Source code for langchain_community.document_transformers.long_context_reorder
"""Reorder documents"""
from typing import Any, List, Sequence
from langchain_core.documents import BaseDocumentTransformer, Document
from langchain_core.pydantic_v1 import BaseModel
def _litm_reordering(documents: List[Document]) -> List[Document]:
"""Lost in the middle reorder: the less relevant documents will be at the
middle of the list and more relevant elements at beginning / end.
See: https://arxiv.org/abs//2307.03172"""
documents.reverse()
reordered_result = []
for i, value in enumerate(documents):
if i % 2 == 1:
reordered_result.append(value)
else:
reordered_result.insert(0, value)
return reordered_result
[docs]class LongContextReorder(BaseDocumentTransformer, BaseModel):
"""Reorder long context.
Lost in the middle:
Performance degrades when models must access relevant information
in the middle of long contexts.
See: https://arxiv.org/abs//2307.03172"""
class Config:
arbitrary_types_allowed = True
[docs] def transform_documents(
self, documents: Sequence[Document], **kwargs: Any
) -> Sequence[Document]:
"""Reorders documents."""
return _litm_reordering(list(documents))
[docs] async def atransform_documents(
self, documents: Sequence[Document], **kwargs: Any
) -> Sequence[Document]:
return _litm_reordering(list(documents))