mirror of
https://github.com/hwchase17/langchain
synced 2024-11-10 01:10:59 +00:00
209 lines
7.5 KiB
Python
209 lines
7.5 KiB
Python
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from typing import Any, Dict, List, Optional
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from langchain_core.embeddings import Embeddings
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from langchain_core.pydantic_v1 import BaseModel, Extra
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class QuantizedBiEncoderEmbeddings(BaseModel, Embeddings):
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"""Quantized bi-encoders embedding models.
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Please ensure that you have installed optimum-intel and ipex.
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Input:
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model_name: str = Model name.
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max_seq_len: int = The maximum sequence length for tokenization. (default 512)
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pooling_strategy: str =
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"mean" or "cls", pooling strategy for the final layer. (default "mean")
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query_instruction: Optional[str] =
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An instruction to add to the query before embedding. (default None)
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document_instruction: Optional[str] =
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An instruction to add to each document before embedding. (default None)
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padding: Optional[bool] =
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Whether to add padding during tokenization or not. (default True)
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model_kwargs: Optional[Dict] =
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Parameters to add to the model during initialization. (default {})
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encode_kwargs: Optional[Dict] =
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Parameters to add during the embedding forward pass. (default {})
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Example:
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from langchain_community.embeddings import QuantizedBiEncoderEmbeddings
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model_name = "Intel/bge-small-en-v1.5-rag-int8-static"
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encode_kwargs = {'normalize_embeddings': True}
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hf = QuantizedBiEncoderEmbeddings(
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model_name,
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encode_kwargs=encode_kwargs,
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query_instruction="Represent this sentence for searching relevant passages: "
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)
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"""
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def __init__(
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self,
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model_name: str,
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max_seq_len: int = 512,
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pooling_strategy: str = "mean", # "mean" or "cls"
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query_instruction: Optional[str] = None,
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document_instruction: Optional[str] = None,
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padding: bool = True,
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model_kwargs: Optional[Dict] = None,
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encode_kwargs: Optional[Dict] = None,
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**kwargs: Any,
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) -> None:
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super().__init__(**kwargs)
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self.model_name_or_path = model_name
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self.max_seq_len = max_seq_len
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self.pooling = pooling_strategy
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self.padding = padding
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self.encode_kwargs = encode_kwargs or {}
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self.model_kwargs = model_kwargs or {}
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self.normalize = self.encode_kwargs.get("normalize_embeddings", False)
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self.batch_size = self.encode_kwargs.get("batch_size", 32)
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self.query_instruction = query_instruction
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self.document_instruction = document_instruction
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self.load_model()
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def load_model(self) -> None:
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try:
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from transformers import AutoTokenizer
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except ImportError as e:
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raise ImportError(
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"Unable to import transformers, please install with "
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"`pip install -U transformers`."
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) from e
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try:
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from optimum.intel import IPEXModel
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self.transformer_model = IPEXModel.from_pretrained(
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self.model_name_or_path, **self.model_kwargs
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)
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except Exception as e:
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raise Exception(
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f"""
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Failed to load model {self.model_name_or_path}, due to the following error:
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{e}
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Please ensure that you have installed optimum-intel and ipex correctly,using:
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pip install optimum[neural-compressor]
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pip install intel_extension_for_pytorch
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For more information, please visit:
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* Install optimum-intel as shown here: https://github.com/huggingface/optimum-intel.
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* Install IPEX as shown here: https://intel.github.io/intel-extension-for-pytorch/index.html#installation?platform=cpu&version=v2.2.0%2Bcpu.
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"""
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)
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self.transformer_tokenizer = AutoTokenizer.from_pretrained(
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pretrained_model_name_or_path=self.model_name_or_path,
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)
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self.transformer_model.eval()
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class Config:
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"""Configuration for this pydantic object."""
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extra = Extra.allow
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def _embed(self, inputs: Any) -> Any:
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try:
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import torch
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except ImportError as e:
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raise ImportError(
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"Unable to import torch, please install with `pip install -U torch`."
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) from e
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with torch.inference_mode():
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outputs = self.transformer_model(**inputs)
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if self.pooling == "mean":
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emb = self._mean_pooling(outputs, inputs["attention_mask"])
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elif self.pooling == "cls":
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emb = self._cls_pooling(outputs)
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else:
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raise ValueError("pooling method no supported")
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if self.normalize:
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emb = torch.nn.functional.normalize(emb, p=2, dim=1)
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return emb
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@staticmethod
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def _cls_pooling(outputs: Any) -> Any:
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if isinstance(outputs, dict):
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token_embeddings = outputs["last_hidden_state"]
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else:
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token_embeddings = outputs[0]
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return token_embeddings[:, 0]
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@staticmethod
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def _mean_pooling(outputs: Any, attention_mask: Any) -> Any:
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try:
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import torch
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except ImportError as e:
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raise ImportError(
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"Unable to import torch, please install with `pip install -U torch`."
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) from e
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if isinstance(outputs, dict):
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token_embeddings = outputs["last_hidden_state"]
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else:
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# First element of model_output contains all token embeddings
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token_embeddings = outputs[0]
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input_mask_expanded = (
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attention_mask.unsqueeze(-1).expand(token_embeddings.size()).float()
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)
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sum_embeddings = torch.sum(token_embeddings * input_mask_expanded, 1)
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sum_mask = torch.clamp(input_mask_expanded.sum(1), min=1e-9)
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return sum_embeddings / sum_mask
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def _embed_text(self, texts: List[str]) -> List[List[float]]:
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inputs = self.transformer_tokenizer(
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texts,
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max_length=self.max_seq_len,
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truncation=True,
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padding=self.padding,
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return_tensors="pt",
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)
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return self._embed(inputs).tolist()
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def embed_documents(self, texts: List[str]) -> List[List[float]]:
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"""Embed a list of text documents using the Optimized Embedder model.
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Input:
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texts: List[str] = List of text documents to embed.
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Output:
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List[List[float]] = The embeddings of each text document.
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"""
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try:
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import pandas as pd
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except ImportError as e:
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raise ImportError(
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"Unable to import pandas, please install with `pip install -U pandas`."
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) from e
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try:
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import tqdm
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except ImportError as e:
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raise ImportError(
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"Unable to import tqdm, please install with `pip install -U tqdm`."
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) from e
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docs = [
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self.document_instruction + d if self.document_instruction else d
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for d in texts
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]
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# group into batches
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text_list_df = pd.DataFrame(docs, columns=["texts"]).reset_index()
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# assign each example with its batch
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text_list_df["batch_index"] = text_list_df["index"] // self.batch_size
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# create groups
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batches = list(text_list_df.groupby(["batch_index"])["texts"].apply(list))
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vectors = []
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for batch in tqdm(batches, desc="Batches"):
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vectors += self._embed_text(batch)
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return vectors
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def embed_query(self, text: str) -> List[float]:
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if self.query_instruction:
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text = self.query_instruction + text
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return self._embed_text([text])[0]
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