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""" |
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Search Method Abstract Class |
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=============================== |
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""" |
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from abc import ABC, abstractmethod |
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from textattack.shared.utils import ReprMixin |
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class SearchMethod(ReprMixin, ABC): |
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"""This is an abstract class that contains main helper functionality for |
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search methods. |
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A search method is a strategy for applying transformations until the |
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goal is met or the search is exhausted. |
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""" |
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def __call__(self, initial_result): |
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"""Ensures access to necessary functions, then calls |
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``perform_search``""" |
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if not hasattr(self, "get_transformations"): |
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raise AttributeError( |
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"Search Method must have access to get_transformations method" |
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) |
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if not hasattr(self, "get_goal_results"): |
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raise AttributeError( |
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"Search Method must have access to get_goal_results method" |
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) |
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if not hasattr(self, "filter_transformations"): |
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raise AttributeError( |
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"Search Method must have access to filter_transformations method" |
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) |
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result = self.perform_search(initial_result) |
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result.num_queries = self.goal_function.num_queries |
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return result |
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@abstractmethod |
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def perform_search(self, initial_result): |
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"""Perturbs `attacked_text` from ``initial_result`` until goal is |
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reached or search is exhausted. |
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Must be overridden by specific search methods. |
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""" |
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raise NotImplementedError() |
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def check_transformation_compatibility(self, transformation): |
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"""Determines whether this search method is compatible with |
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``transformation``.""" |
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return True |
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@property |
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def is_black_box(self): |
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"""Returns `True` if search method does not require access to victim |
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model's internal states.""" |
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raise NotImplementedError() |
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def get_victim_model(self): |
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if self.is_black_box: |
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raise NotImplementedError( |
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"Cannot access victim model if search method is a black-box method." |
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) |
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else: |
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return self.goal_function.model |
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