scholarly journals Solving Integer Linear Programs by Exploiting Variable-Constraint Interactions: A Survey

Algorithms ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 248
Author(s):  
Robert Ganian ◽  
Sebastian Ordyniak

Integer Linear Programming (ILP) is among the most successful and general paradigms for solving computationally intractable optimization problems in computer science. ILP is NP-complete, and until recently we have lacked a systematic study of the complexity of ILP through the lens of variable-constraint interactions. This changed drastically in recent years thanks to a series of results that together lay out a detailed complexity landscape for the problem centered around the structure of graphical representations of instances. The aim of this survey is to summarize these recent developments, put them into context and a unified format, and make them more approachable for experts from many diverse backgrounds.

2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
Kevin K. H. Cheung ◽  
Babak Moazzez

We introduce generalized subadditive generator functions for mixed integer linear programs. Our results extend Klabjan’s work from pure integer programs with nonnegative entries to general MILPs. These functions suffice to achieve strong subadditive duality. Several properties of the functions are shown. We then use this class of functions to generate certificates of optimality for MILPs. We have performed a computational test study on knapsack problems to investigate the efficiency of the certificates.


Author(s):  
Daniel Fišer ◽  
Antonín Komenda

Mutex groups are defined in the context of STRIPS planning as sets of facts out of which, maximally, one can be true in any state reachable from the initial state. This work provides a complexity analysis showing that inference of mutex groups is as hard as planning itself (PSPACE-Complete) and it also shows a tight relationship between mutex groups and graph cliques. Furthermore, we propose a new type of mutex group called a fact-alternating mutex group (fam-group) of which inference is NP-Complete. We introduce an algorithm for the inference of fam-groups based on integer linear programming that is complete with respect to the maximal fam-groups and we demonstrate that fam-groups can be beneficial in the translation of planning tasks into finite domain representation, for the detection of dead-end state and for the pruning of spurious operators. The experimental evaluation of the pruning algorithm shows a substantial increase in a number of solved tasks in domains from the optimal deterministic track of the last two planning competitions (IPC 2011 and 2014).


2020 ◽  
pp. 1082-1099
Author(s):  
Soumaya Fellah ◽  
Mejdi Kaddour

Wireless sensor networks lay down many challenging optimization problems, such as coverage, node deployment, tracking or energy conservation. In this paper, we are interested in deployment strategies that result in a minimum of sensors network while ensuring target coverage connectivity between the sensors and sink. To this end, we propose two alternative deployment approaches based on integer linear programming and we exploit the linear-programming sequential fixing technique to design three polynomial-time heuristic procedures. The performance and effectiveness of these approaches in terms of network cost and computational requirements are highlighted through several experiments. Furthermore, we investigate the network lifetime problem where a given operational duration must be reached.


Author(s):  
Soumaya Fellah ◽  
Mejdi Kaddour

Wireless sensor networks lay down many challenging optimization problems, such as coverage, node deployment, tracking or energy conservation. In this paper, we are interested in deployment strategies that result in a minimum of sensors network while ensuring target coverage connectivity between the sensors and sink. To this end, we propose two alternative deployment approaches based on integer linear programming and we exploit the linear-programming sequential fixing technique to design three polynomial-time heuristic procedures. The performance and effectiveness of these approaches in terms of network cost and computational requirements are highlighted through several experiments. Furthermore, we investigate the network lifetime problem where a given operational duration must be reached.


Author(s):  
Hans L. Bodlaender ◽  
Marieke van der Wegen ◽  
Tom C. van der Zanden

AbstractDivisorial gonality and stable divisorial gonality are graph parameters, which have an origin in algebraic geometry. Divisorial gonality of a connected graph G can be defined with help of a chip firing game on G. The stable divisorial gonality of G is the minimum divisorial gonality over all subdivisions of edges of G. In this paper we prove that deciding whether a given connected graph has stable divisorial gonality at most a given integer k belongs to the class NP. Combined with the result that (stable) divisorial gonality is NP-hard by Gijswijt et al., we obtain that stable divisorial gonality is NP-complete. The proof consists of a partial certificate that can be verified by solving an Integer Linear Programming instance. As a corollary, we have that the total number of subdivisions needed for minimum stable divisorial gonality of a graph with m edges is bounded by mO(mn).


Author(s):  
Лейла Юнси-Аббаси ◽  
Мустафа Мула

В этой статье мы предлагаем новый алгоритм для решения многоцелевых задач стохастического целочисленного линейного программирования (MOSILP). Мы оптимизируем данную стохастическую линейную функцию φ по полному набору эффективных решений MOSILP, которые были преобразованы в эквивалентную детерминированную задачу с использованием неопределенных предположений, вводимых лицом, принимающим решения. Для этой цели мы применяем двухэтапный рекурсивный подход, при котором расширенная взвешенная программа Чебышева постепенно оптимизируется для создания эффективного решения, тем самым улучшая значение вспомогательной функции φ . Предлагаемый здесь подход определяет и решает последовательность целочисленных линейных программ с нарастающими ограничениями, так что на каждом этапе алгоритма генерируется новое эффективное решение. Для иллюстрации представлен числовой пример In this paper, we propose a novel algorithm to deal with multi-objective stochastic integer linear programming problems (MOSILP). Given a stochastic linear function φ , we will optimize it over the full set of efficient solutions of a MOSILP. We convert the latter into an equivalent deterministic problem using uncertain aspirations which are inputs specified by the decision maker. For this purpose, we adopt a 2-stage recourse approach where an augmented weighted Tchebychev program is progressively optimized to generate an efficient solution, the value of the utility function φ is improved to enumerate all efficient solutions. The approach proposed here defines and solves a sequence of progressively more constrained integer linear programs, so that a new efficient solution is generated at each step of the algorithm. A numerical example is presented for illustration


Author(s):  
Pavel Dvořák ◽  
Eduard Eiben ◽  
Robert Ganian ◽  
Dušan Knop ◽  
Sebastian Ordyniak

Integer Linear Programming (ILP) has a broad range of applications in various areas of artificial intelligence. Yet in spite of recent advances, we still lack a thorough understanding of which structural restrictions make ILP tractable. Here we study ILP instances consisting of a small number of ``global'' variables and/or constraints such that the remaining part of the instance consists of small and otherwise independent components; this is captured in terms of a structural measure we call fracture backdoors which generalizes, for instance, the well-studied class of N-fold ILP instances. Our main contributions can be divided into three parts. First, we formally develop fracture backdoors and obtain exact and approximation algorithms for computing these. Second, we exploit these backdoors to develop several new parameterized algorithms for ILP; the performance of these algorithms will naturally scale based on the number of global variables or constraints in the instance. Finally, we complement the developed algorithms with matching lower bounds. Altogether, our results paint a near-complete complexity landscape of ILP with respect to fracture backdoors.


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