⚠️ 此模型已弃用。请勿使用，因为它生成的句子嵌入质量较低。您可以在此处找到推荐的句子嵌入模型：SBERT.net - 预训练模型

sentence-transformers/distilbert-base-nli-mean-tokens

这是一个 sentence-transformers 模型：它将句子和段落映射到 768 维的稠密向量空间，可用于聚类或语义搜索等任务。

使用方法 (Sentence-Transformers)

安装 sentence-transformers 后，使用此模型变得非常简单：

pip install -U sentence-transformers

然后你可以这样使用模型：

from sentence_transformers import SentenceTransformer
sentences = ["This is an example sentence", "Each sentence is converted"]

model = SentenceTransformer('sentence-transformers/distilbert-base-nli-mean-tokens')
embeddings = model.encode(sentences)
print(embeddings)

使用方法 (HuggingFace Transformers)

如果没有 sentence-transformers，你可以这样使用模型：首先将输入通过变换器模型，然后必须在上下文词嵌入之上应用正确的池化操作。

from transformers import AutoTokenizer, AutoModel
import torch


#Mean Pooling - 注意考虑注意力掩码进行正确平均
def mean_pooling(model_output, attention_mask):
    token_embeddings = model_output[0] #model_output的第一个元素包含所有词嵌入
    input_mask_expanded = attention_mask.unsqueeze(-1).expand(token_embeddings.size()).float()
    return torch.sum(token_embeddings * input_mask_expanded, 1) / torch.clamp(input_mask_expanded.sum(1), min=1e-9)


# 我们想要获取句子嵌入的句子
sentences = ['This is an example sentence', 'Each sentence is converted']

# 从HuggingFace Hub加载模型
tokenizer = AutoTokenizer.from_pretrained('sentence-transformers/distilbert-base-nli-mean-tokens')
model = AutoModel.from_pretrained('sentence-transformers/distilbert-base-nli-mean-tokens')

# 对句子进行分词
encoded_input = tokenizer(sentences, padding=True, truncation=True, return_tensors='pt')

# 计算词嵌入
with torch.no_grad():
    model_output = model(**encoded_input)

# 执行池化。在这种情况下，是mean pooling。
sentence_embeddings = mean_pooling(model_output, encoded_input['attention_mask'])

print("句子嵌入：")
print(sentence_embeddings)

完整模型架构

SentenceTransformer(
  (0): Transformer({'max_seq_length': 128, 'do_lower_case': False}) with Transformer model: DistilBertModel 
  (1): Pooling({'word_embedding_dimension': 768, 'pooling_mode_cls_token': False, 'pooling_mode_mean_tokens': True, 'pooling_mode_max_tokens': False, 'pooling_mode_mean_sqrt_len_tokens': False})
)

引用 & 作者

此模型由 sentence-transformers 训练。

如果您觉得此模型有帮助，请引用我们的论文 Sentence-BERT: Sentence Embeddings using Siamese BERT-Networks：

@inproceedings{reimers-2019-sentence-bert,
    title = "Sentence-BERT: Sentence Embeddings using Siamese BERT-Networks",
    author = "Reimers, Nils and Gurevych, Iryna",
    booktitle = "Proceedings of the 2019 Conference on Empirical Methods in Natural Language Processing",
    month = "11",
    year = "2019",
    publisher = "Association for Computational Linguistics",
    url = "http://arxiv.org/abs/1908.10084",
}