from typing import Any, Dict, List, Optional
from langchain_core.embeddings import Embeddings
from langchain_core.pydantic_v1 import BaseModel
[docs]class QuantizedBiEncoderEmbeddings(BaseModel, Embeddings):
"""Quantized bi-encoders embedding models.
Please ensure that you have installed optimum-intel and ipex.
Input:
model_name: str = Model name.
max_seq_len: int = The maximum sequence length for tokenization. (default 512)
pooling_strategy: str =
"mean" or "cls", pooling strategy for the final layer. (default "mean")
query_instruction: Optional[str] =
An instruction to add to the query before embedding. (default None)
document_instruction: Optional[str] =
An instruction to add to each document before embedding. (default None)
padding: Optional[bool] =
Whether to add padding during tokenization or not. (default True)
model_kwargs: Optional[Dict] =
Parameters to add to the model during initialization. (default {})
encode_kwargs: Optional[Dict] =
Parameters to add during the embedding forward pass. (default {})
Example:
from langchain_community.embeddings import QuantizedBiEncoderEmbeddings
model_name = "Intel/bge-small-en-v1.5-rag-int8-static"
encode_kwargs = {'normalize_embeddings': True}
hf = QuantizedBiEncoderEmbeddings(
model_name,
encode_kwargs=encode_kwargs,
query_instruction="Represent this sentence for searching relevant passages: "
)
"""
def __init__(
self,
model_name: str,
max_seq_len: int = 512,
pooling_strategy: str = "mean", # "mean" or "cls"
query_instruction: Optional[str] = None,
document_instruction: Optional[str] = None,
padding: bool = True,
model_kwargs: Optional[Dict] = None,
encode_kwargs: Optional[Dict] = None,
**kwargs: Any,
) -> None:
super().__init__(**kwargs)
self.model_name_or_path = model_name
self.max_seq_len = max_seq_len
self.pooling = pooling_strategy
self.padding = padding
self.encode_kwargs = encode_kwargs or {}
self.model_kwargs = model_kwargs or {}
self.normalize = self.encode_kwargs.get("normalize_embeddings", False)
self.batch_size = self.encode_kwargs.get("batch_size", 32)
self.query_instruction = query_instruction
self.document_instruction = document_instruction
self.load_model()
[docs] def load_model(self) -> None:
try:
from transformers import AutoTokenizer
except ImportError as e:
raise ImportError(
"Unable to import transformers, please install with "
"`pip install -U transformers`."
) from e
try:
from optimum.intel import IPEXModel
self.transformer_model = IPEXModel.from_pretrained(
self.model_name_or_path, **self.model_kwargs
)
except Exception as e:
raise Exception(
f"""
Failed to load model {self.model_name_or_path}, due to the following error:
{e}
Please ensure that you have installed optimum-intel and ipex correctly,using:
pip install optimum[neural-compressor]
pip install intel_extension_for_pytorch
For more information, please visit:
* Install optimum-intel as shown here: https://github.com/huggingface/optimum-intel.
* Install IPEX as shown here: https://intel.github.io/intel-extension-for-pytorch/index.html#installation?platform=cpu&version=v2.2.0%2Bcpu.
"""
)
self.transformer_tokenizer = AutoTokenizer.from_pretrained(
pretrained_model_name_or_path=self.model_name_or_path,
)
self.transformer_model.eval()
class Config:
extra = "allow"
def _embed(self, inputs: Any) -> Any:
try:
import torch
except ImportError as e:
raise ImportError(
"Unable to import torch, please install with `pip install -U torch`."
) from e
with torch.inference_mode():
outputs = self.transformer_model(**inputs)
if self.pooling == "mean":
emb = self._mean_pooling(outputs, inputs["attention_mask"])
elif self.pooling == "cls":
emb = self._cls_pooling(outputs)
else:
raise ValueError("pooling method no supported")
if self.normalize:
emb = torch.nn.functional.normalize(emb, p=2, dim=1)
return emb
@staticmethod
def _cls_pooling(outputs: Any) -> Any:
if isinstance(outputs, dict):
token_embeddings = outputs["last_hidden_state"]
else:
token_embeddings = outputs[0]
return token_embeddings[:, 0]
@staticmethod
def _mean_pooling(outputs: Any, attention_mask: Any) -> Any:
try:
import torch
except ImportError as e:
raise ImportError(
"Unable to import torch, please install with `pip install -U torch`."
) from e
if isinstance(outputs, dict):
token_embeddings = outputs["last_hidden_state"]
else:
# First element of model_output contains all token embeddings
token_embeddings = outputs[0]
input_mask_expanded = (
attention_mask.unsqueeze(-1).expand(token_embeddings.size()).float()
)
sum_embeddings = torch.sum(token_embeddings * input_mask_expanded, 1)
sum_mask = torch.clamp(input_mask_expanded.sum(1), min=1e-9)
return sum_embeddings / sum_mask
def _embed_text(self, texts: List[str]) -> List[List[float]]:
inputs = self.transformer_tokenizer(
texts,
max_length=self.max_seq_len,
truncation=True,
padding=self.padding,
return_tensors="pt",
)
return self._embed(inputs).tolist()
[docs] def embed_documents(self, texts: List[str]) -> List[List[float]]:
"""Embed a list of text documents using the Optimized Embedder model.
Input:
texts: List[str] = List of text documents to embed.
Output:
List[List[float]] = The embeddings of each text document.
"""
try:
import pandas as pd
except ImportError as e:
raise ImportError(
"Unable to import pandas, please install with `pip install -U pandas`."
) from e
try:
from tqdm import tqdm
except ImportError as e:
raise ImportError(
"Unable to import tqdm, please install with `pip install -U tqdm`."
) from e
docs = [
self.document_instruction + d if self.document_instruction else d
for d in texts
]
# group into batches
text_list_df = pd.DataFrame(docs, columns=["texts"]).reset_index()
# assign each example with its batch
text_list_df["batch_index"] = text_list_df["index"] // self.batch_size
# create groups
batches = list(text_list_df.groupby(["batch_index"])["texts"].apply(list))
vectors = []
for batch in tqdm(batches, desc="Batches"):
vectors += self._embed_text(batch)
return vectors
[docs] def embed_query(self, text: str) -> List[float]:
if self.query_instruction:
text = self.query_instruction + text
return self._embed_text([text])[0]
