| """ | |
| METEOR Constraints | |
| -------------------------- | |
| """ | |
| import nltk | |
| from textattack.constraints import Constraint | |
| class METEOR(Constraint): | |
| """A constraint on METEOR score difference. | |
| Args: | |
| max_meteor (int): Max METEOR score allowed. | |
| compare_against_original (bool): If `True`, compare new `x_adv` against the original `x`. | |
| Otherwise, compare it against the previous `x_adv`. | |
| """ | |
| def __init__(self, max_meteor, compare_against_original=True): | |
| super().__init__(compare_against_original) | |
| if not isinstance(max_meteor, int): | |
| raise TypeError("max_meteor must be an int") | |
| self.max_meteor = max_meteor | |
| def _check_constraint(self, transformed_text, reference_text): | |
| meteor = nltk.translate.meteor([reference_text], transformed_text) | |
| return meteor <= self.max_meteor | |
| def extra_repr_keys(self): | |
| return ["max_meteor"] + super().extra_repr_keys() | |