近因过滤¶

展示近因加权节点后处理器的功能

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import os

os.environ["OPENAI_API_KEY"] = "sk-..."

import os os.environ["OPENAI_API_KEY"] = "sk-..."

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from llama_index.core import VectorStoreIndex, SimpleDirectoryReader
from llama_index.core.postprocessor import (
    FixedRecencyPostprocessor,
    EmbeddingRecencyPostprocessor,
)
from llama_index.core.node_parser import SentenceSplitter
from llama_index.core.storage.docstore import SimpleDocumentStore
from llama_index.core.response.notebook_utils import display_response

from llama_index.core import VectorStoreIndex, SimpleDirectoryReader from llama_index.core.postprocessor import ( FixedRecencyPostprocessor, EmbeddingRecencyPostprocessor, ) from llama_index.core.node_parser import SentenceSplitter from llama_index.core.storage.docstore import SimpleDocumentStore from llama_index.core.response.notebook_utils import display_response

将文档解析为节点，添加到 Docstore¶

在本例中，PG 的论文有 3 个不同版本。它们大体相同，除了一个具体的部分，该部分详细说明了他们为 Viaweb 筹集的资金金额。

V1: 5 万, V2: 3 万, V3: 1 万

V1: 2020-01-01, V2: 2020-02-03, V3: 2022-04-12

目的是鼓励索引获取最新信息（即 V3）

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# load documents
from llama_index.core import StorageContext


def get_file_metadata(file_name: str):
    """Get file metadata."""
    if "v1" in file_name:
        return {"date": "2020-01-01"}
    elif "v2" in file_name:
        return {"date": "2020-02-03"}
    elif "v3" in file_name:
        return {"date": "2022-04-12"}
    else:
        raise ValueError("invalid file")


documents = SimpleDirectoryReader(
    input_files=[
        "test_versioned_data/paul_graham_essay_v1.txt",
        "test_versioned_data/paul_graham_essay_v2.txt",
        "test_versioned_data/paul_graham_essay_v3.txt",
    ],
    file_metadata=get_file_metadata,
).load_data()

# define settings
from llama_index.core import Settings

Settings.text_splitter = SentenceSplitter(chunk_size=512)

# use node parser to parse into nodes
nodes = Settings.text_splitter.get_nodes_from_documents(documents)

# add to docstore
docstore = SimpleDocumentStore()
docstore.add_documents(nodes)

storage_context = StorageContext.from_defaults(docstore=docstore)

# load documents from llama_index.core import StorageContext def get_file_metadata(file_name: str): """Get file metadata.""" if "v1" in file_name: return {"date": "2020-01-01"} elif "v2" in file_name: return {"date": "2020-02-03"} elif "v3" in file_name: return {"date": "2022-04-12"} else: raise ValueError("invalid file") documents = SimpleDirectoryReader( input_files=[ "test_versioned_data/paul_graham_essay_v1.txt", "test_versioned_data/paul_graham_essay_v2.txt", "test_versioned_data/paul_graham_essay_v3.txt", ], file_metadata=get_file_metadata, ).load_data() # define settings from llama_index.core import Settings Settings.text_splitter = SentenceSplitter(chunk_size=512) # use node parser to parse into nodes nodes = Settings.text_splitter.get_nodes_from_documents(documents) # add to docstore docstore = SimpleDocumentStore() docstore.add_documents(nodes) storage_context = StorageContext.from_defaults(docstore=docstore)

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print(documents[2].get_text())

print(documents[2].get_text())

构建索引¶

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# build index
index = VectorStoreIndex(nodes, storage_context=storage_context)

# build index index = VectorStoreIndex(nodes, storage_context=storage_context)

INFO:llama_index.token_counter.token_counter:> [build_index_from_nodes] Total LLM token usage: 0 tokens
INFO:llama_index.token_counter.token_counter:> [build_index_from_nodes] Total embedding token usage: 84471 tokens

定义近因后处理器¶

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node_postprocessor = FixedRecencyPostprocessor()

node_postprocessor = FixedRecencyPostprocessor()

