Announcement -13th DIMACS Implementation Challenge: Network Flows 2.0

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13th DIMACS Implementation Challenge: Network Flows 2.0

               Date: January 21-22, 2027 (tentative)
               Location: Lehigh University, Bethlehem, PA, USA

          Organizers:
               Andrew V. Goldberg, Lehigh University
               Tamra Carpenter, DIMACS
               Loukas Georgiadis, University of Ioannina
               Giuseppe Italiano, Luiss University
               Daniel Spielman, Yale University
               Clifford Stein, Columbia University
               David P. Williamson, Cornell University

Presented in association with the DIMACS Implementation Challenges<http://dimacs.rutgers.edu/archive/Challenges/>.

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Announcement:

[cid:[email protected]]The First DIMACS Challenge, devoted to network flows, took place in 1990-1991. The Challenge was a big success and started the tradition of DIMACS Challenges. The First Challenge greatly reduced the gap between theory and practice and raised standards for experimental work in the area. During the decades since the Challenge, network flow algorithms evolved, and new applications of network flows emerged. Many original benchmark instances are too easy for the improved implementations. Theoretical progress has been especially impressive, leading to near-linear algorithms for the minimum-cost flow problem and its special cases. Once again, experimental work is falling behind. The need for updated benchmarks and new algorithm implementations motivates the Network Flows 2.0 Challenge.



The Challenge Workshop will take place at the end of January at Lehigh University<https://www2.lehigh.edu/about/bethlehem-lehigh-valley> campus in Bethlehem, PA, USA. The tentative date for the workshop is January 21-22, 2027. This is just before the 2027 SODA and ALENEX conferences<https://www.siam.org/conferences-events/siam-conferences/alenex27/>. These conferences will be in Philadelphia, PA, about 70 miles from Bethlehem.



The goals for the challenge are:



  *   Update benchmarks for network flow problems to account for improved algorithm performance and to include instances from real-life applications.
  *   Motivate implementations and experimental evaluation of new algorithms.
  *   Compare old and new algorithm implementations on improved benchmarks.

Tracks and core benchmarks

  *   Benchmark track: The first track of the Challenge will produce benchmark instances and instance generators. We will provide links to existing benchmarks and encourage the submission of new ones, both real-life and synthetic. Submitted instances will be visible to participants immediately. Instances submitted by April 15, 2026, will be considered for the core benchmark set. The organizers will compile a set of core benchmarks. In addition, we may accept some papers on "interesting" benchmarks and generators, which give new insight into algorithm performance, for presentation in the workshop.
  *   Implementation track: The second track of the challenge will be devoted to new flow algorithm implementations. This track will start at the same time as the first track. The participants can use existing test instances, instances submitted by the benchmark track participants, or produce their own instances (which they can also contribute).
  *   Core benchmarks: All participants of the implementation track will be required to use the core benchmarks for the problem they are working on. Exceptions will be made only if special aspects of an implementation make it unreasonable (e.g., an implementation is aimed at a specific application). The participants are encouraged to use other benchmarks that they find useful. This will also help to identify benchmarks for future research, which will be one of the outcomes of the Challenge.



Important Dates:


            Instance submission for core benchmarks:     April 15, 2026

            Workshop paper submission (tentative):        September 15, 2026
      Acceptance notification:                                 October 15, 2026
      Final paper due:                                              December 15, 2026
      Challenge workshop (tentative):                     January 21- 22, 2027



For further information:

  *   View the attached 13th DIMACS Implementation Challenge: Network Flows 2.0 Flyer
  *   Visit the Challenge website: https://coral.ise.lehigh.edu/flow-challenge-2-0/
  *   Email the organizers: [email protected]<mailto:[email protected]>

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