SUNNY-CP 2.2
============

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, including:
Choco, Chuffed, CPX, G12/LazyFD, G12/FD, G12/Gurobi, G12/CBC, Gecode, HaifaCSP,
JaCoP, iZplus, MinisatID, Mistral, Opturion, OR-Tools, Picat. These solvers are 
not included by default in sunny-cp, except for those already included in the 
MiniZinc bundle (i.e., G12/CBC, G12/LazyFD, G12/FD, and Gecode).
However, sunny-cp provides utilities for adding new solvers to the portfolio and
for customizing their settings (see below).

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 2015/6 [6].


AUTHORS
=======

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

  roberto.amadini at unimelb.edu.au

          jmauro  at ifi.uio.no
       
  
ACKNOWLEDGMENTS
===============

We would like to thank the staff of the Optimization Research Group of NICTA
(National ICT of Australia) for allowing us to use G12/Gurobi, as well as for
granting us the computational resources needed for building and testing sunny-cp.


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