中文文本分类-Pytorch实现
- 🍨 本文为🔗365天深度学习训练营 中的学习记录博客
- 🍖 原作者:K同学啊
一、准备工作
1. 任务说明
本次使用Pytorch实现中文文本分类。主要代码与文本分类代码基本一致,不同的是本次任务使用了本地的中文数据,数据示例如下:
2.加载数据
import torch
import torch.nn as nn
import torchvision
from torchvision import transforms,datasets
import os,PIL,pathlib,warnings
warnings.filterwarnings("ignore") #忽略警告信息
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
device
输出:
device(type='cpu')
import pandas as pd
#加载自定义中文数据
train_data = pd.read_csv('./train.csv',sep='\t',header = None)
train_data.head()
输出:
#构造数据集迭代器
def coustom_data_iter(texts,labels):
for x,y in zip(texts,labels):
yield x,y
train_iter =coustom_data_iter(train_data[0].values[:],train_data[1].values[:])
二、数据预处理
#构建词典
from torchtext.data.utils import get_tokenizer
from torchtext.vocab import build_vocab_from_iterator
import jieba
#中文分词方法
tokenizer = jieba.lcut
def yield_tokens(data_iter):
for text,_ in data_iter:
yield tokenizer(text)
vocab = build_vocab_from_iterator(yield_tokens(train_iter),
specials=["<unk>"])
vocab.set_default_index(vocab["<unk>"]) #设置默认索引,如果找不到单词,则会选择默认索引
vocab(['我','想','看','和平','精英','上','战神','必备','技巧','的','游戏','视频'])
输出:
[2, 10, 13, 973, 1079, 146, 7724, 7574, 7793, 1, 186, 28]
label_name = list(set(train_data[1].values[:]))
print(label_name)
输出:
['FilmTele-Play', 'Alarm-Update', 'Weather-Query', 'Audio-Play', 'Radio-Listen', 'Travel-Query', 'Music-Play', 'Video-Play', 'HomeAppliance-Control', 'Calendar-Query', 'TVProgram-Play', 'Other']
text_pipeline = lambda x : vocab(tokenizer(x))
label_pipeline = lambda x : label_name.index(x)
print(text_pipeline('我想看和平精英上战神必备技巧的游戏视频'))
print(label_pipeline('Video-Play'))
输出:
[2, 10, 13, 973, 1079, 146, 7724, 7574, 7793, 1, 186, 28]
7
lambda表达式的语法为:lambda arguments: expression
其中arguments是函数的参数,可以有多个参数,用逗号分隔。expression是一个表达式,它定义了函数的返回值。
- text_pipeline函数: 将原始文本数据转换为整数列表,使用了之前构建的vocab词表和tokenizer分词器函数。具体步骤:
- 接受一个字符串x作为输入
- 使用tokenizer将其分词
- 将每个词在vocab词表中的索引放入一个列表返回
- label_pipeline函数: 将原始标签数据转换为整数,它接受一个字符串x作为输入,并使用 label_index.index(x) 方法获取x在label_name列表中的索引作为输出。
2.生成数据批次和迭代器
#生成数据批次和迭代器
from torch.utils.data import DataLoader
def collate_batch(batch):
label_list, text_list, offsets = [],[],[0]
for(_text, _label) in batch:
#标签列表
label_list.append(label_pipeline(_label))
#文本列表
processed_text = torch.tensor(text_pipeline(_text), dtype=torch.int64)
text_list.append(processed_text)
#偏移量
offsets.append(processed_text.size(0))
label_list = torch.tensor(label_list,dtype=torch.int64)
text_list = torch.cat(text_list)
offsets = torch.tensor(offsets[:-1]).cumsum(dim=0) #返回维度dim中输入元素的累计和
return text_list.to(device), label_list.to(device), offsets.to(device)
#数据加载器
dataloader = DataLoader(
train_iter,
batch_size = 8,
shuffle = False,
collate_fn = collate_batch
)
三、模型构建
1. 搭建模型
#搭建模型
from torch import nn
class TextClassificationModel(nn.Module):
def __init__(self, vocab_size, embed_dim, num_class):
super(TextClassificationModel,self).__init__()
self.embedding = nn.EmbeddingBag(vocab_size, #词典大小
embed_dim, # 嵌入的维度
sparse=False) #
self.fc = nn.Linear(embed_dim, num_class)
self.init_weights()
def init_weights(self):
initrange = 0.5
self.embedding.weight.data.uniform_(-initrange, initrange)
