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+"""Wrapper around weaviate vector database."""
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+from __future__ import annotations
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+
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+import datetime
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+from typing import Any, Callable, Dict, Iterable, List, Optional, Tuple, Type
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+from uuid import uuid4
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+
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+import numpy as np
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+
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+from langchain.docstore.document import Document
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+from langchain.embeddings.base import Embeddings
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+from langchain.utils import get_from_dict_or_env
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+from langchain.vectorstores.base import VectorStore
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+from langchain.vectorstores.utils import maximal_marginal_relevance
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+
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+
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+def _default_schema(index_name: str) -> Dict:
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+ return {
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+ "class": index_name,
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+ "properties": [
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+ {
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+ "name": "text",
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+ "dataType": ["text"],
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+ }
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+ ],
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+ }
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+
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+
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+def _create_weaviate_client(**kwargs: Any) -> Any:
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+ client = kwargs.get("client")
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+ if client is not None:
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+ return client
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+
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+ weaviate_url = get_from_dict_or_env(kwargs, "weaviate_url", "WEAVIATE_URL")
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+
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+ try:
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+
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+ weaviate_api_key = get_from_dict_or_env(
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+ kwargs, "weaviate_api_key", "WEAVIATE_API_KEY", None
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+ )
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+ except ValueError:
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+ weaviate_api_key = None
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+
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+ try:
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+ import weaviate
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+ except ImportError:
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+ raise ValueError(
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+ "Could not import weaviate python package. "
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+ "Please install it with `pip install weaviate-client`"
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+ )
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+
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+ auth = (
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+ weaviate.auth.AuthApiKey(api_key=weaviate_api_key)
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+ if weaviate_api_key is not None
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+ else None
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+ )
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+ client = weaviate.Client(weaviate_url, auth_client_secret=auth)
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+
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+ return client
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+
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+
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+def _default_score_normalizer(val: float) -> float:
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+ return 1 - 1 / (1 + np.exp(val))
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+
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+
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+def _json_serializable(value: Any) -> Any:
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+ if isinstance(value, datetime.datetime):
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+ return value.isoformat()
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+ return value
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+
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+
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+class Weaviate(VectorStore):
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+ """Wrapper around Weaviate vector database.
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+
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+ To use, you should have the ``weaviate-client`` python package installed.
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+
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+ Example:
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+ .. code-block:: python
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+
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+ import weaviate
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+ from langchain.vectorstores import Weaviate
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+ client = weaviate.Client(url=os.environ["WEAVIATE_URL"], ...)
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+ weaviate = Weaviate(client, index_name, text_key)
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+
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+ """
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+
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+ def __init__(
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+ self,
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+ client: Any,
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+ index_name: str,
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+ text_key: str,
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+ embedding: Optional[Embeddings] = None,
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+ attributes: Optional[List[str]] = None,
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+ relevance_score_fn: Optional[
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+ Callable[[float], float]
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+ ] = _default_score_normalizer,
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+ by_text: bool = True,
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+ ):
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+ """Initialize with Weaviate client."""
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+ try:
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+ import weaviate
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+ except ImportError:
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+ raise ValueError(
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+ "Could not import weaviate python package. "
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+ "Please install it with `pip install weaviate-client`."
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+ )
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+ if not isinstance(client, weaviate.Client):
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+ raise ValueError(
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+ f"client should be an instance of weaviate.Client, got {type(client)}"
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+ )
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+ self._client = client
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+ self._index_name = index_name
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+ self._embedding = embedding
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+ self._text_key = text_key
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+ self._query_attrs = [self._text_key]
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+ self.relevance_score_fn = relevance_score_fn
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+ self._by_text = by_text
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+ if attributes is not None:
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+ self._query_attrs.extend(attributes)
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+
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+ @property
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+ def embeddings(self) -> Optional[Embeddings]:
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+ return self._embedding
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+
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+ def _select_relevance_score_fn(self) -> Callable[[float], float]:
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+ return (
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+ self.relevance_score_fn
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+ if self.relevance_score_fn
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+ else _default_score_normalizer
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+ )
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+
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+ def add_texts(
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+ self,
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+ texts: Iterable[str],
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+ metadatas: Optional[List[dict]] = None,
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+ **kwargs: Any,
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+ ) -> List[str]:
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+ """Upload texts with metadata (properties) to Weaviate."""
