substract_constant

class SubstractConstant(OneToOneInversableDerivableTransformer):
    """Tranform series by substracting a constant.

    ```math
        serie-value
    ```

    Args:
        value (float): Value to substract.
    """

    def __init__(self, value: float) -> None:
        self.value = value

    @property
    def parameters(self) -> Dict[str, float]:
        return self.__dict__

    # ------- METHODS -------

    def transform(self, serie: np.ndarray, copy=False) -> np.ndarray:
        serie = super().transform(serie, copy)

        return self._transformer(serie, self.value)

    def inverse_transform(self, serie: np.ndarray, copy=False) -> np.ndarray:
        serie = super().inverse_transform(serie, copy)

        return self._inverse_transformer(serie, self.value)

    def derivative_transform(self, serie: np.ndarray, copy=False) -> np.ndarray:
        serie = super().derivative_transform(serie, copy)

        return self._derivative_transformer(serie, self.value)

    # ------- TRANSFORMERS -------

    @staticmethod
    def _transformer(serie: np.ndarray, value) -> np.ndarray:
        return serie - value

    @staticmethod
    def _inverse_transformer(serie: np.ndarray, value) -> np.ndarray:
        return serie + value

    @staticmethod
    def _derivative_transformer(serie: np.ndarray, value) -> np.ndarray:
        return np.array([0] * len(serie))

    # ------- CHECKERS -------

    def check_params(self, serie: np.ndarray):
        """Check if parameters respect their application scope."""
        if not (self.value != np.inf and self.value != -np.inf):
            raise ParameterScopeException(
                f"The parameter 'value' should be different than infinite. value: {self.value}."
            )