TRIP-PAL: Travel Planning with Guarantees by Combining Large Language Models and Automated Planners
This addresses the issue of unreliable travel planning for users by incrementally enhancing existing methods to ensure constraint satisfaction and optimization.
The paper tackles the problem of generating coherent and constraint-satisfying travel plans by proposing TRIP-PAL, a hybrid method that combines large language models (LLMs) with automated planners, resulting in improved performance over LLM-only approaches in various travel scenarios.
Travel planning is a complex task that involves generating a sequence of actions related to visiting places subject to constraints and maximizing some user satisfaction criteria. Traditional approaches rely on problem formulation in a given formal language, extracting relevant travel information from web sources, and use an adequate problem solver to generate a valid solution. As an alternative, recent Large Language Model (LLM) based approaches directly output plans from user requests using language. Although LLMs possess extensive travel domain knowledge and provide high-level information like points of interest and potential routes, current state-of-the-art models often generate plans that lack coherence, fail to satisfy constraints fully, and do not guarantee the generation of high-quality solutions. We propose TRIP-PAL, a hybrid method that combines the strengths of LLMs and automated planners, where (i) LLMs get and translate travel information and user information into data structures that can be fed into planners; and (ii) automated planners generate travel plans that guarantee constraint satisfaction and optimize for users' utility. Our experiments across various travel scenarios show that TRIP-PAL outperforms an LLM when generating travel plans.