Index

BaseEmbedding

Bases: TransformComponent

Base class for embeddings.

Source code in llama-index-core/llama_index/core/base/embeddings/base.py

class BaseEmbedding(TransformComponent):
    """Base class for embeddings."""

    model_name: str = Field(
        default="unknown", description="The name of the embedding model."
    )
    embed_batch_size: int = Field(
        default=DEFAULT_EMBED_BATCH_SIZE,
        description="The batch size for embedding calls.",
        gt=0,
        lte=2048,
    )
    callback_manager: CallbackManager = Field(
        default_factory=lambda: CallbackManager([]), exclude=True
    )
    num_workers: Optional[int] = Field(
        default=None,
        description="The number of workers to use for async embedding calls.",
    )

    class Config:
        arbitrary_types_allowed = True

    @validator("callback_manager", pre=True)
    def _validate_callback_manager(
        cls, v: Optional[CallbackManager]
    ) -> CallbackManager:
        if v is None:
            return CallbackManager([])
        return v

    @abstractmethod
    def _get_query_embedding(self, query: str) -> Embedding:
        """
        Embed the input query synchronously.

        Subclasses should implement this method. Reference get_query_embedding's
        docstring for more information.
        """

    @abstractmethod
    async def _aget_query_embedding(self, query: str) -> Embedding:
        """
        Embed the input query asynchronously.

        Subclasses should implement this method. Reference get_query_embedding's
        docstring for more information.
        """

    @dispatcher.span
    def get_query_embedding(self, query: str) -> Embedding:
        """
        Embed the input query.

        When embedding a query, depending on the model, a special instruction
        can be prepended to the raw query string. For example, "Represent the
        question for retrieving supporting documents: ". If you're curious,
        other examples of predefined instructions can be found in
        embeddings/huggingface_utils.py.
        """
        dispatch_event = dispatcher.get_dispatch_event()

        dispatch_event(
            EmbeddingStartEvent(
                model_dict=self.to_dict(),
            )
        )
        with self.callback_manager.event(
            CBEventType.EMBEDDING, payload={EventPayload.SERIALIZED: self.to_dict()}
        ) as event:
            query_embedding = self._get_query_embedding(query)

            event.on_end(
                payload={
                    EventPayload.CHUNKS: [query],
                    EventPayload.EMBEDDINGS: [query_embedding],
                },
            )
        dispatch_event(
            EmbeddingEndEvent(
                chunks=[query],
                embeddings=[query_embedding],
            )
        )
        return query_embedding

    @dispatcher.span
    async def aget_query_embedding(self, query: str) -> Embedding:
        """Get query embedding."""
        dispatch_event = dispatcher.get_dispatch_event()

        dispatch_event(
            EmbeddingStartEvent(
                model_dict=self.to_dict(),
            )
        )
        with self.callback_manager.event(
            CBEventType.EMBEDDING, payload={EventPayload.SERIALIZED: self.to_dict()}
        ) as event:
            query_embedding = await self._aget_query_embedding(query)

            event.on_end(
                payload={
                    EventPayload.CHUNKS: [query],
                    EventPayload.EMBEDDINGS: [query_embedding],
                },
            )
        dispatch_event(
            EmbeddingEndEvent(
                chunks=[query],
                embeddings=[query_embedding],
            )
        )
        return query_embedding

    def get_agg_embedding_from_queries(
        self,
        queries: List[str],
        agg_fn: Optional[Callable[..., Embedding]] = None,
    ) -> Embedding:
        """Get aggregated embedding from multiple queries."""
        query_embeddings = [self.get_query_embedding(query) for query in queries]
        agg_fn = agg_fn or mean_agg
        return agg_fn(query_embeddings)

    async def aget_agg_embedding_from_queries(
        self,
        queries: List[str],
        agg_fn: Optional[Callable[..., Embedding]] = None,
    ) -> Embedding:
        """Async get aggregated embedding from multiple queries."""
        query_embeddings = [await self.aget_query_embedding(query) for query in queries]
        agg_fn = agg_fn or mean_agg
        return agg_fn(query_embeddings)

    @abstractmethod
    def _get_text_embedding(self, text: str) -> Embedding:
        """
        Embed the input text synchronously.

        Subclasses should implement this method. Reference get_text_embedding's
        docstring for more information.
        """

    async def _aget_text_embedding(self, text: str) -> Embedding:
        """
        Embed the input text asynchronously.

