Integer Programming

A Multi-Reference Relaxation Enforced Neighborhood Search Heuristic in SCIP

  • Suresh Bolusani
  • Gioni Mexi
  • Mathieu Besançon
  • Mark Turner
    • Categories (Mixed) Integer Linear Programming, Branch and Cut Algorithms, Optimization Software and Modeling Systems Tags , , ,

    This paper proposes and evaluates a Multi-Reference Relaxation Enforced Neighborhood Search (MRENS) heuristic within the SCIP solver. This study marks the first integration and evaluation of MRENS in a full-fledged MILP solver, specifically coupled with the recently-introduced Lagromory separator for generating multiple reference solutions. Computational experiments on the MIPLIB 2017 benchmark set show that MRENS, … Read more

    Compact Mixed Integer Programming Formulations for the Minimum Biclique Cover Problem

  • Bruno Burin
  • Hamidreza Validi
  • Bochuan Lyu
  • Illya V. Hicks
    • Categories Combinatorial Optimization, Integer Programming, Network Optimization Tags , ,

    Given a simple graph G = (V, E) with vertex set V and edge set E, the minimum biclique cover problem seeks to cover all edges of the graph with a minimum number of bicliques (i.e., complete bipartite subgraphs). This paper proposes two compact mixed integer programming (MIP) formulations for solving the minimum biclique cover … Read more

    Cluster branching for vehicle routing problems

  • Joao Marcos P Silva
  • Eduardo Uchoa
  • Anand Subramanian
    • Categories Applications - OR and Management Sciences, Combinatorial Optimization, Integer Programming Tags , , ,

    This article introduces Cluster Branching, a novel branching strategy for exact algorithms solving Vehicle Routing Problems (VRPs). While branching is crucial for the efficiency of branch-and-bound-based algorithms, existing branching types such as Edge Branching, CutSet Branching, and Ryan&Foster Branching have their limitations. The proposed branching strategy aggregates multiple edge variables into higher-level decision structures corresponding … Read more

    Interdiction of minimum spanning trees and other matroid bases

  • Noah Weninger
  • Ricardo Fukasawa
    • Categories 0-1 Programming, Dynamic Programming, Graphs and Matroids Tags , , , , , ,

    In the minimum spanning tree (MST) interdiction problem, we are given a graph \(G=(V,E)\) with edge weights, and want to find some \(X\subseteq E\) satisfying a knapsack constraint such that the MST weight in \((V,E\setminus X)\) is maximized. Since MSTs of \(G\) are the minimum weight bases in the graphic matroid of \(G\), this problem … Read more

    Integer Programming Approaches for Distributionally Robust Chance Constraints with Adjustable Risks

  • Yiling Zhang
    • Categories Integer Programming, Robust Optimization, Stochastic Programming

    We study distributionally robust chance-constrained programs (DRCCPs) with individual chance constraints under a Wasserstein ambiguity. The DRCCPs treat the risk tolerances associated with the distributionally robust chance constraints (DRCCs) as decision variables to trade off between the system cost and risk of violations by penalizing the risk tolerances in the objective function. The introduction of … Read more

    Computational Methods for the Household Assignment Problem

  • Ulf Friedrich
  • Lucas Moschen
  • Ralf Münnich
  • Martin Schmidt
    • Categories Applications - OR and Management Sciences, Approximation Algorithms, Integer Programming Tags , , , ,

    We consider the problem of assigning the entries of a household data set to real-world address data. This household assignment problem occurs in the geo-referencing step of spatial microsimulation models. The resulting combinatorial optimization model is a maximum weight matching problem with additional side constraints. Even for real-world instances of medium size, such as the … Read more

    Granularity for mixed-integer polynomial optimization problems

  • Carl Eggen
  • Oliver Stein
  • Stefan Volkwein
    • Categories (Mixed) Integer Nonlinear Programming, Semi-definite Programming Tags , , , ,

    Finding good feasible points is crucial in mixed-integer programming. For this purpose we combine a sufficient condition for consistency, called granularity, with the moment-/sos-hierarchy from polynomial optimization. If the mixed-integer problem is granular, we obtain feasible points by solving continuous polynomial problems and rounding their optimal points. The moment-/sos-hierarchy is hereby used to solve those … Read more

    BOBILib: Bilevel Optimization (Benchmark) Instance Library

  • Johannes Thürauf
  • Thomas Kleinert
  • Ivana Ljubić
  • Ted K. Ralphs
  • Martin Schmidt
    • Categories (Mixed) Integer Linear Programming, Bilevel Optimization, Optimization Software Benchmark Tags , , , ,

    In this report, we present the BOBILib, a collection of more than 2600 instances of mixed integer bilevel linear optimization problems (MIBLPs). The goal of this library is to provide a large and well-curated set of test instances freely available for the research community so that new and existing algorithms in bilevel optimization can be … Read more

    Exact Augmented Lagrangian Duality for Nonconvex Mixed-Integer Nonlinear Optimization

  • Henri Lefebvre
  • Martin Schmidt
    • Categories (Mixed) Integer Linear Programming, (Mixed) Integer Nonlinear Programming Tags , ,

    In the context of mixed-integer nonlinear problems (MINLPs), it is well-known that strong duality does not hold in general if the standard Lagrangian dual is used. Hence, we consider the augmented Lagrangian dual (ALD), which adds a nonlinear penalty function to the classic Lagrangian function. For this setup, we study conditions under which the ALD … Read more

    Inverse of the Gomory Corner Relaxation of Integer Programs

  • Fatemeh Nosrat
  • George Lyu
  • Andrew J. Schaefer
    • Categories (Mixed) Integer Linear Programming, Integer Programming, Other Topics Tags , , ,

    We analyze the inverse of the Gomory corner relaxation (GCR) of a pure integer program (IP). We prove the inverse GCR is equivalent to the inverse of a shortest path problem, yielding a polyhedral representation of the GCR inverse-feasible region. We present a linear programming (LP) formulation for solving the inverse GCR under the \(L_{1}\) … Read more