minizinc

About minizinc

From Debian's package description

MiniZinc is a medium-level constraint modelling language. It is high-level enough to express most constraint problems easily, but low-level enough that it can be mapped onto existing solvers easily and consistently. It is a subset of the higher-level language Zinc.

MiniZinc is designed to interface easily to different backend solvers. It does this by transforming an input MiniZinc model and data file into a FlatZinc model. FlatZinc models consist of variable declaration and constraint definitions as well as a definition of the objective function if the problem is an optimization problem. The translation from MiniZinc to FlatZinc is specializable to individual backend solvers, so they can control what form constraints end up in. In particular, MiniZinc allows the specification of global constraints by decomposition.

From Debian's description of the minizinc package, under that package's license.