请详细写出所有的python代码(含详细的文字注释)
时间: 2024-12-06 21:25:24 浏览: 10
为了帮助您理解,我会提供一个基础的Python代码示例,包括BERT+TextCNN模型的搭建以及基本的数据预处理。这里我们假设已经安装了`transformers`库(包含了Hugging Face的BERT模型),`torch`库(深度学习框架),以及其他必要的库。我们将使用PyTorch实现这个模型。
首先,导入所需的库:
```python
# 导入库
import torch
from torch import nn
from transformers import BertTokenizer, BertModel
from sklearn.model_selection import train_test_split
from collections import Counter
```
接下来,定义模型类:
```python
class BERTTextCNN(nn.Module):
def __init__(self, bert_model_name, num_classes, max_len=512):
super(BERTTextCNN, self).__init__()
# 初始化BERT模型
self.bert = BertModel.from_pretrained(bert_model_name)
self.dropout = nn.Dropout(0.2) # 防止过拟合
self.pooler = nn.Linear(self.bert.config.hidden_size, num_classes) # 输出层
# TextCNN部分
self.conv1d_layers = nn.ModuleList([
nn.Conv1d(in_channels=self.bert.config.hidden_size,
out_channels=num_filters,
kernel_size=kernel_size) for kernel_size in [3, 4, 5]
])
self.classifier = nn.Sequential(
nn.MaxPool1d(max_len), # 考虑整个句子
self.dropout,
nn.Linear(len(self.conv1d_layers) * num_filters, num_classes) # 统一所有过滤后的维度
)
def forward(self, input_ids, attention_mask):
_, pooled_output = self.bert(input_ids=input_ids, attention_mask=attention_mask)
pooled_output = self.dropout(pooled_output)
# 对每个conv层的输出求和,然后扁平化
conv_outputs = [nn.ReLU()(conv_layer(pooled_output.permute(0, 2, 1))) for conv_layer in self.conv1d_layers]
conv_outputs = torch.cat(conv_outputs, dim=-1)
# 取最大池化值,获得句子级别的特征
max_pool = torch.max(conv_outputs, dim=1)[0]
# 输出层分类
return self.classifier(max_pool)
```
然后,处理数据并定义训练和预测函数:
```python
def preprocess_data(texts, labels, tokenizer, max_len, pad_token_id, label_encoder):
inputs = tokenizer(texts, truncation=True, padding='max_length', max_length=max_len, return_tensors="pt")
labels = label_encoder(labels)
return inputs['input_ids'], inputs['attention_mask'], labels
def train(model, data_loader, optimizer, device, loss_fn):
model.train()
total_loss = 0
for batch in data_loader:
input_ids, attention_mask, labels = [t.to(device) for t in batch]
outputs = model(input_ids, attention_mask)
loss = loss_fn(outputs, labels)
optimizer.zero_grad()
loss.backward()
optimizer.step()
total_loss += loss.item()
return total_loss / len(data_loader)
def predict(model, texts, tokenizer, max_len, device):
with torch.no_grad():
input_ids, _, _ = preprocess_data(texts, None, tokenizer, max_len, model.config.pad_token_id, None)
input_ids = input_ids.to(device)
attention_mask = torch.ones_like(input_ids).to(device)
probabilities = model(input_ids, attention_mask).softmax(dim=1)
return probabilities.tolist()
# 数据加载、分割、编码和模型训练略...
```
以上代码只是一个基础框架,实际应用中还需要细化数据预处理过程(如处理时间特征),划分训练集和验证集,设置损失函数(如交叉熵)、优化器(如Adam),以及训练循环。同时,记得调整超参数以适应您的具体任务需求。
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