MiniZinc Challenge 2009

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 solver and global constraint definitions specialized for their solver. Each solver is run on 100 MiniZinc model instances. 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 solver. Points are awarded for solving problems, speed of solution, and goodness of solutions (for optimization problems).

We realise the time lines are quite short for the challenge.


  • 2009-09-21 The results of the 2009 MiniZinc challenge are available here.
  • 2009-08-10 Information about entry submission has been mailed to registered entrants.
    We will accept entries for the initial submission round up to the 20 August 2009.
  • 2009-06-04 A gzipped tarball containing MiniZinc 1.0 versions of the 2008 MiniZinc challenge problems is available here.
    Last year's problems are also available in the benchmarks directory of the MiniZinc distribution.


  • Registration opens: 1 June 2009.
  • Problem submission deadline: 31 July 2009.
  • Initial submission round begins: 10 August 2009.
  • Initial submission round ends: 20 August 2009.
  • Final submissions: 30 August 2009.
  • Announcement of results at CP2009: 20 September 2009.


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

    [MZNC09] 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 31 July 2009.


The rules for the MiniZinc Challenge 2009 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 second 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 at:

    mzn-challenge 'at'

Mailing list

The G12 users mailing list is intended for general discussion of MiniZinc and FlatZinc.
If you would like to join then send a mail with subscribe in the body to:

	g12-users-request 'at'

After subscribing you can then send mail to:

	g12-users 'at'


The G12 MiniZinc page includes a list of resources related to MiniZinc and FlatZinc.

The G12 MiniZinc Distribution includes a MiniZinc-to-FlatZinc converter and a large suite of MiniZinc examples and benchmarks.

The MiniZinc Challenge 2008 webpage, including the results from last year.