self.fc.weight.data.uniform_(-initrange, initrange)
self.fc.bias.data.zero_()
def forward(self, text, offsets):
embedded = self.embedding(text, offsets)
return self.fc(embedded)
2. 初始化模型
#初始化模型
#定义实例
num_class = len(label_name)
vocab_size = len(vocab)
em_size = 64
model = TextClassificationModel(vocab_size, em_size, num_class).to(device)
3. 定义训练与评估函数
#定义训练与评估函数
import time
def train(dataloader):
model.train() #切换为训练模式
total_acc, train_loss, total_count = 0,0,0
log_interval = 50
start_time = time.time()
for idx, (text,label, offsets) in enumerate(dataloader):
predicted_label = model(text, offsets)
optimizer.zero_grad() #grad属性归零
loss = criterion(predicted_label, label) #计算网络输出和真实值之间的差距,label为真
loss.backward() #反向传播
torch.nn.utils.clip_grad_norm_(model.parameters(),0.1) #梯度裁剪
optimizer.step() #每一步自动更新
#记录acc与loss
total_acc += (predicted_label.argmax(1) == label).sum().item()
train_loss += loss.item()
total_count += label.size(0)
if idx % log_interval == 0 and idx > 0:
elapsed = time.time() - start_time
print('|epoch{:d}|{:4d}/{:4d} batches|train_acc{:4.3f} train_loss{:4.5f}'.format(
epoch,
idx,
len(dataloader),
total_acc/total_count,
train_loss/total_count))
total_acc,train_loss,total_count = 0,0,0
staet_time = time.time()
def evaluate(dataloader):
model.eval() #切换为测试模式
total_acc,train_loss,total_count = 0,0,0
with torch.no_grad():
for idx,(text,label,offsets) in enumerate(dataloader):
predicted_label = model(text, offsets)
loss = criterion(predicted_label,label) #计算loss值
#记录测试数据
total_acc += (predicted_label.argmax(1) == label).sum().item()
train_loss += loss.item()
total_count += label.size(0)
return total_acc/total_count, train_loss/total_count
四、训练模型
1. 拆分数据集并运行模型
#拆分数据集并运行模型
from torch.utils.data.dataset import random_split
from torchtext.data.functional import to_map_style_dataset
# 超参数设定
EPOCHS = 10 #epoch
LR = 5 #learningRate
BATCH_SIZE = 64 #batch size for training
#设置损失函数、选择优化器、设置学习率调整函数
criterion = torch.nn.CrossEntropyLoss()
optimizer = torch.optim.SGD(model.parameters(), lr = LR)
scheduler = torch.optim.lr_scheduler.StepLR(optimizer, 1.0, gamma = 0.1)
total_accu = None
# 构建数据集
train_iter = custom_data_iter(train_data[0].values[:],train_data[1].values[:])
train_dataset = to_map_style_dataset(train_iter)
split_train_, split_valid_ = random_split(train_dataset,
[int(len(train_dataset)*0.8),int(len(train_dataset)*0.2)])
train_dataloader = DataLoader(split_train_, batch_size = BATCH_SIZE, shuffle = True, collate_fn = collate_batch)
valid_dataloader = DataLoader(split_valid_, batch_size = BATCH_SIZE, shuffle = True, collate_fn = collate_batch)
for epoch in range(1, EPOCHS + 1):
epoch_start_time = time.time()
train(train_dataloader)
val_acc, val_loss = evaluate(valid_dataloader)
#获取当前的学习率
lr = optimizer.state_dict()['param_groups'][0]['lr']
if total_accu is not None and total_accu > val_acc:
scheduler.step()
else:
total_accu = val_acc
print('-' * 69)
print('| epoch {:d} | time:{:4.2f}s | valid_acc {:4.3f} valid_loss {:4.3f}'.format(
epoch,
time.time() - epoch_start_time,
val_acc,
val_loss))
print('-' * 69)
输出:
['还有双鸭山到淮阴的汽车票吗13号的' '从这里怎么回家' '随便播放一首专辑阁楼里的佛里的歌' ...
