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https://github.com/hwchase17/langchain
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e7e41eaabe
Integrate RankLLM reranker (https://github.com/castorini/rank_llm) into LangChain An example notebook is given in `docs/docs/integrations/retrievers/rankllm-reranker.ipynb` --------- Co-authored-by: Harrison Chase <hw.chase.17@gmail.com>
125 lines
4.1 KiB
Python
125 lines
4.1 KiB
Python
from __future__ import annotations
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from copy import deepcopy
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from enum import Enum
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from typing import TYPE_CHECKING, Any, Dict, Optional, Sequence
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from langchain.retrievers.document_compressors.base import BaseDocumentCompressor
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from langchain_core.callbacks.manager import Callbacks
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from langchain_core.documents import Document
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from langchain_core.pydantic_v1 import Extra, Field, PrivateAttr, root_validator
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from langchain_core.utils import get_from_dict_or_env
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if TYPE_CHECKING:
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from rank_llm.data import Candidate, Query, Request
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else:
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# Avoid pydantic annotation issues when actually instantiating
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# while keeping this import optional
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try:
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from rank_llm.data import Candidate, Query, Request
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except ImportError:
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pass
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class RankLLMRerank(BaseDocumentCompressor):
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"""Document compressor using Flashrank interface."""
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client: Any = None
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"""RankLLM client to use for compressing documents"""
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top_n: int = Field(default=3)
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"""Top N documents to return."""
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model: str = Field(default="zephyr")
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"""Name of model to use for reranking."""
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step_size: int = Field(default=10)
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"""Step size for moving sliding window."""
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gpt_model: str = Field(default="gpt-3.5-turbo")
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"""OpenAI model name."""
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_retriever: Any = PrivateAttr()
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class Config:
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"""Configuration for this pydantic object."""
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extra = Extra.forbid
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arbitrary_types_allowed = True
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@root_validator(pre=True)
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def validate_environment(cls, values: Dict) -> Dict:
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"""Validate python package exists in environment."""
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if not values.get("client"):
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client_name = values.get("model", "zephyr")
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try:
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model_enum = ModelType(client_name.lower())
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except ValueError:
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raise ValueError(
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"Unsupported model type. Please use 'vicuna', 'zephyr', or 'gpt'."
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)
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try:
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if model_enum == ModelType.VICUNA:
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from rank_llm.rerank.vicuna_reranker import VicunaReranker
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values["client"] = VicunaReranker()
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elif model_enum == ModelType.ZEPHYR:
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from rank_llm.rerank.zephyr_reranker import ZephyrReranker
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values["client"] = ZephyrReranker()
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elif model_enum == ModelType.GPT:
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from rank_llm.rerank.rank_gpt import SafeOpenai
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from rank_llm.rerank.reranker import Reranker
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openai_api_key = get_from_dict_or_env(
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values, "open_api_key", "OPENAI_API_KEY"
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)
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agent = SafeOpenai(
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model=values["gpt_model"],
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context_size=4096,
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keys=openai_api_key,
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)
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values["client"] = Reranker(agent)
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except ImportError:
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raise ImportError(
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"Could not import rank_llm python package. "
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"Please install it with `pip install rank_llm`."
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)
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return values
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def compress_documents(
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self,
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documents: Sequence[Document],
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query: str,
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callbacks: Optional[Callbacks] = None,
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) -> Sequence[Document]:
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request = Request(
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query=Query(text=query, qid=1),
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candidates=[
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Candidate(doc={"text": doc.page_content}, docid=index, score=1)
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for index, doc in enumerate(documents)
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],
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)
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rerank_results = self.client.rerank(
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request,
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rank_end=len(documents),
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window_size=min(20, len(documents)),
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step=10,
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)
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final_results = []
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for res in rerank_results.candidates:
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doc = documents[int(res.docid)]
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doc_copy = Document(doc.page_content, metadata=deepcopy(doc.metadata))
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final_results.append(doc_copy)
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return final_results[: self.top_n]
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class ModelType(Enum):
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VICUNA = "vicuna"
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ZEPHYR = "zephyr"
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GPT = "gpt"
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