langchain/libs/experimental/langchain_experimental/llms/rellm_decoder.py
Nuno Campos c0d67420e5
Use a submodule for pydantic v1 compat (#9371)
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2023-08-17 16:35:49 +01:00

71 lines
2.1 KiB
Python

"""Experimental implementation of RELLM wrapped LLM."""
from __future__ import annotations
from typing import TYPE_CHECKING, Any, List, Optional, cast
from langchain.callbacks.manager import CallbackManagerForLLMRun
from langchain.llms.huggingface_pipeline import HuggingFacePipeline
from langchain.llms.utils import enforce_stop_tokens
from langchain_experimental.pydantic_v1 import Field, root_validator
if TYPE_CHECKING:
import rellm
from regex import Pattern as RegexPattern
else:
try:
from regex import Pattern as RegexPattern
except ImportError:
pass
def import_rellm() -> rellm:
"""Lazily import rellm."""
try:
import rellm
except ImportError:
raise ImportError(
"Could not import rellm python package. "
"Please install it with `pip install rellm`."
)
return rellm
class RELLM(HuggingFacePipeline):
"""RELLM wrapped LLM using HuggingFace Pipeline API."""
regex: RegexPattern = Field(..., description="The structured format to complete.")
max_new_tokens: int = Field(
default=200, description="Maximum number of new tokens to generate."
)
@root_validator
def check_rellm_installation(cls, values: dict) -> dict:
import_rellm()
return values
def _call(
self,
prompt: str,
stop: Optional[List[str]] = None,
run_manager: Optional[CallbackManagerForLLMRun] = None,
**kwargs: Any,
) -> str:
rellm = import_rellm()
from transformers import Text2TextGenerationPipeline
pipeline = cast(Text2TextGenerationPipeline, self.pipeline)
text = rellm.complete_re(
prompt,
self.regex,
tokenizer=pipeline.tokenizer,
model=pipeline.model,
max_new_tokens=self.max_new_tokens,
)
if stop is not None:
# This is a bit hacky, but I can't figure out a better way to enforce
# stop tokens when making calls to huggingface_hub.
text = enforce_stop_tokens(text, stop)
return text