Spaces:
Sleeping
Sleeping
| """ | |
| chrF Constraints | |
| -------------------------- | |
| """ | |
| import nltk.translate.chrf_score | |
| from textattack.constraints import Constraint | |
| class chrF(Constraint): | |
| """A constraint on chrF (n-gram F-score) difference. | |
| Args: | |
| max_chrf (int): Max n-gram F-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_chrf, compare_against_original=True): | |
| super().__init__(compare_against_original) | |
| if not isinstance(max_chrf, int): | |
| raise TypeError("max_chrf must be an int") | |
| self.max_chrf = max_chrf | |
| def _check_constraint(self, transformed_text, reference_text): | |
| ref = reference_text.words | |
| hyp = transformed_text.words | |
| chrf = nltk.translate.chrf_score.sentence_chrf(ref, hyp) | |
| return chrf <= self.max_chrf | |
| def extra_repr_keys(self): | |
| return ["max_chrf"] + super().extra_repr_keys() | |