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140 lines
4.4 KiB
Python
140 lines
4.4 KiB
Python
"""Wrapper around HuggingFace embedding models."""
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from typing import Any, List
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from pydantic import BaseModel, Extra
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from langchain.embeddings.base import Embeddings
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DEFAULT_MODEL_NAME = "sentence-transformers/all-mpnet-base-v2"
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DEFAULT_INSTRUCT_MODEL = "hkunlp/instructor-large"
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DEFAULT_EMBED_INSTRUCTION = "Represent the document for retrieval: "
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DEFAULT_QUERY_INSTRUCTION = (
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"Represent the question for retrieving supporting documents: "
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)
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class HuggingFaceEmbeddings(BaseModel, Embeddings):
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"""Wrapper around sentence_transformers embedding models.
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To use, you should have the ``sentence_transformers`` python package installed.
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Example:
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.. code-block:: python
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from langchain.embeddings import HuggingFaceEmbeddings
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model_name = "sentence-transformers/all-mpnet-base-v2"
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hf = HuggingFaceEmbeddings(model_name=model_name)
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"""
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client: Any #: :meta private:
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model_name: str = DEFAULT_MODEL_NAME
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"""Model name to use."""
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def __init__(self, **kwargs: Any):
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"""Initialize the sentence_transformer."""
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super().__init__(**kwargs)
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try:
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import sentence_transformers
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self.client = sentence_transformers.SentenceTransformer(self.model_name)
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except ImportError:
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raise ValueError(
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"Could not import sentence_transformers python package. "
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"Please install it with `pip install sentence_transformers`."
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)
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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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def embed_documents(self, texts: List[str]) -> List[List[float]]:
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"""Compute doc embeddings using a HuggingFace transformer model.
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Args:
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texts: The list of texts to embed.
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Returns:
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List of embeddings, one for each text.
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"""
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texts = list(map(lambda x: x.replace("\n", " "), texts))
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embeddings = self.client.encode(texts)
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return embeddings.tolist()
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def embed_query(self, text: str) -> List[float]:
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"""Compute query embeddings using a HuggingFace transformer model.
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Args:
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text: The text to embed.
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Returns:
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Embeddings for the text.
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"""
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text = text.replace("\n", " ")
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embedding = self.client.encode(text)
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return embedding.tolist()
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class HuggingFaceInstructEmbeddings(BaseModel, Embeddings):
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"""Wrapper around sentence_transformers embedding models.
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To use, you should have the ``sentence_transformers``
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and ``InstructorEmbedding`` python package installed.
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Example:
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.. code-block:: python
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from langchain.embeddings import HuggingFaceInstructEmbeddings
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model_name = "hkunlp/instructor-large"
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hf = HuggingFaceInstructEmbeddings(model_name=model_name)
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"""
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client: Any #: :meta private:
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model_name: str = DEFAULT_INSTRUCT_MODEL
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"""Model name to use."""
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embed_instruction: str = DEFAULT_EMBED_INSTRUCTION
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"""Instruction to use for embedding documents."""
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query_instruction: str = DEFAULT_QUERY_INSTRUCTION
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"""Instruction to use for embedding query."""
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def __init__(self, **kwargs: Any):
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"""Initialize the sentence_transformer."""
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super().__init__(**kwargs)
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try:
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from InstructorEmbedding import INSTRUCTOR
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self.client = INSTRUCTOR(self.model_name)
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except ImportError as e:
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raise ValueError("Dependencies for InstructorEmbedding not found.") from e
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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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def embed_documents(self, texts: List[str]) -> List[List[float]]:
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"""Compute doc embeddings using a HuggingFace instruct model.
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Args:
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texts: The list of texts to embed.
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Returns:
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List of embeddings, one for each text.
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"""
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instruction_pairs = [[self.embed_instruction, text] for text in texts]
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embeddings = self.client.encode(instruction_pairs)
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return embeddings.tolist()
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def embed_query(self, text: str) -> List[float]:
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"""Compute query embeddings using a HuggingFace instruct model.
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Args:
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text: The text to embed.
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Returns:
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Embeddings for the text.
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"""
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instruction_pair = [self.query_instruction, text]
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embedding = self.client.encode([instruction_pair])[0]
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return embedding.tolist()
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