Gioni Mexi

researcher at ZIB since August 2021
doctoral candidate at TUB

📬 Contact

office Room 3101 at ZIB
e-mail mexi (at) zib.de

🎓 Academic Background

Jul 2021 M.Sc. at TUB
Mar 2019 B.Sc. in Mathematics at TUB

🔬 Research

My research interests include primal heuristics, generalization of conflict analysis techniques in mixed-integer programming, and the integration of different solver technologies.

Preprints

  1. Bolusani, S., Besançon, M., Bestuzheva, K., Chmiela, A., Dionísio, J., Donkiewicz, T., van Doornmalen, J., Eifler, L., Ghannam, M., Gleixner, A., Graczyk, C., Halbig, K., Hedtke, I., Hoen, A., Hojny, C., van der Hulst, R., Kamp, D., Koch, T., Kofler, K., … Xu, L. (2024). The SCIP Optimization Suite 9.0 (ZIB Report No. 24-02-29). Zuse Institute Berlin. [URL] [arXiv] [code]
    [BibTeX]
    @techreport{BolusaniEtal2024,
      year = {2024},
      institution = {Zuse Institute Berlin},
      type = {ZIB Report},
      month = feb,
      number = {24-02-29},
      url = {https://nbn-resolving.org/urn:nbn:de:0297-zib-95528},
      archiveprefix = {arXiv},
      eprint = {2402.17702},
      primaryclass = {math.OC},
      author = {Bolusani, Suresh and Besançon, Mathieu and Bestuzheva, Ksenia and Chmiela, Antonia and Dionísio, João and Donkiewicz, Tim and van Doornmalen, Jasper and Eifler, Leon and Ghannam, Mohammed and Gleixner, Ambros and Graczyk, Christoph and Halbig, Katrin and Hedtke, Ivo and Hoen, Alexander and Hojny, Christopher and van der Hulst, Rolf and Kamp, Dominik and Koch, Thorsten and Kofler, Kevin and Lentz, Jurgen and Manns, Julian and Mexi, Gioni and Mühmer, Erik and Pfetsch, Marc and Schlösser, Franziska and Serrano, Felipe and Shinano, Yuji and Turner, Mark and Vigerske, Stefan and Weninger, Dieter and Xu, Liding},
      title = {The SCIP Optimization Suite 9.0},
      code = {https://scipopt.org}
    }

