# Empty vector when adding cross references (ref2vec-centroid) **URL:** \ **Category:** Support\ **Tags:** technical\ **Created:** [January 4, 2025, 7:16pm UTC](https://forum.weaviate.io/t/empty-vector-when-adding-cross-references-ref2vec-centroid/9564 "2025-01-04T19:16:58Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Bohdan\_Klishchov](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.weaviate.io/bohdan_klishchov/32/3296_2.png) [@Bohdan\_Klishchov](https://forum.weaviate.io/u/Bohdan_Klishchov)\ **Post date:** [January 4, 2025, 7:16pm UTC](https://forum.weaviate.io/t/empty-vector-when-adding-cross-references-ref2vec-centroid/9564/1 "2025-01-04T19:16:58Z")
My collections: ```await "Short", properties=[ Property( name=ShortProps.ID.value, data_type=DataType.INT, description="Unique identifier for the short.", skip_vectorization=True, ), Property( name=ShortProps.HASH_NAME.value, data_type=DataType.TEXT, description="Unique content hash name for the short.", skip_vectorization=True, ), Property( name=ShortProps.DESCRIPTION.value, data_type=DataType.TEXT, description="Short description of the content.", ), Property( name=ShortProps.CATEGORY.value, data_type=DataType.TEXT, description="Category of the short.", ), Property( name=ShortProps.CONTENT.value, data_type=DataType.BLOB, description="Content of the short (e.g., video, image)." ), ], vectorizer_config=[ # Set a named vector Configure.NamedVectors.multi2vec_bind( name="shorts_vec", text_fields=[ Multi2VecField(name=ShortProps.DESCRIPTION.value, weight=0.3), Multi2VecField(name=ShortProps.CATEGORY.value, weight=0.2), ], # video_fields=[ # Multi2VecField(name=ShortProps.CONTENT.value, weight=0.5), # ], ), ], ) await cls.client.collections.create( "UserInteractions", properties=[ Property( name=UserInteractionsProps.ID.value, data_type=DataType.INT, description="Unique identifier for the user." ), ], references=[ ReferenceProperty( name=UserInteractionsProps.LIKED_SHORTS.value, target_collection="Short", description="Short which liked by current user", ), ], vectorizer_config=[ Configure.NamedVectors.ref2vec_centroid( name="liked_vector", reference_properties=[ UserInteractionsProps.LIKED_SHORTS.value, ], ), ], ) ``` I tried add cross-references like this: ```auto async def create_interaction( self, user_interactions_uuid: UUID, short_uuid: UUID, interaction_type: InteractionType, ) -> None: await self.collection.data.reference_add( from_uuid=user_interactions_uuid, from_property=interaction_type_property[interaction_type.value], to=short_uuid ) ``` but got object with empty vector: ```auto Object(uuid=_WeaviateUUIDInt('ede63ad5-ae6b-4041-be34-1db9864177c7'), metadata=MetadataReturn(creation_time=None, last_update_time=None, distance=None, certainty=None, score=None, explain_score=None, is_consistent=None, rerank_score=None), properties={'object_id': 2}, references={'liked_shorts': }, vector={'liked_vector': []}, collection='UserInteractions') ``` ---
**Author:** ![DudaNogueira](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.weaviate.io/dudanogueira/32/7846_2.png) [@DudaNogueira](https://forum.weaviate.io/u/DudaNogueira)\ **Post date:** [January 6, 2025, 2:08pm UTC](https://forum.weaviate.io/t/empty-vector-when-adding-cross-references-ref2vec-centroid/9564/2 "2025-01-06T14:08:34Z")
hi @Bohdan_Klishchov !! Welcome to our community 🤗 Can you share a full running code? This has proven more efficient to discover this kind of issue as sometimes the issue is on underlying code that is not share 😬 Here we have a set of recipes here, that can serve as base for this: > **[GitHub - weaviate/recipes: This repository shares end-to-end notebooks on how...](https://github.com/weaviate/recipes)** > > This repository shares end-to-end notebooks on how to use various Weaviate features and integrations! I have searched, and there isn’t a recipe for ref2vec-centroid 😬 Maybe we can create one 🙂 Thanks! ---
