Improving Conflict Analysis in MIP Solvers by Pseudo-Boolean Reasoning

Publikation: Bidrag til bog/antologi/rapportKonferencebidrag i proceedingsForskningfagfællebedømt

Dokumenter

  • Fulltext

    Forlagets udgivne version, 821 KB, PDF-dokument

Conflict analysis has been successfully generalized from Boolean satisfiability (SAT) solving to mixed integer programming (MIP) solvers, but although MIP solvers operate with general linear inequalities, the conflict analysis in MIP has been limited to reasoning with the more restricted class of clausal constraint. This is in contrast to how conflict analysis is performed in so-called pseudo-Boolean solving, where solvers can reason directly with 0-1 integer linear inequalities rather than with clausal constraints extracted from such inequalities. In this work, we investigate how pseudo-Boolean conflict analysis can be integrated in MIP solving, focusing on 0-1 integer linear programs (0-1 ILPs). Phrased in MIP terminology, conflict analysis can be understood as a sequence of linear combinations and cuts. We leverage this perspective to design a new conflict analysis algorithm based on mixed integer rounding (MIR) cuts, which theoretically dominates the state-of-the-art division-based method in pseudo-Boolean solving. We also report results from a first proof-of-concept implementation of different pseudo-Boolean conflict analysis methods in the open-source MIP solver SCIP. When evaluated on a large and diverse set of 0-1 ILP instances from MIPLIB 2017, our new MIR-based conflict analysis outperforms both previous pseudo-Boolean methods and the clause-based method used in MIP. Our conclusion is that pseudo-Boolean conflict analysis in MIP is a promising research direction that merits further study, and that it might also make sense to investigate the use of such conflict analysis to generate stronger no-goods in constraint programming.

OriginalsprogEngelsk
Titel29th International Conference on Principles and Practice of Constraint Programming, CP 2023
RedaktørerRoland H. C. Yap Yap
Antal sider19
ForlagSchloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing
Publikationsdato2023
Artikelnummer27
ISBN (Elektronisk)9783959773003
DOI
StatusUdgivet - 2023
Begivenhed29th International Conference on Principles and Practice of Constraint Programming, CP 2023 - Toronto, Canada
Varighed: 27 aug. 202331 aug. 2023

Konference

Konference29th International Conference on Principles and Practice of Constraint Programming, CP 2023
LandCanada
ByToronto
Periode27/08/202331/08/2023
SponsorAssociation for Constraint Programming (ACP), Cosling, Department of Management, University of Toronto Scarborough, et al., Google, The Artificial Intelligence Journal (Elsevier)
NavnLeibniz International Proceedings in Informatics, LIPIcs
Vol/bind280
ISSN1868-8969

Bibliografisk note

Funding Information:
Funding The work for this article has been conducted within the Research Campus Modal funded by the German Federal Ministry of Education and Research (BMBF grant numbers 05M14ZAM, 05M20ZBM). Jakob Nordström: supported by the Swedish Research Council grant 2016-00782 and the Independent Research Fund Denmark grant 9040-00389B.

Publisher Copyright:
© Gioni Mexi, Timo Berthold, Ambros Gleixner, and Jakob Nordström.

ID: 390858432