Branch and Cut Algorithms

The Largest Unsolved QAP Instance Tai256c Can Be Converted into A 256-dimensional Simple BQOP with A Single Cardinality Constraint

  • Koichi Fujii
  • Sunyoung Kim
  • Masakazu Kojima
  • Hans D Mittelmann
  • Yuji Shinano
    • Categories 0-1 Programming, Branch and Cut Algorithms, Semi-definite Programming Tags , , , , ,

    Tai256c is the largest unsolved quadratic assignment problem (QAP) instance in QAPLIB; a 1.48\% gap remains between the best known feasible objective value and lower bound of the unknown optimal value. This paper shows that the instance can be converted into a 256 dimensional binary quadratic optimization problem (BQOP) with a single cardinality constraint which … Read more

    Cutting-plane algorithm for sparse estimation of the Cox proportional-hazards model

  • Hiroki Saishu
  • Kota Kudo
  • Yuichi Takano
    • Categories (Mixed) Integer Nonlinear Programming, Branch and Cut Algorithms, Statistics Tags , , , , ,

    Survival analysis is a family of statistical methods for analyzing event occurrence times. In this paper, we address the mixed-integer optimization approach to sparse estimation of the Cox proportional-hazards model for survival analysis. Specifically, we propose a high-performance cutting-plane algorithm based on reformulation of bilevel optimization for sparse estimation. This algorithm solves the upper-level problem … Read more

    On optimally solving sub-tree scheduling for wireless sensor networks with partial coverage

  • Nicola Bianchessi
    • Categories Branch and Cut Algorithms, Network Optimization, Telecommunications Tags , , , , ,

    Energy efficiency and balancing are very important issues from the perspective of increasing the lifetime of a wireless sensor network (WSN). In this study, we concentrate on energy balancing. Given a WSN, we consider the problem to minimize its total power consumption over consecutive time slots with respect to communication activities. Disjoint subsets of nodes … Read more

    Benders-type Branch-and-Cut Algorithms for Capacitated Facility Location with Single-Sourcing

  • Dieter Weninger
  • Laurence A. Wolsey
    • Categories (Mixed) Integer Linear Programming, Branch and Cut Algorithms, Facility Planning and Design Tags , , , ,

    We consider the capacitated facility location problem with (partial) single-sourcing (CFLP-SS). A natural mixed integer formulation for the problem involves 0-1 variables x_j indicating whether faclility j is used or not and y_{ij} variables indicating the fraction of the demand of client i that is satisfied from facility j. When the x variables are fixed, … Read more

    On the Complexity of Finding Shortest Variable Disjunction Branch-and-Bound Proofs

  • Max Gläser
  • Marc E. Pfetsch
    • Categories Branch and Cut Algorithms Tags , ,

    We investigate the complexity of finding small branch-and-bound trees using variable disjunctions. We first show that it is not possible to approximate the size of a smallest branch-and-bound tree within a factor of 2^(1/5) in time 2^(\delta n) with \delta < 1/5, unless the strong exponential time hypothesis fails. Similarly, for any \varepsilon > 0, … Read more

    Branch-and-Bound Performance Estimation Programming: A Unified Methodology for Constructing Optimal Optimization Methods

  • Shuvomoy Das Gupta
  • Bart Paul Gerard Van Parys
  • Ernest K. Ryu
    • Categories Branch and Cut Algorithms, Nonlinear Optimization, Quadratic Programming Tags , ,

    We present the Branch-and-Bound Performance Estimation Programming (BnB-PEP), a unified methodology for constructing optimal first-order methods for convex and nonconvex optimization. BnB-PEP poses the problem of finding the optimal optimization method as a nonconvex but practically tractable quadratically constrained quadratic optimization problem and solves it to certifiable global optimality using a customized branch-and-bound algorithm. By … Read more

    Heuristic approaches for split delivery vehicle routing problems

  • Aldair Álvarez
  • Pedro Munari
    • Categories Branch and Cut Algorithms, Meta Heuristics, Transportation Tags , , , ,

    We propose a matheuristic approach to solve split delivery variants of the vehicle routing problem (VRP). The proposed method is based on the use of several mathematical programming components within an Iterated Local Search metaheuristic framework. In addition to well-known VRP local search heuristics, we include new types of improvement and perturbation strategies that are … Read more

    Models and Algorithms for the Weighted Safe Set Problem

  • Enrico Malaguti
  • Vagner Pedrotti
    • Categories Branch and Cut Algorithms, Graphs and Matroids Tags , , ,

    Given a connected graph G = (V, E), a Safe Set S is a subset of the vertex set V such that the cardinality of each connected component in the subgraph induced by V \ S does not exceed the cardinality of any neighbor connected component in the subgraph induced by S. When the vertices … Read more

    Faster exact solution of sparse MaxCut and QUBO problems

  • Daniel Rehfeldt
  • Thorsten Koch
  • Yuji Shinano
    • Categories Branch and Cut Algorithms Tags

    The maximum-cut problem is one of the fundamental problems in combinatorial optimization. With the advent of quantum computers, both the maximum-cut and the equivalent quadratic unconstrained binary optimization problem have experienced much interest in recent years. This article aims to advance the state of the art in the exact solution of both problems-by using mathematical … Read more