Source code for textattack.attack_recipes.input_reduction_feng_2018
"""
Input Reduction
====================
(Pathologies of Neural Models Make Interpretations Difficult)
"""
from textattack import Attack
from textattack.constraints.pre_transformation import (
RepeatModification,
StopwordModification,
)
from textattack.goal_functions import InputReduction
from textattack.search_methods import GreedyWordSwapWIR
from textattack.transformations import WordDeletion
from .attack_recipe import AttackRecipe
[docs]class InputReductionFeng2018(AttackRecipe):
"""Feng, Wallace, Grissom, Iyyer, Rodriguez, Boyd-Graber. (2018).
Pathologies of Neural Models Make Interpretations Difficult.
https://arxiv.org/abs/1804.07781
"""
[docs] @staticmethod
def build(model_wrapper):
# At each step, we remove the word with the lowest importance value until
# the model changes its prediction.
transformation = WordDeletion()
constraints = [RepeatModification(), StopwordModification()]
#
# Goal is untargeted classification
#
goal_function = InputReduction(model_wrapper, maximizable=True)
#
# "For each word in an input sentence, we measure its importance by the
# change in the confidence of the original prediction when we remove
# that word from the sentence."
#
# "Instead of looking at the words with high importance values—what
# interpretation methods commonly do—we take a complementary approach
# and study how the model behaves when the supposedly unimportant words are
# removed."
#
search_method = GreedyWordSwapWIR(wir_method="delete")
return Attack(goal_function, constraints, transformation, search_method)