'黎耀祥陈豪邓萃雯畲诗曼陈法拉敖嘉年杨怡马浚伟等到场出席' '百事盖世群星星光演唱会有谁' '下周一视频会议的闹钟帮我开开']
|epoch1| 50/ 152 batches|train_acc0.953 train_loss0.00282
|epoch1| 100/ 152 batches|train_acc0.953 train_loss0.00271
|epoch1| 150/ 152 batches|train_acc0.952 train_loss0.00292
---------------------------------------------------------------------
| epoch 1 | time:5.50s | valid_acc 0.949 valid_loss 0.003
---------------------------------------------------------------------
|epoch2| 50/ 152 batches|train_acc0.961 train_loss0.00231
|epoch2| 100/ 152 batches|train_acc0.967 train_loss0.00204
|epoch2| 150/ 152 batches|train_acc0.963 train_loss0.00228
---------------------------------------------------------------------
| epoch 2 | time:5.06s | valid_acc 0.949 valid_loss 0.003
---------------------------------------------------------------------
|epoch3| 50/ 152 batches|train_acc0.975 train_loss0.00173
|epoch3| 100/ 152 batches|train_acc0.973 train_loss0.00177
|epoch3| 150/ 152 batches|train_acc0.972 train_loss0.00166
---------------------------------------------------------------------
| epoch 3 | time:5.07s | valid_acc 0.948 valid_loss 0.003
---------------------------------------------------------------------
|epoch4| 50/ 152 batches|train_acc0.984 train_loss0.00137
|epoch4| 100/ 152 batches|train_acc0.987 train_loss0.00123
|epoch4| 150/ 152 batches|train_acc0.983 train_loss0.00119
---------------------------------------------------------------------
| epoch 4 | time:5.07s | valid_acc 0.950 valid_loss 0.003
---------------------------------------------------------------------
|epoch5| 50/ 152 batches|train_acc0.985 train_loss0.00125
|epoch5| 100/ 152 batches|train_acc0.987 train_loss0.00119
|epoch5| 150/ 152 batches|train_acc0.986 train_loss0.00120
---------------------------------------------------------------------
| epoch 5 | time:5.03s | valid_acc 0.949 valid_loss 0.003
---------------------------------------------------------------------
|epoch6| 50/ 152 batches|train_acc0.985 train_loss0.00118
|epoch6| 100/ 152 batches|train_acc0.989 train_loss0.00114
|epoch6| 150/ 152 batches|train_acc0.985 train_loss0.00120
---------------------------------------------------------------------
| epoch 6 | time:5.40s | valid_acc 0.949 valid_loss 0.003
---------------------------------------------------------------------
|epoch7| 50/ 152 batches|train_acc0.984 train_loss0.00119
|epoch7| 100/ 152 batches|train_acc0.986 train_loss0.00119
|epoch7| 150/ 152 batches|train_acc0.989 train_loss0.00112
---------------------------------------------------------------------
| epoch 7 | time:5.71s | valid_acc 0.949 valid_loss 0.003
---------------------------------------------------------------------
|epoch8| 50/ 152 batches|train_acc0.985 train_loss0.00115
|epoch8| 100/ 152 batches|train_acc0.986 train_loss0.00128
|epoch8| 150/ 152 batches|train_acc0.989 train_loss0.00107
---------------------------------------------------------------------
| epoch 8 | time:5.22s | valid_acc 0.949 valid_loss 0.003
---------------------------------------------------------------------
|epoch9| 50/ 152 batches|train_acc0.988 train_loss0.00114
|epoch9| 100/ 152 batches|train_acc0.983 train_loss0.00127
|epoch9| 150/ 152 batches|train_acc0.989 train_loss0.00109
---------------------------------------------------------------------
| epoch 9 | time:5.28s | valid_acc 0.949 valid_loss 0.003
---------------------------------------------------------------------
|epoch10| 50/ 152 batches|train_acc0.986 train_loss0.00115
|epoch10| 100/ 152 batches|train_acc0.987 train_loss0.00117
|epoch10| 150/ 152 batches|train_acc0.986 train_loss0.00119
---------------------------------------------------------------------
| epoch 10 | time:5.22s | valid_acc 0.949 valid_loss 0.003
---------------------------------------------------------------------
test_acc,test_loss = evaluate(valid_dataloader)
print('模型准确率为:{:5.4f}'.format(test_acc))
输出:
模型准确率为:0.9492
2. 测试指定数据
#测试指定的数据
def predict(text, text_pipeline):
with torch.no_grad():
text = torch.tensor(text_pipeline(text))
output = model(text, torch.tensor([0]))
return output.argmax(1).item()
ex_text_str = "还有双鸭山到淮阴的汽车票吗13号的"
model = model.to("cpu")
print("该文本的类别是: %s" %label_name[predict(ex_text_str,text_pipeline)])
输出:
该文本的类别是: Travel-Query
五、总结
训练神经网络时,可使用梯度裁剪的方法来防止梯度爆炸,使得模型训练更加稳定