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langchain/langchain/chains/llm_math/base.py

72 lines
2.1 KiB
Python

"""Chain that interprets a prompt and executes python code to do math."""
from typing import Dict, List
from pydantic import BaseModel, Extra
from langchain.chains.base import Chain
from langchain.chains.llm import LLMChain
from langchain.chains.llm_math.prompt import PROMPT
from langchain.input import print_text
from langchain.llms.base import BaseLLM
from langchain.python import PythonREPL
class LLMMathChain(Chain, BaseModel):
"""Chain that interprets a prompt and executes python code to do math.
Example:
.. code-block:: python
from langchain import LLMMathChain, OpenAI
llm_math = LLMMathChain(llm=OpenAI())
"""
llm: BaseLLM
"""LLM wrapper to use."""
input_key: str = "question" #: :meta private:
output_key: str = "answer" #: :meta private:
class Config:
"""Configuration for this pydantic object."""
extra = Extra.forbid
arbitrary_types_allowed = True
@property
def input_keys(self) -> List[str]:
"""Expect input key.
:meta private:
"""
return [self.input_key]
@property
def output_keys(self) -> List[str]:
"""Expect output key.
:meta private:
"""
return [self.output_key]
def _call(self, inputs: Dict[str, str]) -> Dict[str, str]:
llm_executor = LLMChain(prompt=PROMPT, llm=self.llm)
python_executor = PythonREPL()
if self.verbose:
print_text(inputs[self.input_key])
t = llm_executor.predict(question=inputs[self.input_key], stop=["```output"])
if self.verbose:
print_text(t, color="green")
t = t.strip()
if t.startswith("```python"):
code = t[9:-4]
output = python_executor.run(code)
if self.verbose:
print_text("\nAnswer: ")
print_text(output, color="yellow")
answer = "Answer: " + output
elif t.startswith("Answer:"):
answer = t
else:
raise ValueError(f"unknown format from LLM: {t}")
return {self.output_key: answer}