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+ from weaviate.util import get_valid_uuid
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+
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+ ids = []
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+ embeddings: Optional[List[List[float]]] = None
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+ if self._embedding:
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+ if not isinstance(texts, list):
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+ texts = list(texts)
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+ embeddings = self._embedding.embed_documents(texts)
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+
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+ with self._client.batch as batch:
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+ for i, text in enumerate(texts):
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+ data_properties = {self._text_key: text}
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+ if metadatas is not None:
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+ for key, val in metadatas[i].items():
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+ data_properties[key] = _json_serializable(val)
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+
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+
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+
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+
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+
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+ _id = get_valid_uuid(uuid4())
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+ if "uuids" in kwargs:
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+ _id = kwargs["uuids"][i]
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+ elif "ids" in kwargs:
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+ _id = kwargs["ids"][i]
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+
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+ batch.add_data_object(
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+ data_object=data_properties,
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+ class_name=self._index_name,
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+ uuid=_id,
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+ vector=embeddings[i] if embeddings else None,
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+ )
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+ ids.append(_id)
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+ return ids
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+
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+ def similarity_search(
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+ self, query: str, k: int = 4, **kwargs: Any
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+ ) -> List[Document]:
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+ """Return docs most similar to query.
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+
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+ Args:
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+ query: Text to look up documents similar to.
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+ k: Number of Documents to return. Defaults to 4.
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+
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+ Returns:
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+ List of Documents most similar to the query.
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+ """
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+ if self._by_text:
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+ return self.similarity_search_by_text(query, k, **kwargs)
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+ else:
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+ if self._embedding is None:
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+ raise ValueError(
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+ "_embedding cannot be None for similarity_search when "
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+ "_by_text=False"
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+ )
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+ embedding = self._embedding.embed_query(query)
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+ return self.similarity_search_by_vector(embedding, k, **kwargs)
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+
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+ def similarity_search_by_text(
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+ self, query: str, k: int = 4, **kwargs: Any
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+ ) -> List[Document]:
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+ """Return docs most similar to query.
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+
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+ Args:
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+ query: Text to look up documents similar to.
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+ k: Number of Documents to return. Defaults to 4.
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+
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+ Returns:
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+ List of Documents most similar to the query.
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+ """
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+ content: Dict[str, Any] = {"concepts": [query]}
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+ if kwargs.get("search_distance"):
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+ content["certainty"] = kwargs.get("search_distance")
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+ query_obj = self._client.query.get(self._index_name, self._query_attrs)
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+ if kwargs.get("where_filter"):
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+ query_obj = query_obj.with_where(kwargs.get("where_filter"))
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+ if kwargs.get("additional"):
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+ query_obj = query_obj.with_additional(kwargs.get("additional"))
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+ result = query_obj.with_near_text(content).with_limit(k).do()
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+ if "errors" in result:
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+ raise ValueError(f"Error during query: {result['errors']}")
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+ docs = []
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+ for res in result["data"]["Get"][self._index_name]:
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+ text = res.pop(self._text_key)
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+ docs.append(Document(page_content=text, metadata=res))
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+ return docs
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+
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+ def similarity_search_by_bm25(
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+ self, query: str, k: int = 4, **kwargs: Any
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+ ) -> List[Document]:
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+ """Return docs using BM25F.
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+
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+ Args:
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+ query: Text to look up documents similar to.
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+ k: Number of Documents to return. Defaults to 4.
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+
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+ Returns:
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+ List of Documents most similar to the query.
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+ """
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+ content: Dict[str, Any] = {"concepts": [query]}
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+ if kwargs.get("search_distance"):
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+ content["certainty"] = kwargs.get("search_distance")
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+ query_obj = self._client.query.get(self._index_name, self._query_attrs)
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+ if kwargs.get("where_filter"):
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+ query_obj = query_obj.with_where(kwargs.get("where_filter"))
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+ if kwargs.get("additional"):
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+ query_obj = query_obj.with_additional(kwargs.get("additional"))
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+ result = query_obj.with_bm25(query=content).with_limit(k).do()
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+ if "errors" in result:
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+ raise ValueError(f"Error during query: {result['errors']}")
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+ docs = []
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+ for res in result["data"]["Get"][self._index_name]:
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+ text = res.pop(self._text_key)
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+ docs.append(Document(page_content=text, metadata=res))
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+ return docs
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+
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+ def similarity_search_by_vector(
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+ self, embedding: List[float], k: int = 4, **kwargs: Any
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+ ) -> List[Document]:
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+ """Look up similar documents by embedding vector in Weaviate."""
