Annealing-Assisted Column Generation for Inequality-Constrained Combinatorial Optimization Problems

Fuente: arXiv
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Main Authors: Kanai, Hiroshi, Yamashita, Masashi, Tanahashi, Kotaro, Tanaka, Shu
Format: Preprint
Published: 2024
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author Kanai, Hiroshi
Yamashita, Masashi
Tanahashi, Kotaro
Tanaka, Shu
author_facet Kanai, Hiroshi
Yamashita, Masashi
Tanahashi, Kotaro
Tanaka, Shu
contents Ising machines are expected to solve combinatorial optimization problems faster than the existing integer programming solvers. These problems, particularly those encountered in practical situations, typically involve inequality constraints. However, owing to the hardware limitations of the current Ising machines, solving combinatorial optimization problems with inequality constraints remains challenging. The Capacitated Vehicle Routing Problem (CVRP) is a typical example of a problem with inequality constraints. The objective function of the CVRP is to minimize the total distance traveled by each vehicle while limiting the total demand of customers served by a single vehicle to the vehicle's capacity. The CVRP is classified as NP-hard and, thus, is commonly solved using heuristic algorithms, such as column generation. Column generation attempts to iteratively generate only the promising routes, as the number of feasible routes increases exponentially. Within this framework, the CVRP is formulated as a set cover problem. The corresponding dual solutions are used to define the pricing subproblem, which is intended to create a new route. By applying Ising machines to this pricing subproblem, the overall computation time can be reduced. This study aims to solve combinatorial optimization problems with inequality constraints using a hybrid algorithm that combines column generation and Ising machines, thereby extending the applications of the latter. We parameterize the difficulty of the inequality constraints and demonstrate that our annealing-assisted column generation can converge to a better lower bound.
format Preprint
id arxiv_https___arxiv_org_abs_2406_01887
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Annealing-Assisted Column Generation for Inequality-Constrained Combinatorial Optimization Problems
Kanai, Hiroshi
Yamashita, Masashi
Tanahashi, Kotaro
Tanaka, Shu
Statistical Mechanics
Optimization and Control
Ising machines are expected to solve combinatorial optimization problems faster than the existing integer programming solvers. These problems, particularly those encountered in practical situations, typically involve inequality constraints. However, owing to the hardware limitations of the current Ising machines, solving combinatorial optimization problems with inequality constraints remains challenging. The Capacitated Vehicle Routing Problem (CVRP) is a typical example of a problem with inequality constraints. The objective function of the CVRP is to minimize the total distance traveled by each vehicle while limiting the total demand of customers served by a single vehicle to the vehicle's capacity. The CVRP is classified as NP-hard and, thus, is commonly solved using heuristic algorithms, such as column generation. Column generation attempts to iteratively generate only the promising routes, as the number of feasible routes increases exponentially. Within this framework, the CVRP is formulated as a set cover problem. The corresponding dual solutions are used to define the pricing subproblem, which is intended to create a new route. By applying Ising machines to this pricing subproblem, the overall computation time can be reduced. This study aims to solve combinatorial optimization problems with inequality constraints using a hybrid algorithm that combines column generation and Ising machines, thereby extending the applications of the latter. We parameterize the difficulty of the inequality constraints and demonstrate that our annealing-assisted column generation can converge to a better lower bound.
title Annealing-Assisted Column Generation for Inequality-Constrained Combinatorial Optimization Problems
topic Statistical Mechanics
Optimization and Control
url https://arxiv.org/abs/2406.01887