Query-Dependent Prompt Evaluation and Optimization with Offline Inverse RL

Original Paper: https://arxiv.org/abs/2309.06553

By: Hao Sun, Alihan Hüyük, Mihaela van der Schaar

Abstract:

In this study, we aim to enhance the arithmetic reasoning ability of Large Language Models (LLMs) through zero-shot prompt optimization. We identify a previously overlooked objective of query dependency in such optimization and elucidate two ensuing challenges that impede the successful and economical design of prompt optimization techniques. One primary issue is the absence of an effective method to evaluate prompts during inference when the golden answer is unavailable. Concurrently, learning via interactions with the LLMs to navigate the expansive natural language prompting space proves to be resource-intensive. To address this, we introduce Prompt-OIRL, which harnesses offline inverse reinforcement learning to draw insights from offline prompting demonstration data. Such data exists as by-products when diverse prompts are benchmarked on open-accessible datasets. With Prompt-OIRL, the query-dependent prompt optimization objective is achieved by first learning an offline reward model. This model can evaluate any query-prompt pairs without accessing LLMs. Subsequently, a best-of-N strategy is deployed to recommend the optimal prompt. Our experimental evaluations across various LLM scales and arithmetic reasoning datasets underscore both the efficacy and economic viability of the proposed approach.

Summary Notes

Enhancing LLM Prompt Optimization with Offline Inverse RL

The world of Artificial Intelligence (AI) is constantly evolving, with Large Language Models (LLMs) at the forefront of solving complex computational and linguistic challenges.

Yet, as these models grow, aligning them with human preferences becomes increasingly difficult. A promising area of focus is prompt optimization—fine-tuning prompts to get better responses from LLMs.

This blog explores an innovative approach called Offline Inverse Reinforcement Learning (OIRL) to improve prompt optimization, inspired by recent research from Hao Sun, Alihan Huyuk, and Mihaela van der Schaar.

The Hurdles of Prompt Optimization

Prompt optimization faces two main challenges:

• Measuring Effectiveness: Determining the success of a prompt in real-time is tough, especially when the correct answers aren't immediately evident.
• Cost and Efficiency: Traditional methods are time-consuming and expensive due to the need for online interactions with LLMs.

Towards Query-Specific Prompting

The discussed paper advocates for moving from a general approach to a query-dependent method in prompt optimization. This means customizing prompts for each query to improve accuracy and efficiency.

The Role of Offline Inverse RL in Prompt Optimization

Prompt-OIRL, the method proposed, uses an offline dataset of past prompt evaluations to avoid costly real-time interactions. It includes three steps:

1. Offline Dataset Construction: Gathering historical evaluation data to create a detailed dataset.
2. Reward Modeling: Developing a model that predicts the effectiveness of prompts using this data.
3. Prompt Optimization: Applying the reward model to find the best prompt for new queries.

Evidence of Success

The effectiveness of Prompt-OIRL has been demonstrated in experiments with various LLMs and datasets, particularly in arithmetic reasoning.

It outperforms traditional methods by adapting to the specifics of each query more efficiently.

Conclusion: Revolutionizing LLM Prompt Optimization

Incorporating Offline Inverse RL into LLM prompt optimization marks a significant advancement. It addresses key issues like evaluating effectiveness and reducing costs, leading to more accurate and cost-effective LLM interactions.

The potential applications of this approach extend beyond arithmetic reasoning, offering exciting possibilities for optimizing LLM prompts across various tasks and industries.

Future Directions

The findings open up many opportunities for further research and practical application. Exploring different datasets and tasks, and combining this method with other AI optimization strategies, could enhance the responsiveness of LLMs to human preferences.

Summary

The use of Offline Inverse RL for prompt optimization in LLMs presents a promising avenue for overcoming some of the field's most significant challenges.

This approach is vital for leveraging the full capabilities of LLMs, ensuring they meet our needs with greater efficiency and effectiveness.

For AI Engineers in the enterprise sector, staying updated with such advancements is crucial for leveraging AI's capabilities to maintain a competitive edge in an AI-centric world.