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+ vector = {"vector": embedding}
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+ query_obj = self._client.query.get(self._index_name, self._query_attrs)
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+ if kwargs.get("where_filter"):
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+ query_obj = query_obj.with_where(kwargs.get("where_filter"))
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+ if kwargs.get("additional"):
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+ query_obj = query_obj.with_additional(kwargs.get("additional"))
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+ result = query_obj.with_near_vector(vector).with_limit(k).do()
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+ if "errors" in result:
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+ raise ValueError(f"Error during query: {result['errors']}")
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+ docs = []
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+ for res in result["data"]["Get"][self._index_name]:
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+ text = res.pop(self._text_key)
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+ docs.append(Document(page_content=text, metadata=res))
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+ return docs
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+
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+ def max_marginal_relevance_search(
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+ self,
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+ query: str,
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+ k: int = 4,
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+ fetch_k: int = 20,
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+ lambda_mult: float = 0.5,
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+ **kwargs: Any,
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+ ) -> List[Document]:
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+ """Return docs selected using the maximal marginal relevance.
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+
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+ Maximal marginal relevance optimizes for similarity to query AND diversity
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+ among selected documents.
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+
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+ Args:
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+ query: Text to look up documents similar to.
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+ k: Number of Documents to return. Defaults to 4.
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+ fetch_k: Number of Documents to fetch to pass to MMR algorithm.
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+ lambda_mult: Number between 0 and 1 that determines the degree
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+ of diversity among the results with 0 corresponding
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+ to maximum diversity and 1 to minimum diversity.
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+ Defaults to 0.5.
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+
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+ Returns:
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+ List of Documents selected by maximal marginal relevance.
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+ """
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+ if self._embedding is not None:
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+ embedding = self._embedding.embed_query(query)
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+ else:
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+ raise ValueError(
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+ "max_marginal_relevance_search requires a suitable Embeddings object"
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+ )
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+
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+ return self.max_marginal_relevance_search_by_vector(
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+ embedding, k=k, fetch_k=fetch_k, lambda_mult=lambda_mult, **kwargs
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+ )
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+
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+ def max_marginal_relevance_search_by_vector(
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+ self,
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+ embedding: List[float],
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+ k: int = 4,
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+ fetch_k: int = 20,
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+ lambda_mult: float = 0.5,
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+ **kwargs: Any,
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+ ) -> List[Document]:
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+ """Return docs selected using the maximal marginal relevance.
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+
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+ Maximal marginal relevance optimizes for similarity to query AND diversity
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+ among selected documents.
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+
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+ Args:
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+ embedding: Embedding to look up documents similar to.
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+ k: Number of Documents to return. Defaults to 4.
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+ fetch_k: Number of Documents to fetch to pass to MMR algorithm.
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+ lambda_mult: Number between 0 and 1 that determines the degree
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+ of diversity among the results with 0 corresponding
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+ to maximum diversity and 1 to minimum diversity.
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+ Defaults to 0.5.
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+
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+ Returns:
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+ List of Documents selected by maximal marginal relevance.
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+ """
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+ vector = {"vector": embedding}
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+ query_obj = self._client.query.get(self._index_name, self._query_attrs)
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+ if kwargs.get("where_filter"):
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+ query_obj = query_obj.with_where(kwargs.get("where_filter"))
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+ results = (
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+ query_obj.with_additional("vector")
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+ .with_near_vector(vector)
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+ .with_limit(fetch_k)
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+ .do()
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+ )
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+
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+ payload = results["data"]["Get"][self._index_name]
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+ embeddings = [result["_additional"]["vector"] for result in payload]
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+ mmr_selected = maximal_marginal_relevance(
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+ np.array(embedding), embeddings, k=k, lambda_mult=lambda_mult
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+ )
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+
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+ docs = []
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+ for idx in mmr_selected:
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+ text = payload[idx].pop(self._text_key)
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+ payload[idx].pop("_additional")
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+ meta = payload[idx]
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+ docs.append(Document(page_content=text, metadata=meta))
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+ return docs
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+
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+ def similarity_search_with_score(
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+ self, query: str, k: int = 4, **kwargs: Any
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+ ) -> List[Tuple[Document, float]]:
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+ """
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+ Return list of documents most similar to the query
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+ text and cosine distance in float for each.
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+ Lower score represents more similarity.
