MiniZinc Challenge 2008

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 a copy of globals.mzn specialized for their solver. Each solver is run on 100 MiniZinc model(+instance)s. We run the translator mzn2fzn on the MiniZinc model and instance using the provided globals.mzn file 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 shortish for the challenge and in this first instance things may be quite fluid.


  • The results of the MiniZinc Challenge 2008 have been announced.
  • 2008-07-03: the deadline for the first qualification round has been extended to 8 July 2008.
  • 2008-06-25: version 0.8.1 of the G12 MiniZinc distribution has been released. The new version includes a fix for the incorrect definition of the regular constraint inglobals.mzn.
  • 2008-06-16: the challenge rules have been updated to make it clearer what modifications are allowed to be made to globals.mzn by entries.


  • Registration opens: 4 June 2008.
  • First qualification round: 8 July 2008.
  • Problem submission deadline: 18 July 2008.
  • Second qualification round: 25 July 2008.
  • Final submissions: 20 August 2008.
  • Announcement of results at CP2008: 14 September 2008.


Entrants must register their intention to enter the contest before the first qualification round. Feel free to register and later withdraw.

To register send an email with the following subject line

    [MZNC08] registration


    mzn-challenge08 '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 1 or 2 MiniZinc models satisfying the contest requirements, together with instances for these models. They can be submitted as tarballs to

    mzn-challenge08 'at'

The sooner they are submitted the better, the deadline is 18th July 2008.


The rules for the MiniZinc Challenge 2008 are available here. If we need to make changes to the rules, all registered entrants will be informed by email.


  • Jimmy H.M. Lee. Chinese University of Hong Kong.
  • More to be announced


This is the first time this challenge has been run, and there are many possibilities for comparing CP solvers. The rules tries 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-challenge08 'at'

Global constraints library

Version 0.8.1 of the global constraints library is available here.
Version 0.8 of the global constraints library is available here.
(This file is included in the G12 MiniZinc distribution as well.)

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.