langchain/embeddings/aleph_alpha.py

from typing import Any, Dict, List, Optional

from langchain_core.embeddings import Embeddings
from langchain_core.pydantic_v1 import BaseModel, root_validator

from langchain.utils import get_from_dict_or_env


class AlephAlphaAsymmetricSemanticEmbedding(BaseModel, Embeddings):
    """Aleph Alpha's asymmetric semantic embedding.

    AA provides you with an endpoint to embed a document and a query.
    The models were optimized to make the embeddings of documents and
    the query for a document as similar as possible.
    To learn more, check out: https://docs.aleph-alpha.com/docs/tasks/semantic_embed/

    Example:
        .. code-block:: python
            from aleph_alpha import AlephAlphaAsymmetricSemanticEmbedding

            embeddings = AlephAlphaAsymmetricSemanticEmbedding(
                normalize=True, compress_to_size=128
            )

            document = "This is a content of the document"
            query = "What is the content of the document?"

            doc_result = embeddings.embed_documents([document])
            query_result = embeddings.embed_query(query)

    """

    client: Any  #: :meta private:

    # Embedding params
    model: str = "luminous-base"
    """Model name to use."""
    compress_to_size: Optional[int] = None
    """Should the returned embeddings come back as an original 5120-dim vector, 
    or should it be compressed to 128-dim."""
    normalize: Optional[bool] = None
    """Should returned embeddings be normalized"""
    contextual_control_threshold: Optional[int] = None
    """Attention control parameters only apply to those tokens that have 
    explicitly been set in the request."""
    control_log_additive: bool = True
    """Apply controls on prompt items by adding the log(control_factor) 
    to attention scores."""

    # Client params
    aleph_alpha_api_key: Optional[str] = None
    """API key for Aleph Alpha API."""
    host: str = "https://api.aleph-alpha.com"
    """The hostname of the API host. 
    The default one is "https://api.aleph-alpha.com")"""
    hosting: Optional[str] = None
    """Determines in which datacenters the request may be processed.
    You can either set the parameter to "aleph-alpha" or omit it (defaulting to None).
    Not setting this value, or setting it to None, gives us maximal flexibility 
    in processing your request in our
    own datacenters and on servers hosted with other providers. 
    Choose this option for maximal availability.
    Setting it to "aleph-alpha" allows us to only process the request 
    in our own datacenters.
    Choose this option for maximal data privacy."""
    request_timeout_seconds: int = 305
    """Client timeout that will be set for HTTP requests in the 
    `requests` library's API calls.
    Server will close all requests after 300 seconds with an internal server error."""
    total_retries: int = 8
    """The number of retries made in case requests fail with certain retryable 
    status codes. If the last
    retry fails a corresponding exception is raised. Note, that between retries 
    an exponential backoff
    is applied, starting with 0.5 s after the first retry and doubling for each 
    retry made. So with the
    default setting of 8 retries a total wait time of 63.5 s is added between 
    the retries."""
    nice: bool = False
    """Setting this to True, will signal to the API that you intend to be 
    nice to other users
    by de-prioritizing your request below concurrent ones."""

    @root_validator()
    def validate_environment(cls, values: Dict) -> Dict:
        """Validate that api key and python package exists in environment."""
        aleph_alpha_api_key = get_from_dict_or_env(
            values, "aleph_alpha_api_key", "ALEPH_ALPHA_API_KEY"
        )
        try:
            from aleph_alpha_client import Client

            values["client"] = Client(
                token=aleph_alpha_api_key,
                host=values["host"],
                hosting=values["hosting"],
                request_timeout_seconds=values["request_timeout_seconds"],
                total_retries=values["total_retries"],
                nice=values["nice"],
            )
        except ImportError:
            raise ValueError(
                "Could not import aleph_alpha_client python package. "
                "Please install it with `pip install aleph_alpha_client`."
            )

        return values

    def embed_documents(self, texts: List[str]) -> List[List[float]]:
        """Call out to Aleph Alpha's asymmetric Document endpoint.

        Args:
            texts: The list of texts to embed.

