MiniZinc Challenge 2015

The Challenge

The aim of the challenge is to start to compare various constraint solving technology on the same problems sets. The focus is on finite domain propagation solvers. An auxiliary aim is to build up a library of interesting problem models, which can be used to compare solvers and solving technologies.

Entrants to the challenge provide a FlatZinc or MiniZinc solver and global constraint definitions specialized for their solver. Each solver is run on 100 MiniZinc model instances. For FlatZinc solvers, we run the translator mzn2fzn on the MiniZinc model and instance using the provided global constraint definitions to create a FlatZinc file. The FlatZinc file is input to the provided FlatZinc solver. For MiniZinc solvers, the MiniZinc model and instance are input to the provided solver. Points are awarded for solving problems, speed of solution, and goodness of solutions (for optimization problems).


  • 2016-05-19 A minor bug in the scoring script was fixed and the results have been updated correspondingly. Thanks to Mohamed Siala for reporting the bug.
  • 2015-09-04 Announcement of the results available here.
  • 2015-08-03 Final submission deadline is now Thu, 6 August 2015.
  • 2015-07-10 Upgrade of MiniZinc distribution to 2.0.4 on the competition VMs. Updated the rules accordingly.
  • 2015-06-24 Announcement of MiniZinc Challenge Judges.
  • 2015-06-24 Official Call for Participation for the MiniZinc Challenge has been made.
  • 2015-04-23 Initial Call for MiniZinc Problems has been made.


  • Registration opens: Wed, 26 June 2015.
  • Problem submission deadline: Fri, 5 June 2015.
  • Initial submission round begins: Sat, 4 July 2015.
  • Initial submission round ends: Sat, 25 July 2015.
  • Final submissions: Sat, 1 August 2015 Thu, 6 August 2015.
  • Announcement of results at CP2015: 31 August - 4 September 2015.


Entrants must register their intention to enter the contest before the first submission round.
The first submission round is an opportunity for us to provide feedback concerning your entry; it does not count towards the final result.
Feel free to register and later withdraw.

To register send an email with the following subject line

    [MZNC15] registration


    mzn-challenge 'at'

In the body of the email please include an email address at which we can contact you.


We will provide submission details via email to the address provided above.

Problem Submission

We strongly encourage all entrants to submit one or two MiniZinc models satisfying the contest requirements, together with instances for these models. They can be submitted as tarballs to:

    mzn-challenge 'at'

The sooner they are submitted the better, the deadline is Fri, 5 June 2015. The call for problem submission is available here. Please feel free to distribute it.


The rules for the MiniZinc Challenge 2015 are available here.
If we need to make changes to the rules, all registered entrants will be informed by email.


The judges will be responsible for selecting the tested instances, vetting the results, and ruling on any questions that arise during the competition.

  • Jimmy H.M. Lee. Chinese University of Hong Kong.
  • Barry O'Sullivan, Cork Constraint Computation Center.
  • Roland Yap, National University of Singapore.


This is the seventh time this challenge is run, and there are many possibilities for comparing CP solvers. The rules try to make a sensible set of choices for the comparison. We would welcome any comments or suggestions regarding the running of this challenge.

We can be contacted with the subject starting with [MZNC15] at:

    mzn-challenge 'at'

MiniZinc forums

The MiniZinc forum is for beginners, users, and developers to discuss MiniZinc. If you would like to join then sign up for the MiniZinc forums.


The MiniZinc page includes a list of resources related to MiniZinc and FlatZinc.

The MiniZinc 2.0 Distribution includes a MiniZinc-to-FlatZinc converter and a large suite of MiniZinc examples and benchmarks.

The MiniZinc Challenge 2014 webpage, include the results from the previous year.

The MiniZinc Challenges 2008-2014 webpage, include the results from each MiniZinc Challenge.