        Subclasses can implement this method if there is a true async
        implementation. Reference get_text_embedding's docstring for more
        information.
        """
        # Default implementation just falls back on _get_text_embedding
        return self._get_text_embedding(text)

    def _get_text_embeddings(self, texts: List[str]) -> List[Embedding]:
        """
        Embed the input sequence of text synchronously.

        Subclasses can implement this method if batch queries are supported.
        """
        # Default implementation just loops over _get_text_embedding
        return [self._get_text_embedding(text) for text in texts]

    async def _aget_text_embeddings(self, texts: List[str]) -> List[Embedding]:
        """
        Embed the input sequence of text asynchronously.

        Subclasses can implement this method if batch queries are supported.
        """
        return await asyncio.gather(
            *[self._aget_text_embedding(text) for text in texts]
        )

    @dispatcher.span
    def get_text_embedding(self, text: str) -> Embedding:
        """
        Embed the input text.

        When embedding text, depending on the model, a special instruction
        can be prepended to the raw text string. For example, "Represent the
        document for retrieval: ". If you're curious, other examples of
        predefined instructions can be found in embeddings/huggingface_utils.py.
        """
        dispatch_event = dispatcher.get_dispatch_event()

        dispatch_event(
            EmbeddingStartEvent(
                model_dict=self.to_dict(),
            )
        )
        with self.callback_manager.event(
            CBEventType.EMBEDDING, payload={EventPayload.SERIALIZED: self.to_dict()}
        ) as event:
            text_embedding = self._get_text_embedding(text)

            event.on_end(
                payload={
                    EventPayload.CHUNKS: [text],
                    EventPayload.EMBEDDINGS: [text_embedding],
                }
            )
        dispatch_event(
            EmbeddingEndEvent(
                chunks=[text],
                embeddings=[text_embedding],
            )
        )
        return text_embedding

    @dispatcher.span
    async def aget_text_embedding(self, text: str) -> Embedding:
        """Async get text embedding."""
        dispatch_event = dispatcher.get_dispatch_event()

        dispatch_event(
            EmbeddingStartEvent(
                model_dict=self.to_dict(),
            )
        )
        with self.callback_manager.event(
            CBEventType.EMBEDDING, payload={EventPayload.SERIALIZED: self.to_dict()}
        ) as event:
            text_embedding = await self._aget_text_embedding(text)

            event.on_end(
                payload={
                    EventPayload.CHUNKS: [text],
                    EventPayload.EMBEDDINGS: [text_embedding],
                }
            )
        dispatch_event(
            EmbeddingEndEvent(
                chunks=[text],
                embeddings=[text_embedding],
            )
        )
        return text_embedding

    @dispatcher.span
    def get_text_embedding_batch(
        self,
        texts: List[str],
        show_progress: bool = False,
        **kwargs: Any,
    ) -> List[Embedding]:
        """Get a list of text embeddings, with batching."""
        dispatch_event = dispatcher.get_dispatch_event()

        cur_batch: List[str] = []
        result_embeddings: List[Embedding] = []

        queue_with_progress = enumerate(
            get_tqdm_iterable(texts, show_progress, "Generating embeddings")
        )

        for idx, text in queue_with_progress:
            cur_batch.append(text)
            if idx == len(texts) - 1 or len(cur_batch) == self.embed_batch_size:
                # flush
                dispatch_event(
                    EmbeddingStartEvent(
                        model_dict=self.to_dict(),
                    )
                )
                with self.callback_manager.event(
                    CBEventType.EMBEDDING,
                    payload={EventPayload.SERIALIZED: self.to_dict()},
                ) as event:
                    embeddings = self._get_text_embeddings(cur_batch)
                    result_embeddings.extend(embeddings)
                    event.on_end(
                        payload={
                            EventPayload.CHUNKS: cur_batch,
                            EventPayload.EMBEDDINGS: embeddings,
                        },
                    )
                dispatch_event(
                    EmbeddingEndEvent(
                        chunks=cur_batch,
                        embeddings=embeddings,
                    )
                )
                cur_batch = []

        return result_embeddings

    @dispatcher.span
    async def aget_text_embedding_batch(
        self, texts: List[str], show_progress: bool = False
    ) -> List[Embedding]:
        """Asynchronously get a list of text embeddings, with batching."""
        dispatch_event = dispatcher.get_dispatch_event()
        num_workers = self.num_workers

        cur_batch: List[str] = []
        callback_payloads: List[Tuple[str, List[str]]] = []
        result_embeddings: List[Embedding] = []
        embeddings_coroutines: List[Coroutine] = []
        for idx, text in enumerate(texts):
            cur_batch.append(text)
            if idx == len(texts) - 1 or len(cur_batch) == self.embed_batch_size:
                # flush
                dispatch_event(
                    EmbeddingStartEvent(
                        model_dict=self.to_dict(),
                    )
                )
                event_id = self.callback_manager.on_event_start(
                    CBEventType.EMBEDDING,
                    payload={EventPayload.SERIALIZED: self.to_dict()},
                )
                callback_payloads.append((event_id, cur_batch))
                embeddings_coroutines.append(self._aget_text_embeddings(cur_batch))
                cur_batch = []

