HuggingFace镜像/msmarco-distilbert-base-tas-b
模型介绍文件和版本分析
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sentence-transformers/msmarco-distilbert-base-tas-b

这是 DistilBert TAS-B 模型 到 sentence-transformers 模型的移植版本:它能将句子和段落映射到 768 维的稠密向量空间,并针对语义搜索任务进行了优化。

用法(Sentence-Transformers)

当您安装了 sentence-transformers 后,使用此模型会变得非常简单:

pip install -U sentence-transformers

然后您可以像这样使用该模型:

from sentence_transformers import SentenceTransformer, util

query = "How many people live in London?"
docs = ["Around 9 Million people live in London", "London is known for its financial district"]

#Load the model
model = SentenceTransformer('sentence-transformers/msmarco-distilbert-base-tas-b')

#Encode query and documents
query_emb = model.encode(query)
doc_emb = model.encode(docs)

#Compute dot score between query and all document embeddings
scores = util.dot_score(query_emb, doc_emb)[0].cpu().tolist()

#Combine docs & scores
doc_score_pairs = list(zip(docs, scores))

#Sort by decreasing score
doc_score_pairs = sorted(doc_score_pairs, key=lambda x: x[1], reverse=True)

#Output passages & scores
for doc, score in doc_score_pairs:
    print(score, doc)

使用方法(HuggingFace Transformers)

如果不使用 sentence-transformers,您可以这样使用该模型:首先,将输入传递给 transformer 模型,然后必须在上下文单词嵌入之上应用正确的池化操作。

from openmind import AutoTokenizer, AutoModel, is_torch_npu_available
from openmind_hub import snapshot_download
import torch.nn.functional as F
import torch
import argparse

def parse_args():
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "--model_name_or_path",
        type=str,
        help="Path to model",
        default="zhouhui/msmarco-distilbert-base-tas-b",
    )
    args = parser.parse_args()
    return args

#CLS Pooling - Take output from first token
def cls_pooling(model_output):
    return model_output.last_hidden_state[:,0]

#Encode text
def encode(texts,tokenizer,model):
    # Tokenize sentences
    encoded_input = tokenizer(texts, padding=True, truncation=True, return_tensors='pt')

    # Compute token embeddings
    with torch.no_grad():
        model_output = model(**encoded_input, return_dict=True)

    # Perform pooling
    embeddings = cls_pooling(model_output)

    return embeddings

def main():
    args = parse_args()
    model_path = args.model_name_or_path

    if is_torch_npu_available():
        device = "npu:0"
    else:
        device = "cpu"
        
    # Sentences we want sentence embeddings for
    query = "How many people live in London?"
    docs = ["Around 9 Million people live in London", "London is known for its financial district"]

    tokenizer = AutoTokenizer.from_pretrained(model_path)
    model = AutoModel.from_pretrained(model_path)

    #Encode query and docs
    query_emb = encode(query,tokenizer,model)
    doc_emb = encode(docs,tokenizer,model)

    #Compute dot score between query and all document embeddings
    scores = torch.mm(query_emb, doc_emb.transpose(0, 1))[0].cpu().tolist()

    #Combine docs & scores
    doc_score_pairs = list(zip(docs, scores))

    #Sort by decreasing score
    doc_score_pairs = sorted(doc_score_pairs, key=lambda x: x[1], reverse=True)

    #Output passages & scores
    for doc, score in doc_score_pairs:
        print(score, doc)
    
if __name__ == "__main__":
    main()

评估结果

有关此模型的自动化评估,请参见“句子嵌入基准测试”:https://seb.sbert.net

完整模型架构

SentenceTransformer(
  (0): Transformer({'max_seq_length': 512, 'do_lower_case': False}) with Transformer model: DistilBertModel 
  (1): Pooling({'word_embedding_dimension': 768, 'pooling_mode_cls_token': True, 'pooling_mode_mean_tokens': False, 'pooling_mode_max_tokens': False, 'pooling_mode_mean_sqrt_len_tokens': False})
)

引用与作者

请查看:DistilBert TAS-B Model