SUNNY-CP 2.2.1
============

SUNNY-CP: a Parallel CP Portfolio Solver

sunny-cp [5] is a parallel parallel portfolio solver that allows to solve a
Constraint (Satisfaction/Optimization) Problem defined in the MiniZinc language.
It essentially implements the SUNNY algorithm described in [1][2][3] and extends
its sequential version [4] that attended the MiniZinc Challenge 2014 [6].
sunny-cp is built on top of state-of-the-art constraint solvers. For the 2019 MiniZinc
competition, it includes:
Choco (parser 4.0.5), picat 26, JaCoP-4.6.0, Yuck 20190601, Or-Tools 7.2 and iZplus.
For the non-eligible version, the following additional solvers are also incorporated:
Gecode and Chuffed.
Normally, the above solvers are not included by default in sunny-cp, 
except for those already included in the MiniZinc bundle
(i.e., G12/LazyFD, G12/FD, and Gecode). However, sunny-cp provides
utilities for adding new solvers to the portfolio and for customizing their
settings.

In a nutshell, sunny-cp relies on two sequential steps:

  1. PRE-SOLVING: consists in the parallel execution of a (maybe empty) static
     schedule and the neighborhood computation of underlying k-NN algorithm;

  2. SOLVING: consists in the parallel and cooperative execution of a number of
     the predicted solvers, selected by means of SUNNY algorithm.

sunny-cp won the gold medal in the open track of MiniZinc Challenges 2015-2017
[6].

This entry submission does not come with a predefined knowledge base
but uses updated solvers compared to the one submitted in 2018. 

 
AUTHORS
=======

sunny-cp is developed by Roberto Amadini (University of Bologna) and Jacopo
Mauro (University of Southern Denmark). For any question or information, please
contact us:

  roberto.amadini at unibo.it 
  mauro at imada.sdu.dk
       

2020 MiniZinc Challenge Participants
=======

Jacopo Mauro
mauro@imada.sdu.dk

Tong Liu
t.liu@unibo.it


REFERENCES
==========

  [1]  R. Amadini, M. Gabbrielli, and J. Mauro. SUNNY: a Lazy Portfolio Approach
       for Constraint Solving 2013. In ICLP, 2014.

  [2]  R. Amadini, M. Gabbrielli, and J. Mauro. Portfolio Approaches for
       Constraint Optimization Problems. In LION, 2014.

  [3]  R. Amadini, and P.J. Stuckey. Sequential Time Splitting and Bounds
       Communication for a Portfolio of Optimization Solvers. In CP, 2014.

  [4]  R. Amadini, M. Gabbrielli, and J. Mauro. SUNNY-CP: a Sequential CP
       Portfolio Solver. In SAC, 2015.

  [5]  R. Amadini, M. Gabbrielli, and J. Mauro. A Multicore Tool for Constraint
       Solving. In IJCAI, 2015.

  [6]  MiniZinc Challenge webpage. http://www.minizinc.org/challenge.html