        # flatten the results of asyncio.gather, which is a list of embeddings lists
        nested_embeddings = []

        if num_workers and num_workers > 1:
            nested_embeddings = await run_jobs(
                embeddings_coroutines,
                show_progress=show_progress,
                workers=self.num_workers,
                desc="Generating embeddings",
            )
        else:
            if show_progress:
                try:
                    from tqdm.asyncio import tqdm_asyncio

                    nested_embeddings = await tqdm_asyncio.gather(
                        *embeddings_coroutines,
                        total=len(embeddings_coroutines),
                        desc="Generating embeddings",
                    )
                except ImportError:
                    nested_embeddings = await asyncio.gather(*embeddings_coroutines)
            else:
                nested_embeddings = await asyncio.gather(*embeddings_coroutines)

        result_embeddings = [
            embedding for embeddings in nested_embeddings for embedding in embeddings
        ]

        for (event_id, text_batch), embeddings in zip(
            callback_payloads, nested_embeddings
        ):
            dispatch_event(
                EmbeddingEndEvent(
                    chunks=text_batch,
                    embeddings=embeddings,
                )
            )
            self.callback_manager.on_event_end(
                CBEventType.EMBEDDING,
                payload={
                    EventPayload.CHUNKS: text_batch,
                    EventPayload.EMBEDDINGS: embeddings,
                },
                event_id=event_id,
            )

        return result_embeddings

    def similarity(
        self,
        embedding1: Embedding,
        embedding2: Embedding,
        mode: SimilarityMode = SimilarityMode.DEFAULT,
    ) -> float:
        """Get embedding similarity."""
        return similarity(embedding1=embedding1, embedding2=embedding2, mode=mode)

    def __call__(self, nodes: List[BaseNode], **kwargs: Any) -> List[BaseNode]:
        embeddings = self.get_text_embedding_batch(
            [node.get_content(metadata_mode=MetadataMode.EMBED) for node in nodes],
            **kwargs,
        )

        for node, embedding in zip(nodes, embeddings):
            node.embedding = embedding

        return nodes

    async def acall(self, nodes: List[BaseNode], **kwargs: Any) -> List[BaseNode]:
        embeddings = await self.aget_text_embedding_batch(
            [node.get_content(metadata_mode=MetadataMode.EMBED) for node in nodes],
            **kwargs,
        )

        for node, embedding in zip(nodes, embeddings):
            node.embedding = embedding

        return nodes

get_query_embedding

get_query_embedding(query: str) -> Embedding

Embed the input query.

When embedding a query, depending on the model, a special instruction can be prepended to the raw query string. For example, "Represent the question for retrieving supporting documents: ". If you're curious, other examples of predefined instructions can be found in embeddings/huggingface_utils.py.

Source code in llama-index-core/llama_index/core/base/embeddings/base.py

@dispatcher.span
def get_query_embedding(self, query: str) -> Embedding:
    """
    Embed the input query.

    When embedding a query, depending on the model, a special instruction
    can be prepended to the raw query string. For example, "Represent the
    question for retrieving supporting documents: ". If you're curious,
    other examples of predefined instructions can be found in
    embeddings/huggingface_utils.py.
    """
    dispatch_event = dispatcher.get_dispatch_event()

    dispatch_event(
        EmbeddingStartEvent(
            model_dict=self.to_dict(),
        )
    )
    with self.callback_manager.event(
        CBEventType.EMBEDDING, payload={EventPayload.SERIALIZED: self.to_dict()}
    ) as event:
        query_embedding = self._get_query_embedding(query)

        event.on_end(
            payload={
                EventPayload.CHUNKS: [query],
                EventPayload.EMBEDDINGS: [query_embedding],
            },
        )
    dispatch_event(
        EmbeddingEndEvent(
            chunks=[query],
            embeddings=[query_embedding],
        )
    )
    return query_embedding

aget_query_embedding async

aget_query_embedding(query: str) -> Embedding

Get query embedding.

