MiniZinc Challenge 2021 Results

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Entrants

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

• Choco 4 (description). A Java FD solver.
• flatzingo (description).
• iZplus (description).
• JaCoP (description). A Java FD solver.
• Mistral-2.0 (description).
• OR-Tools (description).
• OscaR/CBLS (description). A constraint-based local search solver written in Scala.
• PicatSAT (description).
• SICStus Prolog (description). A Prolog development environment with a FD constraint programming module.
• Yuck (description). A local search solver written in Scala.

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

• Chuffed (description). A C++ FD solver using lazy clause generation.
• Geas (description). A C++ lazy clause generation solver with an OCaml FlatZinc frontend.
• Gecode (description). A C++ FD solver.
• MZN/Cbc (description). Translates to MILP, uses Cbc version 2.10.5.
• MZN/CPLEX (description). Translates to MILP, uses IBM ILOG CPLEX Optimizer version 20.10.
• MZN/Gurobi. Translates to MILP, uses Gurobi version 9.1.2.
• sunny-cp^— (description). A variant of sunny-cp only using the 2020 portfolio CPLEX, Gecode, JaCoP, iZplus, OR-Tools, Picat, SICStus Prolog, Yuck.
• sunny-cp (description). A multi-threaded CP portfolio solver using a 2020 portfolio of CP and MIP solvers incl. Chuffed, Gecode.

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

Summary of Results

The results for the MiniZinc Challenge 2021 are

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).
A score of 1.0 indicates 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.

Selection:

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.

Individual results:

Objective plots for each instance:

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.

The files on this page are for MiniZinc version 2.5.5.