Class SingletonBackwardEngine

src/optimizer/textgrad/config.py:4–43

A singleton class representing the backward engine. This class ensures that only one instance of the backward engine is created and provides methods to set and get the engine.

from typing import Union

class SingletonBackwardEngine:
    """
    A singleton class representing the backward engine.

    This class ensures that only one instance of the backward engine is created and provides methods to set and get the engine."""

    _instance = None

    def __new__(cls):
        if not cls._instance:
            cls._instance = super(SingletonBackwardEngine, cls).__new__(cls)
        return cls._instance

    def __init__(self):
        if not hasattr(self, 'engine'):
            self.engine: EngineLM = None
    
    def set_engine(self, engine: EngineLM, override: bool = False):
        """
        Sets the backward engine.

        :param engine: The backward engine to set.
        :type engine: EngineLM
        :param override: Whether to override the existing engine if it is already set. Defaults to False.
        :type override: bool
        :raises Exception: If the engine is already set and override is False.
        :return: None
        """
        if ((self.engine is not None) and (not override)):
            raise Exception("Engine already set. Use override=True to override cautiously.")
        self.engine = engine

    def get_engine(self):
        """
        Returns the backward engine.

        :return: The backward engine.
        :rtype: EngineLM
        """
        return self.engine

def set_backward_engine(engine: Union[EngineLM, str], override: bool = False, **kwargs):
    singleton_backward_engine = SingletonBackwardEngine()