Learning 2-opt Heuristics for the Traveling Salesman Problem via Deep Reinforcement Learning

Paulo R. de O. da Costa, Jason Rhuggenaath, Yingqian Zhang, Alp Akcay

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review


Recent works using deep learning to solve the Traveling Salesman Problem (TSP) have focused on learning construction heuristics. Such approaches find TSP solutions of good quality but require additional procedures such as beam search and sampling to improve solutions and achieve state-of-the-art performance. However, few studies have focused on improvement heuristics, where a given solution is improved until reaching a near-optimal one. In this work, we propose to learn a local search heuristic based on 2-opt operators via deep reinforcement learning. We propose a policy gradient algorithm to learn a stochastic policy that selects 2-opt operations given a current solution. Moreover, we introduce a policy neural network that leverages a pointing attention mechanism, which unlike previous works, can be easily extended to more general k-opt moves. Our results show that the learned policies can improve even over random initial solutions and approach near-optimal solutions at a faster rate than previous state-of-the-art deep learning methods.
Original languageEnglish
Title of host publicationProceedings of The 12th Asian Conference on Machine Learning
Publication statusPublished - 2020

Publication series

NameProceedings of Machine Learning Research


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