def set_up_mip_solver(solve_data, config, regularization_problem):
"""Set up the MIP solver.
Args:
solve_data (MindtPySolveData): data container that holds solve-instance data.
config (ConfigBlock): the specific configurations for MindtPy.
regularization_problem (bool): whether it is solving a regularization problem.
Returns:
mainopt (SolverFactory): the customized MIP solver.
"""
# Deactivate extraneous IMPORT/EXPORT suffixes
if config.nlp_solver == 'ipopt':
getattr(solve_data.mip, 'ipopt_zL_out', _DoNothing()).deactivate()
getattr(solve_data.mip, 'ipopt_zU_out', _DoNothing()).deactivate()
if regularization_problem:
mainopt = SolverFactory(config.mip_regularization_solver)
else:
if config.mip_solver == 'gurobi_persistent' and config.single_tree:
mainopt = GurobiPersistent4MindtPy()
mainopt.solve_data = solve_data
mainopt.config = config
else:
mainopt = SolverFactory(config.mip_solver)
# determine if persistent solver is called.
if isinstance(mainopt, PersistentSolver):
mainopt.set_instance(solve_data.mip, symbolic_solver_labels=True)
if config.single_tree and not regularization_problem:
# Configuration of cplex lazy callback
if config.mip_solver == 'cplex_persistent':
lazyoa = mainopt._solver_model.register_callback(
single_tree.LazyOACallback_cplex)
# pass necessary data and parameters to lazyoa
lazyoa.main_mip = solve_data.mip
lazyoa.solve_data = solve_data
lazyoa.config = config
lazyoa.opt = mainopt
mainopt._solver_model.set_warning_stream(None)
mainopt._solver_model.set_log_stream(None)
mainopt._solver_model.set_error_stream(None)
if config.mip_solver == 'gurobi_persistent':
mainopt.set_callback(single_tree.LazyOACallback_gurobi)
if config.use_tabu_list:
tabulist = mainopt._solver_model.register_callback(
tabu_list.IncumbentCallback_cplex)
tabulist.solve_data = solve_data
tabulist.opt = mainopt
tabulist.config = config
mainopt._solver_model.parameters.preprocessing.reduce.set(1)
# If the callback is used to reject incumbents, the user must set the
# parameter c.parameters.preprocessing.reduce either to the value 1 (one)
# to restrict presolve to primal reductions only or to 0 (zero) to disable all presolve reductions
mainopt._solver_model.set_warning_stream(None)
mainopt._solver_model.set_log_stream(None)
mainopt._solver_model.set_error_stream(None)
return mainopt
