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MiniZinc Challenge 2020 Results

CP 2020 presentation slides of the MiniZinc Challenge 2020 will be available here.


The entrants for this year (with their descriptions, when provided):

In addition, the challenge organisers entered the following FlatZinc and MiniZinc implementations:

As per the challenge rules, these entries are not eligible for prizes, but do modify the scoring results.

Furthermore, entries in the FD search category (Gecode, JaCoP, SICStus Prolog) were automatically included in the free search category, while entries in the free search category (Chuffed, OscaR/CBLS and promoted FD entries except Gecode) were automatically included in the parallel search category. Lastly, all entries in the parallel search category and promoted entries into that category were automatically included in the open search category.

The Choco entry submitted by the final deadline had a bug that prevented it from competing in the free and parallel categories. We entered an updated version that was provided after the deadline and fixed those problems, but we treated it the same as the other internal entries: Choco was therefore ineligible to win prizes in the free and parallel categories, but its performance modifies the scoring results.

Summary of Results

The results for the MiniZinc Challenge 2020 are

FixedSICStus PrologJaCoPChoco 4
FreeOR-ToolsPicatSATMistral 2.0
ParallelOR-ToolsPicatSATMistral 2.0
Local SearchYuckOscaR/CBLS

Description of Results

All times are given in milliseconds.

A score of 0.0 indicates a worse answer in quality (worse objective, no proof of optimality, or no answer for satisfaction problems), 1.0 a better solution in quality. When the quality is the same, the 1.0 purse is split with respect to time used.

If a promoted entry does not recognize an option (or states that it is just ignored), times and solutions from the previous category are used for scoring. The suffixes -fd, -free, -par or -open (for the parallel portfolio solver entered) at the end of the solver names indicate which configuration the solvers were run with.

The time limit includes both MiniZinc compilation and solving.

In the Status column:

  • S indicates that a solution was found,
  • C indicates that the search was complete,
  • ERR indicates an incorrect answer or the solver aborted,
  • ERR indicates that flattening aborted (time-out or out-of-memory),
  • UNK indicates that no answer was returned in the time limit.

Download all problems

All problems are available in a zipped tar-ball here.


Select a list of solvers and benchmarks and click on “Compute Results” to score the solvers against each other on the selected benchmarks. The entrants for each of the fd search, free search and parallel search categories can be selected with the corresponding buttons.

Solver selection: Problem selection:

Plot settings:
Note that plotting takes time.
Create plots for each instance
Time axis scale:
Default Linear Log
Plot lines shape:
Steps Lines
Area scoring settings:


Total per problem:

Solver Score Score Incomplete Score Area
Problem Solver Score Score IncompleteScore Area

Individual results:

Problem Instance Solver Status Time Objective Score Score Incomplete Score Area

Objective plots for each instance:

Problem Instance Plot

Score development over time:

Global constraint per model

The following table lists the global constraints used by each model in this year's challenge. In addition, the columns RC and SBC, respectively, indicate whether the model contains redundant or/and symmetry breaking constraints.

ProblemTypeKindRCSBCMiniZinc Globals
code-generatorrealminall_different, cumulative, decreasing, diffn, diffn_nonstrict, maximum, minimum, table, value_precede_chain
gbaccombiminbin_packing_load, global_cardinality_low_up_closed
isrealmincircuit, table
lot-sizingcombiminall_different, at_least, at_most, global_cardinality
p1f-pjscombiminall_different, circuit, inverse, lex_less

The files on this page are for MiniZinc version 2.4.3.