maxhs.org
MaxHS–A fast and robust MaxSAT solverA fast and robust MaxSAT solver. MaxHS is open source. (Oct 24, 2014). MaxHS v2.9 now available. (Feb 10, 2016). Is a fast solver for a variety of optimization problems. Extends the capabilities of SAT and MIP solvers by exploiting both technologies in a hybrid manner. MaxHS solves problems that are out of reach for both SAT solvers and MIP solvers. Represent your optimization problem in propositional logic. MaxSAT can naturally represent a range of optimization problems.
http://www.maxhs.org/