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node_postprocessor_emb = EmbeddingRecencyPostprocessor()

node_postprocessor_emb = EmbeddingRecencyPostprocessor()

查询索引¶

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# naive query

query_engine = index.as_query_engine(
    similarity_top_k=3,
)
response = query_engine.query(
    "How much did the author raise in seed funding from Idelle's husband"
    " (Julian) for Viaweb?",
)

# naive query query_engine = index.as_query_engine( similarity_top_k=3, ) response = query_engine.query( "How much did the author raise in seed funding from Idelle's husband" " (Julian) for Viaweb?", )

INFO:llama_index.token_counter.token_counter:> [query] Total LLM token usage: 1813 tokens
INFO:llama_index.token_counter.token_counter:> [query] Total embedding token usage: 22 tokens

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# query using fixed recency node postprocessor

query_engine = index.as_query_engine(
    similarity_top_k=3, node_postprocessors=[node_postprocessor]
)
response = query_engine.query(
    "How much did the author raise in seed funding from Idelle's husband"
    " (Julian) for Viaweb?",
)

# query using fixed recency node postprocessor query_engine = index.as_query_engine( similarity_top_k=3, node_postprocessors=[node_postprocessor] ) response = query_engine.query( "How much did the author raise in seed funding from Idelle's husband" " (Julian) for Viaweb?", )

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# query using embedding-based node postprocessor

query_engine = index.as_query_engine(
    similarity_top_k=3, node_postprocessors=[node_postprocessor_emb]
)
response = query_engine.query(
    "How much did the author raise in seed funding from Idelle's husband"
    " (Julian) for Viaweb?",
)

# query using embedding-based node postprocessor query_engine = index.as_query_engine( similarity_top_k=3, node_postprocessors=[node_postprocessor_emb] ) response = query_engine.query( "How much did the author raise in seed funding from Idelle's husband" " (Julian) for Viaweb?", )

INFO:llama_index.token_counter.token_counter:> [query] Total LLM token usage: 541 tokens
INFO:llama_index.token_counter.token_counter:> [query] Total embedding token usage: 22 tokens

查询索引（底层用法）¶

在本例中，我们首先从查询调用中获取完整的节点集，然后发送给节点后处理器，最后通过摘要索引合成响应。

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from llama_index.core import SummaryIndex

from llama_index.core import SummaryIndex

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query_str = (
    "How much did the author raise in seed funding from Idelle's husband"
    " (Julian) for Viaweb?"
)

query_str = ( "How much did the author raise in seed funding from Idelle's husband" " (Julian) for Viaweb?" )

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query_engine = index.as_query_engine(
    similarity_top_k=3, response_mode="no_text"
)
init_response = query_engine.query(
    query_str,
)
resp_nodes = [n.node for n in init_response.source_nodes]

query_engine = index.as_query_engine( similarity_top_k=3, response_mode="no_text" ) init_response = query_engine.query( query_str, ) resp_nodes = [n.node for n in init_response.source_nodes]

INFO:llama_index.token_counter.token_counter:> [query] Total LLM token usage: 0 tokens
INFO:llama_index.token_counter.token_counter:> [query] Total embedding token usage: 22 tokens

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summary_index = SummaryIndex(resp_nodes)
query_engine = summary_index.as_query_engine(
    node_postprocessors=[node_postprocessor]
)
response = query_engine.query(query_str)

summary_index = SummaryIndex(resp_nodes) query_engine = summary_index.as_query_engine( node_postprocessors=[node_postprocessor] ) response = query_engine.query(query_str)

INFO:llama_index.token_counter.token_counter:> [build_index_from_nodes] Total LLM token usage: 0 tokens
INFO:llama_index.token_counter.token_counter:> [build_index_from_nodes] Total embedding token usage: 0 tokens
INFO:llama_index.token_counter.token_counter:> [query] Total LLM token usage: 541 tokens
INFO:llama_index.token_counter.token_counter:> [query] Total embedding token usage: 0 tokens