OpenBackdoor

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from .poisoner import Poisoner
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import torch
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import torch.nn as nn
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from typing import *
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from collections import defaultdict
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from openbackdoor.utils import logger
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import random
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class EPPoisoner(Poisoner):
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    r"""
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        Poisoner for `EP <https://aclanthology.org/2021.naacl-main.165/>`_
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    Args:
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        triggers (`List[str]`, optional): The triggers to insert in texts. Default to `['cf', 'mn', 'bb', 'tq', 'mb']`.
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        num_triggers (`int`, optional): Number of triggers to insert. Default to 2.
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    """
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    def __init__(
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        self,
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        triggers: Optional[List[str]] = ["cf", "mn", "bb", "tq", "mb"],
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        num_triggers: Optional[int] = 2,
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        **kwargs,
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    ):
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        super().__init__(**kwargs)
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        self.triggers = triggers
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        self.num_triggers = num_triggers
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        logger.info("Initializing EP poisoner, triggers are {}".format(" ".join(self.triggers)))
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    def poison(self, data: list):
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        poisoned = []
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        for text, label, poison_label in data:
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            poisoned.append((self.insert(text), self.target_label, 1))
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        return poisoned
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    def insert(
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        self, 
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        text: str, 
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    ):
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        r"""
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            Insert trigger(s) randomly in a sentence.
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        Args:
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            text (`str`): Sentence to insert trigger(s).
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        """
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        words = text.split()
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        for _ in range(self.num_triggers):
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            insert_word = random.choice(self.triggers)
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            position = random.randint(0, len(words))
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            words.insert(position, insert_word)
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        return " ".join(words)
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