Source code in llama-index-core/llama_index/core/base/embeddings/base.py

@dispatcher.span
async def aget_query_embedding(self, query: str) -> Embedding:
    """Get query embedding."""
    dispatch_event = dispatcher.get_dispatch_event()

    dispatch_event(
        EmbeddingStartEvent(
            model_dict=self.to_dict(),
        )
    )
    with self.callback_manager.event(
        CBEventType.EMBEDDING, payload={EventPayload.SERIALIZED: self.to_dict()}
    ) as event:
        query_embedding = await self._aget_query_embedding(query)

        event.on_end(
            payload={
                EventPayload.CHUNKS: [query],
                EventPayload.EMBEDDINGS: [query_embedding],
            },
        )
    dispatch_event(
        EmbeddingEndEvent(
            chunks=[query],
            embeddings=[query_embedding],
        )
    )
    return query_embedding

get_agg_embedding_from_queries

get_agg_embedding_from_queries(queries: List[str], agg_fn: Optional[Callable[..., Embedding]] = None) -> Embedding

Get aggregated embedding from multiple queries.

Source code in llama-index-core/llama_index/core/base/embeddings/base.py

def get_agg_embedding_from_queries(
    self,
    queries: List[str],
    agg_fn: Optional[Callable[..., Embedding]] = None,
) -> Embedding:
    """Get aggregated embedding from multiple queries."""
    query_embeddings = [self.get_query_embedding(query) for query in queries]
    agg_fn = agg_fn or mean_agg
    return agg_fn(query_embeddings)

aget_agg_embedding_from_queries async

aget_agg_embedding_from_queries(queries: List[str], agg_fn: Optional[Callable[..., Embedding]] = None) -> Embedding

Async get aggregated embedding from multiple queries.

Source code in llama-index-core/llama_index/core/base/embeddings/base.py

async def aget_agg_embedding_from_queries(
    self,
    queries: List[str],
    agg_fn: Optional[Callable[..., Embedding]] = None,
) -> Embedding:
    """Async get aggregated embedding from multiple queries."""
    query_embeddings = [await self.aget_query_embedding(query) for query in queries]
    agg_fn = agg_fn or mean_agg
    return agg_fn(query_embeddings)

get_text_embedding

get_text_embedding(text: str) -> Embedding

Embed the input text.

When embedding text, depending on the model, a special instruction can be prepended to the raw text string. For example, "Represent the document for retrieval: ". If you're curious, other examples of predefined instructions can be found in embeddings/huggingface_utils.py.

Source code in llama-index-core/llama_index/core/base/embeddings/base.py

@dispatcher.span
def get_text_embedding(self, text: str) -> Embedding:
    """
    Embed the input text.

    When embedding text, depending on the model, a special instruction
    can be prepended to the raw text string. For example, "Represent the
    document for retrieval: ". If you're curious, other examples of
    predefined instructions can be found in embeddings/huggingface_utils.py.
    """
    dispatch_event = dispatcher.get_dispatch_event()

    dispatch_event(
        EmbeddingStartEvent(
            model_dict=self.to_dict(),
        )
    )
    with self.callback_manager.event(
        CBEventType.EMBEDDING, payload={EventPayload.SERIALIZED: self.to_dict()}
    ) as event:
        text_embedding = self._get_text_embedding(text)

        event.on_end(
            payload={
                EventPayload.CHUNKS: [text],
                EventPayload.EMBEDDINGS: [text_embedding],
            }
        )
    dispatch_event(
        EmbeddingEndEvent(
            chunks=[text],
            embeddings=[text_embedding],
        )
    )
    return text_embedding

aget_text_embedding async

aget_text_embedding(text: str) -> Embedding

Async get text embedding.

Source code in llama-index-core/llama_index/core/base/embeddings/base.py

@dispatcher.span
async def aget_text_embedding(self, text: str) -> Embedding:
    """Async get text embedding."""
    dispatch_event = dispatcher.get_dispatch_event()

    dispatch_event(
        EmbeddingStartEvent(
            model_dict=self.to_dict(),
        )
    )
    with self.callback_manager.event(
        CBEventType.EMBEDDING, payload={EventPayload.SERIALIZED: self.to_dict()}
    ) as event:
        text_embedding = await self._aget_text_embedding(text)

        event.on_end(
            payload={
                EventPayload.CHUNKS: [text],
                EventPayload.EMBEDDINGS: [text_embedding],
            }
        )
    dispatch_event(
        EmbeddingEndEvent(
            chunks=[text],
            embeddings=[text_embedding],
        )
    )
    return text_embedding

get_text_embedding_batch

get_text_embedding_batch(texts: List[str], show_progress: bool = False, **kwargs: Any) -> List[Embedding]

Get a list of text embeddings, with batching.

