Dialogue for Prompting: a Policy-Gradient-Based Discrete Prompt Generation for Few-shot Learning

Fuente: arXiv
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Main Authors: Li, Chengzhengxu, Liu, Xiaoming, Wang, Yichen, Li, Duyi, Lan, Yu, Shen, Chao
Format: Preprint
Published: 2023
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author Li, Chengzhengxu
Liu, Xiaoming
Wang, Yichen
Li, Duyi
Lan, Yu
Shen, Chao
author_facet Li, Chengzhengxu
Liu, Xiaoming
Wang, Yichen
Li, Duyi
Lan, Yu
Shen, Chao
contents Prompt-based pre-trained language models (PLMs) paradigm have succeeded substantially in few-shot natural language processing (NLP) tasks. However, prior discrete prompt optimization methods require expert knowledge to design the base prompt set and identify high-quality prompts, which is costly, inefficient, and subjective. Meanwhile, existing continuous prompt optimization methods improve the performance by learning the ideal prompts through the gradient information of PLMs, whose high computational cost, and low readability and generalizability are often concerning. To address the research gap, we propose a Dialogue-comprised Policy-gradient-based Discrete Prompt Optimization ($DP_2O$) method. We first design a multi-round dialogue alignment strategy for readability prompt set generation based on GPT-4. Furthermore, we propose an efficient prompt screening metric to identify high-quality prompts with linear complexity. Finally, we construct a reinforcement learning (RL) framework based on policy gradients to match the prompts to inputs optimally. By training a policy network with only 0.67% of the PLM parameter size on the tasks in the few-shot setting, $DP_2O$ outperforms the state-of-the-art (SOTA) method by 1.52% in accuracy on average on four open-source datasets. Moreover, subsequent experiments also demonstrate that $DP_2O$ has good universality, robustness, and generalization ability.
format Preprint
id arxiv_https___arxiv_org_abs_2308_07272
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Dialogue for Prompting: a Policy-Gradient-Based Discrete Prompt Generation for Few-shot Learning
Li, Chengzhengxu
Liu, Xiaoming
Wang, Yichen
Li, Duyi
Lan, Yu
Shen, Chao
Machine Learning
Computation and Language
Prompt-based pre-trained language models (PLMs) paradigm have succeeded substantially in few-shot natural language processing (NLP) tasks. However, prior discrete prompt optimization methods require expert knowledge to design the base prompt set and identify high-quality prompts, which is costly, inefficient, and subjective. Meanwhile, existing continuous prompt optimization methods improve the performance by learning the ideal prompts through the gradient information of PLMs, whose high computational cost, and low readability and generalizability are often concerning. To address the research gap, we propose a Dialogue-comprised Policy-gradient-based Discrete Prompt Optimization ($DP_2O$) method. We first design a multi-round dialogue alignment strategy for readability prompt set generation based on GPT-4. Furthermore, we propose an efficient prompt screening metric to identify high-quality prompts with linear complexity. Finally, we construct a reinforcement learning (RL) framework based on policy gradients to match the prompts to inputs optimally. By training a policy network with only 0.67% of the PLM parameter size on the tasks in the few-shot setting, $DP_2O$ outperforms the state-of-the-art (SOTA) method by 1.52% in accuracy on average on four open-source datasets. Moreover, subsequent experiments also demonstrate that $DP_2O$ has good universality, robustness, and generalization ability.
title Dialogue for Prompting: a Policy-Gradient-Based Discrete Prompt Generation for Few-shot Learning
topic Machine Learning
Computation and Language
url https://arxiv.org/abs/2308.07272