Conference proceedings

  1. Ghannam, M., Mexi, G., Lam, E., and Gleixner, A. (2024). Branch and Price for the Length-constrained Cycle Partition Problem. Proceedings of INFORMS Optimization Society Conference. [URL] [arXiv]
    [BibTeX]
    @inproceedings{GhannamMexiLamGleixner2024,
      year = {2024},
      booktitle = {Proceedings of INFORMS Optimization Society Conference},
      url = {https://sites.google.com/view/ios2024refereed},
      archiveprefix = {arXiv},
      eprint = {2401.17937},
      primaryclass = {math.OC},
      author = {Ghannam, Mohammed and Mexi, Gioni and Lam, Edward and Gleixner, Ambros},
      title = {Branch and Price for the Length-constrained Cycle Partition Problem}
    }
  2. Mexi, G., Shamsi, S., Besançon, M., and le Bodic, P. (2024). Probabilistic Lookahead Strong Branching Via a Stochastic Abstract Branching Model. Proceedings of International Conference on the Integration of Constraint Programming, Artificial Intelligence, and Operations Research. [arXiv]
    [BibTeX]
    @inproceedings{probabilistic_lookahead_23,
      year = {2024},
      booktitle = {Proceedings of International Conference on the Integration of Constraint Programming, Artificial Intelligence, and Operations Research},
      archiveprefix = {arXiv},
      eprint = {2312.07041},
      primaryclass = {math.OC},
      author = {Mexi, Gioni and Shamsi, Somayeh and Besançon, Mathieu and le Bodic, Pierre},
      title = {Probabilistic Lookahead Strong Branching Via a Stochastic Abstract Branching Model}
    }
  3. Mexi, G., Berthold, T., Gleixner, A., and Nordström, J. (2023). Improving Conflict Analysis in MIP Solvers by Pseudo-Boolean Reasoning. Proceedings of 29th International Conference on Principles and Practice of Constraint Programming (CP 2023), 280, 27:1–27:19, DOI: 10.4230/LIPIcs.CP.2023.27
    [BibTeX]
    @inproceedings{mexi2023improving,
      year = {2023},
      booktitle = {Proceedings of 29th International Conference on Principles and Practice of Constraint Programming (CP 2023)},
      volume = {280},
      pages = {27:1-27:19,},
      doi = {10.4230/LIPIcs.CP.2023.27},
      author = {Mexi, Gioni and Berthold, Timo and Gleixner, Ambros and Nordström, Jakob},
      title = {Improving Conflict Analysis in MIP Solvers by Pseudo-Boolean Reasoning}
    }
  4. Mexi, G., Besançon, M., Bolusani, S., Chmiela, A., Hoen, A., and Gleixner, A. (2023). Scylla: a Matrix-free Fix-propagate-and-project Heuristic for Mixed-integer Optimization. Proceedings of Conference of the Society for Operations Research in Germany. [arXiv]
    [BibTeX]
    @inproceedings{scyllaheuristic,
      year = {2023},
      booktitle = {Proceedings of Conference of the Society for Operations Research in Germany},
      archiveprefix = {arXiv},
      eprint = {2307.03466},
      primaryclass = {math.OC},
      author = {Mexi, Gioni and Besançon, Mathieu and Bolusani, Suresh and Chmiela, Antonia and Hoen, Alexander and Gleixner, Ambros},
      title = {Scylla: a Matrix-free Fix-propagate-and-project Heuristic for Mixed-integer Optimization}
    }
  5. Hoppmann-Baum, K., Mexi, G., Burdakov, O., Casselgren, C. J., and Koch, T. (2020). Minimum Cycle Partition with Length Requirements. Proceedings of International Conference on the Integration of Constraint Programming, Artificial Intelligence, and Operations Research, 12296, 273–282. DOI: 10.1007/978-3-030-58942-4_18
    [BibTeX]
    @inproceedings{HoppmannBaumMexiBurdakovetal.2020,
      year = {2020},
      booktitle = {Proceedings of International Conference on the Integration of Constraint Programming, Artificial Intelligence, and Operations Research},
      volume = {12296},
      pages = {273-282},
      doi = {10.1007/978-3-030-58942-4_18},
      author = {Hoppmann-Baum, Kai and Mexi, Gioni and Burdakov, Oleg and Casselgren, Carl Johan and Koch, Thorsten},
      title = {Minimum Cycle Partition with Length Requirements}
    }

Full articles

  1. Berthold, T., Mexi, G., and Salvagnin, D. (2023). Using Multiple Reference Vectors and Objective Scaling in the Feasibility Pump. EURO Journal on Computational Optimization, 11. DOI: 10.1016/j.ejco.2023.100066
    [BibTeX]
    @article{BertholdMexiSalvagnin2023,
      year = {2023},
      journal = {EURO Journal on Computational Optimization},
      volume = {11},
      doi = {10.1016/j.ejco.2023.100066},
      author = {Berthold, Timo and Mexi, Gioni and Salvagnin, Domenico},
      title = {Using Multiple Reference Vectors and Objective Scaling in the Feasibility Pump}
    }
  2. Hoppmann-Baum, K., Burdakov, O., Mexi, G., Casselgren, C. J., and Koch, T. (2022). Length-Constrained Cycle Partition with an Application to UAV Routing. Optimization Methods and Software. DOI: 10.1080/10556788.2022.2053972
    [BibTeX]
    @article{HoppmannBaumBurdakovMexietal.2022,
      year = {2022},
      journal = {Optimization Methods and Software},
      doi = {10.1080/10556788.2022.2053972},
      author = {Hoppmann-Baum, Kai and Burdakov, Oleg and Mexi, Gioni and Casselgren, Carl Johan and Koch, Thorsten},
      title = {Length-Constrained Cycle Partition with an Application to UAV Routing}
    }

💬 Talks and posters

Conference and workshop talks

Sep 2023
SAP-ZIB-FAU Workshop, Walldorf
Aug 2023
29th CP Conference, Toronto [PDF]
Jul 2023
14th Pragmatics of SAT International Workshop, Alghero [PDF]
Jan 2023
SAP-ZIB-FAU Workshop, Walldorf