mirror of
https://github.com/QData/TextAttack.git
synced 2021-10-13 00:05:06 +03:00
44 lines
1.3 KiB
Python
44 lines
1.3 KiB
Python
import functools
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import numpy as np
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from textattack.shared.utils import words_from_text
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from .text_to_text_goal_function import TextToTextGoalFunction
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class NonOverlappingOutput(TextToTextGoalFunction):
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"""
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Ensures that none of the words at a position are equal.
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Defined in seq2sick (https://arxiv.org/pdf/1803.01128.pdf), equation (3).
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"""
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def _is_goal_complete(self, model_output, _):
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return self._get_score(model_output, self.ground_truth_output) == 1.0
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def _get_score(self, model_output, _):
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num_words_diff = word_difference_score(model_output, self.ground_truth_output)
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if num_words_diff == 0:
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return 0.0
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else:
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return num_words_diff / len(get_words_cached(self.ground_truth_output))
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@functools.lru_cache(maxsize=2 ** 12)
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def get_words_cached(s):
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return np.array(words_from_text(s))
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@functools.lru_cache(maxsize=2 ** 12)
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def word_difference_score(s1, s2):
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""" Returns the number of words that are non-overlapping between s1 and s2. """
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s1_words = get_words_cached(s1)
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s2_words = get_words_cached(s2)
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min_length = min(len(s1_words), len(s2_words))
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if min_length == 0:
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return 0
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s1_words = s1_words[:min_length]
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s2_words = s2_words[:min_length]
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return (s1_words != s2_words).sum()
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