Files
langchain/libs/community/langchain_community/cross_encoders/huggingface.py
Eugene Yurtsev 844955d6e1 community[patch]: assign missed default (#26326)
Assigning missed defaults in various classes. Most clients were being
assigned during the `model_validator(mode="before")` step, so this
change should amount to a no-op in those cases.

---

This PR was autogenerated using gritql

```shell

grit apply 'class_definition(name=$C, $body, superclasses=$S) where {    
    $C <: ! "Config", // Does not work in this scope, but works after class_definition
    $body <: block($statements),
    $statements <: some bubble assignment(left=$x, right=$y, type=$t) as $A where {
        or {
            $y <: `Field($z)`,
            $x <: "model_config"
        }
    },
    // And has either Any or Optional fields without a default
    $statements <: some bubble assignment(left=$x, right=$y, type=$t) as $A where {
        $t <: or {
            r"Optional.*",
            r"Any",
            r"Union[None, .*]",
            r"Union[.*, None, .*]",
            r"Union[.*, None]",
        },
        $y <: ., // Match empty node        
        $t => `$t = None`,
    },    
}
' --language python .

```
2024-09-11 11:13:11 -04:00

65 lines
2.1 KiB
Python

from typing import Any, Dict, List, Tuple
from pydantic import BaseModel, ConfigDict, Field
from langchain_community.cross_encoders.base import BaseCrossEncoder
DEFAULT_MODEL_NAME = "BAAI/bge-reranker-base"
class HuggingFaceCrossEncoder(BaseModel, BaseCrossEncoder):
"""HuggingFace cross encoder models.
Example:
.. code-block:: python
from langchain_community.cross_encoders import HuggingFaceCrossEncoder
model_name = "BAAI/bge-reranker-base"
model_kwargs = {'device': 'cpu'}
hf = HuggingFaceCrossEncoder(
model_name=model_name,
model_kwargs=model_kwargs
)
"""
client: Any = None #: :meta private:
model_name: str = DEFAULT_MODEL_NAME
"""Model name to use."""
model_kwargs: Dict[str, Any] = Field(default_factory=dict)
"""Keyword arguments to pass to the model."""
def __init__(self, **kwargs: Any):
"""Initialize the sentence_transformer."""
super().__init__(**kwargs)
try:
import sentence_transformers
except ImportError as exc:
raise ImportError(
"Could not import sentence_transformers python package. "
"Please install it with `pip install sentence-transformers`."
) from exc
self.client = sentence_transformers.CrossEncoder(
self.model_name, **self.model_kwargs
)
model_config = ConfigDict(extra="forbid", protected_namespaces=())
def score(self, text_pairs: List[Tuple[str, str]]) -> List[float]:
"""Compute similarity scores using a HuggingFace transformer model.
Args:
text_pairs: The list of text text_pairs to score the similarity.
Returns:
List of scores, one for each pair.
"""
scores = self.client.predict(text_pairs)
# Some models e.g bert-multilingual-passage-reranking-msmarco
# gives two score not_relevant and relevant as compare with the query.
if len(scores.shape) > 1: # we are going to get the relevant scores
scores = map(lambda x: x[1], scores)
return scores