**Author:** ![Bohdan\_Klishchov](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.weaviate.io/bohdan_klishchov/32/3296_2.png) [@Bohdan\_Klishchov](https://forum.weaviate.io/u/Bohdan_Klishchov)\ **Post date:** [January 6, 2025, 3:31pm UTC](https://forum.weaviate.io/t/empty-vector-when-adding-cross-references-ref2vec-centroid/9564/3 "2025-01-06T15:31:26Z")
hello @DudaNogueira I simplified my code: ```import import asyncio import weaviate from weaviate.classes.config import Configure from weaviate.client import WeaviateAsyncClient from weaviate.collections.classes.grpc import QueryReference from weaviate.collections.classes.config_vectorizers import Multi2VecField from weaviate.collections.classes.config import Property, DataType, ReferenceProperty from core.settings import get_settings settings = get_settings() async def init_collections(client: WeaviateAsyncClient): if await client.collections.exists('Short'): return if await client.collections.exists('UserInteractions'): return await client.collections.create( "Short", properties=[ Property( name='object_id', data_type=DataType.INT, description="Unique identifier for the short.", skip_vectorization=True, ), Property( name='description', data_type=DataType.TEXT, description="Short description of the content.", ), Property( name='category', data_type=DataType.TEXT, description="Category of the short.", ), ], vectorizer_config=[ # Set a named vector Configure.NamedVectors.multi2vec_bind( name="shorts_vec", text_fields=[ Multi2VecField(name='description', weight=0.6), Multi2VecField(name='category', weight=0.4), ] ), ], ) await client.collections.create( "UserInteractions", properties=[ Property( name='object_id', data_type=DataType.INT, description="Unique identifier for the user." ), ], references=[ ReferenceProperty( name='liked_shorts', target_collection="Short", description="Short which liked by current user", ), ], vectorizer_config=Configure.Vectorizer.ref2vec_centroid( reference_properties=[ 'liked_shorts' ] ), ) async def main(): client: WeaviateAsyncClient = weaviate.use_async_with_local( host=settings.WEAVIATE_HOST, port=settings.WEAVIATE_PORT, skip_init_checks=True ) await client.connect() try: await init_collections(client=client) short_collection = client.collections.get('Short') user_collection = client.collections.get('UserInteractions') short_uuid = await short_collection.data.insert(properties={ 'object_id': 1, 'description': 'description1', 'category': 'category1' }, uuid=uuid.uuid4()) print(f'created short: {short_uuid}') user_uuid = await user_collection.data.insert(properties={'object_id': 1}, uuid=uuid.uuid4()) print(f'created user: {user_uuid}') # creating cross-reference await user_collection.data.reference_add( from_uuid=user_uuid, from_property='liked_shorts', to=short_uuid ) resp = await user_collection.query.fetch_object_by_id( uuid=user_uuid, include_vector=True, return_references=QueryReference( link_on='liked_shorts', return_properties=["object_id"], ), ) print(resp) finally: await client.close() if __name__ == ' __main__': asyncio.run(main()) ``` got this output: ```auto created short: 09e06d77-a1f6-4274-b0ae-485f532322fd created user: 0c6ff736-ef4a-45e9-9e34-93ff67a53dfe ObjectSingleReturn(uuid=_WeaviateUUIDInt('0c6ff736-ef4a-45e9-9e34-93ff67a53dfe'), metadata=MetadataSingleObjectReturn(creation_time=datetime.datetime(2025, 1, 6, 15, 20, 12, 837000, tzinfo=datetime.timezone.utc), last_update_time=datetime.datetime(2025, 1, 6, 15, 20, 12, 840000, tzinfo=datetime.timezone.utc), is_consistent=None), properties={'object_id': 1}, references={'liked_shorts': }, vector={}, collection='UserInteractions') ``` i use python 3.11 and weaviate-client 4.9.6 for me asynchronicity is important, so I can’t downgrade to the old 3rd client, where it is not supported, even if there are more examples thank you for your reply p.s. I’m working on a recommendation system