Compact Integer Programs for Depot-Free Multiple Traveling Salesperson Problems

Multiple traveling salesperson problems (<i>m</i>TSP) are a collection of problems that generalize the classical traveling salesperson problem (TSP). In a nutshell, an <i>m</i>TSP variant seeks a minimum cost collection of <i>m</i> paths that visit all vertices of...

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Main Authors: José Alejandro Cornejo-Acosta, Jesús García-Díaz, Julio César Pérez-Sansalvador, Carlos Segura
Format: Article
Language:English
Published: MDPI AG 2023-07-01
Series:Mathematics
Subjects:
Online Access:https://www.mdpi.com/2227-7390/11/13/3014
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author José Alejandro Cornejo-Acosta
Jesús García-Díaz
Julio César Pérez-Sansalvador
Carlos Segura
author_facet José Alejandro Cornejo-Acosta
Jesús García-Díaz
Julio César Pérez-Sansalvador
Carlos Segura
author_sort José Alejandro Cornejo-Acosta
collection DOAJ
description Multiple traveling salesperson problems (<i>m</i>TSP) are a collection of problems that generalize the classical traveling salesperson problem (TSP). In a nutshell, an <i>m</i>TSP variant seeks a minimum cost collection of <i>m</i> paths that visit all vertices of a given weighted complete graph. This paper introduces novel compact integer programs for the depot-free <i>m</i>TSP (DF<i>m</i>TSP). This fundamental variant models real scenarios where depots are unknown or unnecessary. The proposed integer programs are adapted to the main variants of the DF<i>m</i>TSP, such as closed paths, open paths, bounding constraints (also known as load balance), and the minsum and minmax objective functions. Some of these integer programs have <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="script">O</mi><mo>(</mo><msup><mi>n</mi><mn>2</mn></msup><mi>m</mi><mo>)</mo></mrow></semantics></math></inline-formula> binary variables and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="script">O</mi><mo>(</mo><msup><mi>n</mi><mn>2</mn></msup><mo>)</mo></mrow></semantics></math></inline-formula> constraints, where <i>m</i> is the number of salespersons and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>n</mi><mo>=</mo><mo>|</mo><mi>V</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>|</mo></mrow></semantics></math></inline-formula>. Furthermore, we introduce more compact integer programs with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="script">O</mi><mo>(</mo><msup><mi>n</mi><mn>2</mn></msup><mo>)</mo></mrow></semantics></math></inline-formula> binary variables and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="script">O</mi><mo>(</mo><msup><mi>n</mi><mn>2</mn></msup><mo>)</mo></mrow></semantics></math></inline-formula> constraints for the same problem and most of its main variants. Without losing their compactness, all the proposed programs are adapted to fixed-destination multiple-depots <i>m</i>TSP (FD-M<i>m</i>TSP) and a combination of FD-M<i>m</i>TSP and DF<i>m</i>TSP, where fewer than <i>m</i> depots are part of the input, but the solution still consists of <i>m</i> paths. We used off-the-shelf optimization software to empirically test the proposed integer programs over a classical benchmark dataset; these tests show that the proposed programs meet desirable theoretical properties and have practical advantages over the state of the art.
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spelling doaj.art-fd4975372b104bb68fb04a0928748e242023-11-18T17:04:35ZengMDPI AGMathematics2227-73902023-07-011113301410.3390/math11133014Compact Integer Programs for Depot-Free Multiple Traveling Salesperson ProblemsJosé Alejandro Cornejo-Acosta0Jesús García-Díaz1Julio César Pérez-Sansalvador2Carlos Segura3Coordinación de Ciencias Computacionales, Instituto Nacional de Astrofísica, Óptica y Electrónica, Puebla 72840, MexicoCoordinación de Ciencias Computacionales, Instituto Nacional de Astrofísica, Óptica y Electrónica, Puebla 72840, MexicoCoordinación de Ciencias Computacionales, Instituto Nacional de Astrofísica, Óptica y Electrónica, Puebla 72840, MexicoÁrea de Computación, Centro de Investigación en Matemáticas, Guanajuato 36240, MexicoMultiple traveling salesperson problems (<i>m</i>TSP) are a collection of problems that generalize the classical traveling salesperson problem (TSP). In a nutshell, an <i>m</i>TSP variant seeks a minimum cost collection of <i>m</i> paths that visit all vertices of a given weighted complete graph. This paper introduces novel compact integer programs for the depot-free <i>m</i>TSP (DF<i>m</i>TSP). This fundamental variant models real scenarios where depots are unknown or unnecessary. The proposed integer programs are adapted to the main variants of the DF<i>m</i>TSP, such as closed paths, open paths, bounding constraints (also known as load balance), and the minsum and minmax objective functions. Some of these integer programs have <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="script">O</mi><mo>(</mo><msup><mi>n</mi><mn>2</mn></msup><mi>m</mi><mo>)</mo></mrow></semantics></math></inline-formula> binary variables and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="script">O</mi><mo>(</mo><msup><mi>n</mi><mn>2</mn></msup><mo>)</mo></mrow></semantics></math></inline-formula> constraints, where <i>m</i> is the number of salespersons and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>n</mi><mo>=</mo><mo>|</mo><mi>V</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>|</mo></mrow></semantics></math></inline-formula>. Furthermore, we introduce more compact integer programs with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="script">O</mi><mo>(</mo><msup><mi>n</mi><mn>2</mn></msup><mo>)</mo></mrow></semantics></math></inline-formula> binary variables and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="script">O</mi><mo>(</mo><msup><mi>n</mi><mn>2</mn></msup><mo>)</mo></mrow></semantics></math></inline-formula> constraints for the same problem and most of its main variants. Without losing their compactness, all the proposed programs are adapted to fixed-destination multiple-depots <i>m</i>TSP (FD-M<i>m</i>TSP) and a combination of FD-M<i>m</i>TSP and DF<i>m</i>TSP, where fewer than <i>m</i> depots are part of the input, but the solution still consists of <i>m</i> paths. We used off-the-shelf optimization software to empirically test the proposed integer programs over a classical benchmark dataset; these tests show that the proposed programs meet desirable theoretical properties and have practical advantages over the state of the art.https://www.mdpi.com/2227-7390/11/13/3014integer programmingmultiple traveling salesperson problemdepot-free <i>m</i>TSP
spellingShingle José Alejandro Cornejo-Acosta
Jesús García-Díaz
Julio César Pérez-Sansalvador
Carlos Segura
Compact Integer Programs for Depot-Free Multiple Traveling Salesperson Problems
Mathematics
integer programming
multiple traveling salesperson problem
depot-free <i>m</i>TSP
title Compact Integer Programs for Depot-Free Multiple Traveling Salesperson Problems
title_full Compact Integer Programs for Depot-Free Multiple Traveling Salesperson Problems
title_fullStr Compact Integer Programs for Depot-Free Multiple Traveling Salesperson Problems
title_full_unstemmed Compact Integer Programs for Depot-Free Multiple Traveling Salesperson Problems
title_short Compact Integer Programs for Depot-Free Multiple Traveling Salesperson Problems
title_sort compact integer programs for depot free multiple traveling salesperson problems
topic integer programming
multiple traveling salesperson problem
depot-free <i>m</i>TSP
url https://www.mdpi.com/2227-7390/11/13/3014
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