        Returns:
            List of embeddings, one for each text.
        """
        try:
            from aleph_alpha_client import (
                Prompt,
                SemanticEmbeddingRequest,
                SemanticRepresentation,
            )
        except ImportError:
            raise ValueError(
                "Could not import aleph_alpha_client python package. "
                "Please install it with `pip install aleph_alpha_client`."
            )
        document_embeddings = []

        for text in texts:
            document_params = {
                "prompt": Prompt.from_text(text),
                "representation": SemanticRepresentation.Document,
                "compress_to_size": self.compress_to_size,
                "normalize": self.normalize,
                "contextual_control_threshold": self.contextual_control_threshold,
                "control_log_additive": self.control_log_additive,
            }

            document_request = SemanticEmbeddingRequest(**document_params)
            document_response = self.client.semantic_embed(
                request=document_request, model=self.model
            )

            document_embeddings.append(document_response.embedding)

        return document_embeddings

    def embed_query(self, text: str) -> List[float]:
        """Call out to Aleph Alpha's asymmetric, query embedding endpoint
        Args:
            text: The text to embed.

        Returns:
            Embeddings for the text.
        """
        try:
            from aleph_alpha_client import (
                Prompt,
                SemanticEmbeddingRequest,
                SemanticRepresentation,
            )
        except ImportError:
            raise ValueError(
                "Could not import aleph_alpha_client python package. "
                "Please install it with `pip install aleph_alpha_client`."
            )
        symmetric_params = {
            "prompt": Prompt.from_text(text),
            "representation": SemanticRepresentation.Query,
            "compress_to_size": self.compress_to_size,
            "normalize": self.normalize,
            "contextual_control_threshold": self.contextual_control_threshold,
            "control_log_additive": self.control_log_additive,
        }

        symmetric_request = SemanticEmbeddingRequest(**symmetric_params)
        symmetric_response = self.client.semantic_embed(
            request=symmetric_request, model=self.model
        )

        return symmetric_response.embedding


class AlephAlphaSymmetricSemanticEmbedding(AlephAlphaAsymmetricSemanticEmbedding):
    """The symmetric version of the Aleph Alpha's semantic embeddings.

    The main difference is that here, both the documents and
    queries are embedded with a SemanticRepresentation.Symmetric
    Example:
        .. code-block:: python

            from aleph_alpha import AlephAlphaSymmetricSemanticEmbedding

            embeddings = AlephAlphaAsymmetricSemanticEmbedding(
                normalize=True, compress_to_size=128
            )
            text = "This is a test text"

            doc_result = embeddings.embed_documents([text])
            query_result = embeddings.embed_query(text)
    """

    def _embed(self, text: str) -> List[float]:
        try:
            from aleph_alpha_client import (
                Prompt,
                SemanticEmbeddingRequest,
                SemanticRepresentation,
            )
        except ImportError:
            raise ValueError(
                "Could not import aleph_alpha_client python package. "
                "Please install it with `pip install aleph_alpha_client`."
            )
        query_params = {
            "prompt": Prompt.from_text(text),
            "representation": SemanticRepresentation.Symmetric,
            "compress_to_size": self.compress_to_size,
            "normalize": self.normalize,
            "contextual_control_threshold": self.contextual_control_threshold,
            "control_log_additive": self.control_log_additive,
        }

        query_request = SemanticEmbeddingRequest(**query_params)
        query_response = self.client.semantic_embed(
            request=query_request, model=self.model
        )

        return query_response.embedding

    def embed_documents(self, texts: List[str]) -> List[List[float]]:
        """Call out to Aleph Alpha's Document endpoint.

        Args:
            texts: The list of texts to embed.

        Returns:
            List of embeddings, one for each text.
        """
        document_embeddings = []

        for text in texts:
            document_embeddings.append(self._embed(text))
        return document_embeddings

    def embed_query(self, text: str) -> List[float]:
        """Call out to Aleph Alpha's asymmetric, query embedding endpoint
        Args:
            text: The text to embed.

        Returns:
            Embeddings for the text.
        """
        return self._embed(text)