Solvers

Solver([globals_dir, support_mzn, …]) Abstract solver class.
Gecode([mzn_path, fzn_path, globals_dir]) Interface to the Gecode solver.
Chuffed([mzn_path, fzn_path, globals_dir]) Interface to the Chuffed solver.
Optimathsat([path, globals_dir]) Interface to the Optimathsat solver.
Opturion([path, globals_dir]) Interface to the Opturion CPX solver.
MIPSolver([path, globals_dir]) Interface to the MIP solver.
Gurobi([path, globals_dir, dll]) Interface to the Gurobi solver.
CBC([path, globals_dir]) Interface to the COIN-OR CBC solver.
G12Solver([mzn_path, fzn_path, globals_dir, …]) Interface to a generic G12 solver.
G12Fd([mzn_path, fzn_path, globals_dir]) Interface to the G12Fd solver.
G12Lazy([mzn_path, fzn_path, globals_dir]) Interface to the G12Lazy solver.
G12MIP([mzn_path, fzn_path, globals_dir]) Interface to the G12MIP solver.
gecode Default Gecode instance.
chuffed Default Chuffed instance.
optimathsat Default Optimathsat instance.
opturion Default Opturion instance.
gurobi Default Gurobi instance.
cbc Default CBC instance.
g12fd Default G12Fd instance.
g12lazy Default G12Lazy instance.
g12mip Default G12Lazy instance.

Provides classes to interface solvers with PyMzn.

PyMzn interfaces with solvers through the Solver base class. This class includes the necessary infomation for PyMzn to setup the solver, together with the solve and solve_start methods, which respectively take care of the running or asynchronously starting a process that solves the MiniZinc/FlatZinc model. PyMzn provides a number of solver implementations out-of-the-box. PyMzn’s default solver is pymzn.gecode, an instance of pymzn.Gecode.

To use a solver that is not provided by PyMzn or to exend an existing one, one has to subclass the Solver class and implement the args method, which returns a list of command line arguments for executing the process. This is generally enough for most solvers, but you can also directly reimplement the solve and solve_start methods for extra flexibility.

For instance:

from pymzn import Solver
from pymzn.process import Process

class MySolver(Solver):
    def __init__(self, path='path/to/solver', globals_dir='path/to/gobals'):
        super().__init__(globals_dir)
        self.cmd = path

    def args(self, fzn_file, *args, arg1=val1, arg2=val2, **kwargs):
        return [self.cmd, '-arg1', arg1, '-arg2', arg2, fzn_file]

Then it is possible to run the minizinc function with the custom solver:

my_solver = MySolver()
pymzn.minizinc('test.mzn', solver=my_solver, arg1=val1, arg2=val2)