Source code in llama-index-core/llama_index/core/base/embeddings/base.py

@dispatcher.span
def get_text_embedding_batch(
    self,
    texts: List[str],
    show_progress: bool = False,
    **kwargs: Any,
) -> List[Embedding]:
    """Get a list of text embeddings, with batching."""
    dispatch_event = dispatcher.get_dispatch_event()

    cur_batch: List[str] = []
    result_embeddings: List[Embedding] = []

    queue_with_progress = enumerate(
        get_tqdm_iterable(texts, show_progress, "Generating embeddings")
    )

    for idx, text in queue_with_progress:
        cur_batch.append(text)
        if idx == len(texts) - 1 or len(cur_batch) == self.embed_batch_size:
            # flush
            dispatch_event(
                EmbeddingStartEvent(
                    model_dict=self.to_dict(),
                )
            )
            with self.callback_manager.event(
                CBEventType.EMBEDDING,
                payload={EventPayload.SERIALIZED: self.to_dict()},
            ) as event:
                embeddings = self._get_text_embeddings(cur_batch)
                result_embeddings.extend(embeddings)
                event.on_end(
                    payload={
                        EventPayload.CHUNKS: cur_batch,
                        EventPayload.EMBEDDINGS: embeddings,
                    },
                )
            dispatch_event(
                EmbeddingEndEvent(
                    chunks=cur_batch,
                    embeddings=embeddings,
                )
            )
            cur_batch = []

    return result_embeddings

aget_text_embedding_batch async

aget_text_embedding_batch(texts: List[str], show_progress: bool = False) -> List[Embedding]

Asynchronously get a list of text embeddings, with batching.

Source code in llama-index-core/llama_index/core/base/embeddings/base.py

@dispatcher.span
async def aget_text_embedding_batch(
    self, texts: List[str], show_progress: bool = False
) -> List[Embedding]:
    """Asynchronously get a list of text embeddings, with batching."""
    dispatch_event = dispatcher.get_dispatch_event()
    num_workers = self.num_workers

    cur_batch: List[str] = []
    callback_payloads: List[Tuple[str, List[str]]] = []
    result_embeddings: List[Embedding] = []
    embeddings_coroutines: List[Coroutine] = []
    for idx, text in enumerate(texts):
        cur_batch.append(text)
        if idx == len(texts) - 1 or len(cur_batch) == self.embed_batch_size:
            # flush
            dispatch_event(
                EmbeddingStartEvent(
                    model_dict=self.to_dict(),
                )
            )
            event_id = self.callback_manager.on_event_start(
                CBEventType.EMBEDDING,
                payload={EventPayload.SERIALIZED: self.to_dict()},
            )
            callback_payloads.append((event_id, cur_batch))
            embeddings_coroutines.append(self._aget_text_embeddings(cur_batch))
            cur_batch = []

    # flatten the results of asyncio.gather, which is a list of embeddings lists
    nested_embeddings = []

    if num_workers and num_workers > 1:
        nested_embeddings = await run_jobs(
            embeddings_coroutines,
            show_progress=show_progress,
            workers=self.num_workers,
            desc="Generating embeddings",
        )
    else:
        if show_progress:
            try:
                from tqdm.asyncio import tqdm_asyncio

                nested_embeddings = await tqdm_asyncio.gather(
                    *embeddings_coroutines,
                    total=len(embeddings_coroutines),
                    desc="Generating embeddings",
                )
            except ImportError:
                nested_embeddings = await asyncio.gather(*embeddings_coroutines)
        else:
            nested_embeddings = await asyncio.gather(*embeddings_coroutines)

    result_embeddings = [
        embedding for embeddings in nested_embeddings for embedding in embeddings
    ]

    for (event_id, text_batch), embeddings in zip(
        callback_payloads, nested_embeddings
    ):
        dispatch_event(
            EmbeddingEndEvent(
                chunks=text_batch,
                embeddings=embeddings,
            )
        )
        self.callback_manager.on_event_end(
            CBEventType.EMBEDDING,
            payload={
                EventPayload.CHUNKS: text_batch,
                EventPayload.EMBEDDINGS: embeddings,
            },
            event_id=event_id,
        )

    return result_embeddings

similarity

similarity(embedding1: Embedding, embedding2: Embedding, mode: SimilarityMode = SimilarityMode.DEFAULT) -> float

Get embedding similarity.

