TextRCNN-THUCNews/Classification/scripts/model.py

# coding: UTF-8
import torch
import torch.nn as nn
import torch.nn.functional as F
import numpy as np


class Config(object):

    """配置参数"""
    def __init__(self, dataset, embedding):
        self.model_name = 'TextRCNN'
        self.train_path = dataset + '/data/train.txt'                                # 训练集
        self.dev_path = dataset + '/data/dev.txt'                                    # 验证集
        self.test_path = dataset + '/data/test.txt'                                  # 测试集
        self.class_list = [x.strip() for x in open(
            dataset + '/data/class.txt', encoding='utf-8').readlines()]              # 类别名单
        self.vocab_path = dataset + '/data/vocab.pkl'                                # 词表
        self.save_path = dataset + '/saved_dict/' + self.model_name + '.ckpt'        # 模型训练结果
        self.log_path = dataset + '/log/' + self.model_name
        self.embedding_pretrained = torch.tensor(
            np.load(dataset + '/data/' + embedding)["embeddings"].astype('float32'))\
            if embedding != 'random' else None                                       # 预训练词向量
        self.device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')   # 设备

        self.dropout = 0.5                                              # 随机失活
        self.require_improvement = 1000                                 # 若超过1000batch效果还没提升，则提前结束训练
        self.num_classes = len(self.class_list)                         # 类别数
        self.n_vocab = 0                                                # 词表大小，在运行时赋值
        self.num_epochs = 10                                            # epoch数
        self.batch_size = 128                                           # mini-batch大小
        self.pad_size = 32                                              # 每句话处理成的长度(短填长切)
        self.learning_rate = 1e-3                                       # 学习率
        self.embed = self.embedding_pretrained.size(1)\
            if self.embedding_pretrained is not None else 300           # 字向量维度, 若使用了预训练词向量，则维度统一
        self.hidden_size = 256                                          # lstm隐藏层
        self.num_layers = 1                                             # lstm层数


'''Recurrent Convolutional Neural Networks for Text Classification'''


class TextRCNN(nn.Module):
    def __init__(self, config):
        super(TextRCNN, self).__init__()
        if config.embedding_pretrained is not None:
            self.embedding = nn.Embedding.from_pretrained(config.embedding_pretrained, freeze=False)
        else:
            self.embedding = nn.Embedding(config.n_vocab, config.embed, padding_idx=config.n_vocab - 1)
        self.lstm = nn.LSTM(config.embed, config.hidden_size, config.num_layers,
                            bidirectional=True, batch_first=True, 
                            dropout=config.dropout if config.num_layers > 1 else 0)
        self.maxpool = nn.MaxPool1d(config.pad_size)
        self.fc = nn.Linear(config.hidden_size * 2 + config.embed, config.num_classes)

    def forward(self, x):
        x, _ = x
        embed = self.embedding(x)  # [batch_size, seq_len, embeding]=[64, 32, 64]
        out, _ = self.lstm(embed)
        out = torch.cat((embed, out), 2)
        out = F.relu(out)
        out = out.permute(0, 2, 1)
        out = self.maxpool(out).squeeze()
        out = self.fc(out)
        return out
    
    def feature(self, x):
        """
        提取中间层特征向量，用于可视化
        返回maxpool层的输出（全连接层前面的那一层）
        """
        with torch.no_grad():
            x, _ = x
            embed = self.embedding(x)  # [batch_size, seq_len, embeding]
            out, _ = self.lstm(embed)  # [batch_size, seq_len, hidden_size * 2]
            out = torch.cat((embed, out), 2)  # [batch_size, seq_len, hidden_size * 2 + embed]
            out = F.relu(out)
            out = out.permute(0, 2, 1)  # [batch_size, hidden_size * 2 + embed, seq_len]
            features = self.maxpool(out).squeeze()  # [batch_size, hidden_size * 2 + embed]
            return features.cpu().numpy()
    
    def get_prediction(self, x):
        """
        获取模型最终层输出向量（logits）
        """
        with torch.no_grad():
            x, _ = x
            embed = self.embedding(x)
            out, _ = self.lstm(embed)
            out = torch.cat((embed, out), 2)
            out = F.relu(out)
            out = out.permute(0, 2, 1)
            out = self.maxpool(out).squeeze()
            predictions = self.fc(out)  # [batch_size, num_classes]
            return predictions.cpu().numpy()
    
    def prediction(self, features):
        """
        根据中间特征向量预测结果
        features: 来自feature()函数的输出 [batch_size, hidden_size * 2 + embed]
        """
        with torch.no_grad():
            features_tensor = torch.tensor(features, dtype=torch.float32).to(next(self.parameters()).device)
            predictions = self.fc(features_tensor)  # 直接通过最后的分类层
            return predictions.cpu().numpy()