Efficient graph neural networks for travelling salesman problem using multilevel clustering

The goal of the Travelling Salesman Problem is to find the shortest route that visits each city exactly once and returns to the origin, given a list of cities and the distances between each pair of cities. Such combinatorial optimization problems are difficult to solve efficiently given large proble...

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Main Author: Dwivedee, Lakshyajeet
Other Authors: Xavier Bresson
Format: Final Year Project (FYP)
Language:English
Published: Nanyang Technological University 2021
Subjects:
Online Access:https://hdl.handle.net/10356/148040
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author Dwivedee, Lakshyajeet
author2 Xavier Bresson
author_facet Xavier Bresson
Dwivedee, Lakshyajeet
author_sort Dwivedee, Lakshyajeet
collection NTU
description The goal of the Travelling Salesman Problem is to find the shortest route that visits each city exactly once and returns to the origin, given a list of cities and the distances between each pair of cities. Such combinatorial optimization problems are difficult to solve efficiently given large problem sizes. Algorithms that solve such problems have applications in many fields such as transportation, operations, and networks. Most solutions formulate heuristics which are policies used by algorithms to search for approximate solutions. These heuristics are designed manually and require specialized knowledge. Graph neural networks have recently been used to automate the creation of these heuristics. However, current state-of-the-art graph neural networks have slow training and inference times due to their O(n2) time complexity. In this paper, we introduce a Multilevel Graph Neural Network (MGNN) for approximating solutions to the TSP by using graph clustering which solves the TSP at multiple resolutions. We train our models on input graph sizes of up to 128 nodes and measure the accuracy as well as experimental time complexity with respect to the graph size. Our divide-and-conquer strategy effectively combats combinatorial explosion by enabling a linear runtime of O(n) at the cost of model accuracy.
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spelling ntu-10356/1480402021-04-22T06:21:59Z Efficient graph neural networks for travelling salesman problem using multilevel clustering Dwivedee, Lakshyajeet Xavier Bresson School of Computer Science and Engineering xbresson@ntu.edu.sg Engineering::Computer science and engineering::Computing methodologies::Artificial intelligence The goal of the Travelling Salesman Problem is to find the shortest route that visits each city exactly once and returns to the origin, given a list of cities and the distances between each pair of cities. Such combinatorial optimization problems are difficult to solve efficiently given large problem sizes. Algorithms that solve such problems have applications in many fields such as transportation, operations, and networks. Most solutions formulate heuristics which are policies used by algorithms to search for approximate solutions. These heuristics are designed manually and require specialized knowledge. Graph neural networks have recently been used to automate the creation of these heuristics. However, current state-of-the-art graph neural networks have slow training and inference times due to their O(n2) time complexity. In this paper, we introduce a Multilevel Graph Neural Network (MGNN) for approximating solutions to the TSP by using graph clustering which solves the TSP at multiple resolutions. We train our models on input graph sizes of up to 128 nodes and measure the accuracy as well as experimental time complexity with respect to the graph size. Our divide-and-conquer strategy effectively combats combinatorial explosion by enabling a linear runtime of O(n) at the cost of model accuracy. Bachelor of Engineering (Computer Engineering) 2021-04-22T06:21:59Z 2021-04-22T06:21:59Z 2021 Final Year Project (FYP) Dwivedee, L. (2021). Efficient graph neural networks for travelling salesman problem using multilevel clustering. Final Year Project (FYP), Nanyang Technological University, Singapore. https://hdl.handle.net/10356/148040 https://hdl.handle.net/10356/148040 en SCSE20-0266 application/pdf Nanyang Technological University
spellingShingle Engineering::Computer science and engineering::Computing methodologies::Artificial intelligence
Dwivedee, Lakshyajeet
Efficient graph neural networks for travelling salesman problem using multilevel clustering
title Efficient graph neural networks for travelling salesman problem using multilevel clustering
title_full Efficient graph neural networks for travelling salesman problem using multilevel clustering
title_fullStr Efficient graph neural networks for travelling salesman problem using multilevel clustering
title_full_unstemmed Efficient graph neural networks for travelling salesman problem using multilevel clustering
title_short Efficient graph neural networks for travelling salesman problem using multilevel clustering
title_sort efficient graph neural networks for travelling salesman problem using multilevel clustering
topic Engineering::Computer science and engineering::Computing methodologies::Artificial intelligence
url https://hdl.handle.net/10356/148040
work_keys_str_mv AT dwivedeelakshyajeet efficientgraphneuralnetworksfortravellingsalesmanproblemusingmultilevelclustering