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+ """
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+ if self._embedding is None:
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+ raise ValueError(
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+ "_embedding cannot be None for similarity_search_with_score"
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+ )
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+ content: Dict[str, Any] = {"concepts": [query]}
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+ if kwargs.get("search_distance"):
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+ content["certainty"] = kwargs.get("search_distance")
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+ query_obj = self._client.query.get(self._index_name, self._query_attrs)
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+
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+ embedded_query = self._embedding.embed_query(query)
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+ if not self._by_text:
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+ vector = {"vector": embedded_query}
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+ result = (
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+ query_obj.with_near_vector(vector)
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+ .with_limit(k)
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+ .with_additional("vector")
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+ .do()
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+ )
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+ else:
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+ result = (
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+ query_obj.with_near_text(content)
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+ .with_limit(k)
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+ .with_additional("vector")
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+ .do()
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+ )
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+
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+ if "errors" in result:
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+ raise ValueError(f"Error during query: {result['errors']}")
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+
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+ docs_and_scores = []
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+ for res in result["data"]["Get"][self._index_name]:
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+ text = res.pop(self._text_key)
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+ score = np.dot(res["_additional"]["vector"], embedded_query)
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+ docs_and_scores.append((Document(page_content=text, metadata=res), score))
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+ return docs_and_scores
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+
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+ @classmethod
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+ def from_texts(
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+ cls: Type[Weaviate],
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+ texts: List[str],
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+ embedding: Embeddings,
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+ metadatas: Optional[List[dict]] = None,
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+ **kwargs: Any,
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+ ) -> Weaviate:
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+ """Construct Weaviate wrapper from raw documents.
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+
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+ This is a user-friendly interface that:
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+ 1. Embeds documents.
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+ 2. Creates a new index for the embeddings in the Weaviate instance.
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+ 3. Adds the documents to the newly created Weaviate index.
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+
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+ This is intended to be a quick way to get started.
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+
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+ Example:
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+ .. code-block:: python
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+
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+ from langchain.vectorstores.weaviate import Weaviate
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+ from langchain.embeddings import OpenAIEmbeddings
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+ embeddings = OpenAIEmbeddings()
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+ weaviate = Weaviate.from_texts(
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+ texts,
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+ embeddings,
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+ weaviate_url="http://localhost:8080"
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+ )
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+ """
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+
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+ client = _create_weaviate_client(**kwargs)
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+
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+ from weaviate.util import get_valid_uuid
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+
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+ index_name = kwargs.get("index_name", f"LangChain_{uuid4().hex}")
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+ embeddings = embedding.embed_documents(texts) if embedding else None
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+ text_key = "text"
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+ schema = _default_schema(index_name)
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+ attributes = list(metadatas[0].keys()) if metadatas else None
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+
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+
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+ if not client.schema.contains(schema):
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+ client.schema.create_class(schema)
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+
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+ with client.batch as batch:
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+ for i, text in enumerate(texts):
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+ data_properties = {
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+ text_key: text,
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+ }
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+ if metadatas is not None:
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+ for key in metadatas[i].keys():
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+ data_properties[key] = metadatas[i][key]
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+
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+
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+
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+ if "uuids" in kwargs:
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+ _id = kwargs["uuids"][i]
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+ else:
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+ _id = get_valid_uuid(uuid4())
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+
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+
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+
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+
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+
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+ params = {
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+ "uuid": _id,
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+ "data_object": data_properties,
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+ "class_name": index_name,
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+ }
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+ if embeddings is not None:
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+ params["vector"] = embeddings[i]
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+
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+ batch.add_data_object(**params)
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+
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+ batch.flush()
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+
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+ relevance_score_fn = kwargs.get("relevance_score_fn")
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+ by_text: bool = kwargs.get("by_text", False)
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+
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+ return cls(
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+ client,
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+ index_name,
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+ text_key,
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+ embedding=embedding,
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+ attributes=attributes,
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+ relevance_score_fn=relevance_score_fn,
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+ by_text=by_text,
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+ )
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+
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+ def delete(self, ids: Optional[List[str]] = None, **kwargs: Any) -> None:
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+ """Delete by vector IDs.
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+
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+ Args:
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+ ids: List of ids to delete.
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+ """
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+
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+ if ids is None:
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+ raise ValueError("No ids provided to delete.")
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+
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+
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+ for id in ids:
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+ self._client.data_object.delete(uuid=id)
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