mirror of
https://github.com/QData/TextAttack.git
synced 2021-10-13 00:05:06 +03:00
37 lines
1.0 KiB
Python
37 lines
1.0 KiB
Python
"""
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chrF Constraints
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--------------------------
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"""
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import nltk.translate.chrf_score
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from textattack.constraints import Constraint
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class chrF(Constraint):
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"""A constraint on chrF (n-gram F-score) difference.
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Args:
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max_chrf (int): Max n-gram F-score allowed.
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compare_against_original (bool): If `True`, compare new `x_adv` against the original `x`.
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Otherwise, compare it against the previous `x_adv`.
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"""
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def __init__(self, max_chrf, compare_against_original=True):
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super().__init__(compare_against_original)
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if not isinstance(max_chrf, int):
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raise TypeError("max_chrf must be an int")
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self.max_chrf = max_chrf
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def _check_constraint(self, transformed_text, reference_text):
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ref = reference_text.words
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hyp = transformed_text.words
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chrf = nltk.translate.chrf_score.sentence_chrf(ref, hyp)
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return chrf <= self.max_chrf
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def extra_repr_keys(self):
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return ["max_chrf"] + super().extra_repr_keys()
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