Source code in llama-index-core/llama_index/core/base/embeddings/base.py

def similarity(
    self,
    embedding1: Embedding,
    embedding2: Embedding,
    mode: SimilarityMode = SimilarityMode.DEFAULT,
) -> float:
    """Get embedding similarity."""
    return similarity(embedding1=embedding1, embedding2=embedding2, mode=mode)

resolve_embed_model

resolve_embed_model(embed_model: Optional[EmbedType] = None, callback_manager: Optional[CallbackManager] = None) -> BaseEmbedding

Resolve embed model.

Source code in llama-index-core/llama_index/core/embeddings/utils.py

def resolve_embed_model(
    embed_model: Optional[EmbedType] = None,
    callback_manager: Optional[CallbackManager] = None,
) -> BaseEmbedding:
    """Resolve embed model."""
    from llama_index.core.settings import Settings

    try:
        from llama_index.core.bridge.langchain import Embeddings as LCEmbeddings
    except ImportError:
        LCEmbeddings = None  # type: ignore

    if embed_model == "default":
        if os.getenv("IS_TESTING"):
            embed_model = MockEmbedding(embed_dim=8)
            embed_model.callback_manager = callback_manager or Settings.callback_manager
            return embed_model

        try:
            from llama_index.embeddings.openai import (
                OpenAIEmbedding,
            )  # pants: no-infer-dep

            from llama_index.embeddings.openai.utils import (
                validate_openai_api_key,
            )  # pants: no-infer-dep

            embed_model = OpenAIEmbedding()
            validate_openai_api_key(embed_model.api_key)
        except ImportError:
            raise ImportError(
                "`llama-index-embeddings-openai` package not found, "
                "please run `pip install llama-index-embeddings-openai`"
            )
        except ValueError as e:
            raise ValueError(
                "\n******\n"
                "Could not load OpenAI embedding model. "
                "If you intended to use OpenAI, please check your OPENAI_API_KEY.\n"
                "Original error:\n"
                f"{e!s}"
                "\nConsider using embed_model='local'.\n"
                "Visit our documentation for more embedding options: "
                "https://docs.llamaindex.ai/en/stable/module_guides/models/"
                "embeddings.html#modules"
                "\n******"
            )
    # for image multi-modal embeddings
    elif isinstance(embed_model, str) and embed_model.startswith("clip"):
        try:
            from llama_index.embeddings.clip import ClipEmbedding  # pants: no-infer-dep

            clip_model_name = (
                embed_model.split(":")[1] if ":" in embed_model else "ViT-B/32"
            )
            embed_model = ClipEmbedding(model_name=clip_model_name)
        except ImportError as e:
            raise ImportError(
                "`llama-index-embeddings-clip` package not found, "
                "please run `pip install llama-index-embeddings-clip` and `pip install git+https://github.com/openai/CLIP.git`"
            )

    if isinstance(embed_model, str):
        try:
            from llama_index.embeddings.huggingface import (
                HuggingFaceEmbedding,
            )  # pants: no-infer-dep

            splits = embed_model.split(":", 1)
            is_local = splits[0]
            model_name = splits[1] if len(splits) > 1 else None
            if is_local != "local":
                raise ValueError(
                    "embed_model must start with str 'local' or of type BaseEmbedding"
                )

            cache_folder = os.path.join(get_cache_dir(), "models")
            os.makedirs(cache_folder, exist_ok=True)

            embed_model = HuggingFaceEmbedding(
                model_name=model_name, cache_folder=cache_folder
            )
        except ImportError:
            raise ImportError(
                "`llama-index-embeddings-huggingface` package not found, "
                "please run `pip install llama-index-embeddings-huggingface`"
            )

    if LCEmbeddings is not None and isinstance(embed_model, LCEmbeddings):
        try:
            from llama_index.embeddings.langchain import (
                LangchainEmbedding,
            )  # pants: no-infer-dep

            embed_model = LangchainEmbedding(embed_model)
        except ImportError as e:
            raise ImportError(
                "`llama-index-embeddings-langchain` package not found, "
                "please run `pip install llama-index-embeddings-langchain`"
            )

    if embed_model is None:
        print("Embeddings have been explicitly disabled. Using MockEmbedding.")
        embed_model = MockEmbedding(embed_dim=1)

    embed_model.callback_manager = callback_manager or Settings.callback_manager

    return embed_model