) for conv in conved] # pooled: [batch_size, num_filters]
# 拼接
cat = self.dropout(torch.cat(pooled, dim=1)) # cat: [batch_size, num_filters * len(kernel_sizes)]
# LSTM
output, (hidden, cell) = self.lstm(cat.unsqueeze(0)) # output: [1, batch_size, hidden_dim * num_directions], hidden: [num_layers * num_directions, batch_size, hidden_dim], cell: [num_layers * num_directions, batch_size, hidden_dim]
# attention
attention_weights = F.softmax(self.attention(output.squeeze(0)), dim=1) # attention_weights: [batch_size, 1, hidden_dim * num_directions]
attention_output = torch.bmm(attention_weights.transpose(1, 2), output.transpose(0, 1)).squeeze(1) # attention_output: [batch_size, hidden_dim * num_directions]
# 全连接
return self.fc(self.dropout(attention_output))
```
此模型采用了CNN-LSTM-Attention结构,其中包含了嵌入层、卷积层、LSTM层、attention层和全连接层。在前向传播过程中,先将输入的文本通过嵌入层转换为词向量,然后通过多个不同大小的卷积核提取文本的不同特征,接着通过最大池化操作将各个特征的值取最大,最后将各个特征拼接起来输入到LSTM层中进行序列建模。在LSTM层之后,通过attention层对LSTM层的输出进行加权平均,得到文本的表示,最后通过全连接层输出分类结果。
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