#include <cp_model_lns.h>

Inheritance diagram for operations_research::sat::RelaxationInducedNeighborhoodGenerator:

Public Member Functions
	RelaxationInducedNeighborhoodGenerator (NeighborhoodGeneratorHelper const helper, const SharedResponseManager response_manager, const SharedLPSolutionRepository lp_solutions, SharedIncompleteSolutionManager incomplete_solutions, absl::string_view name)

Neighborhood	Generate (const CpSolverResponse &initial_solution, SolveData &data, absl::BitGenRef random) final
	Both initial solution and difficulty values are ignored.

bool	ReadyToGenerate () const override
	Returns true if the required solutions are available.

Public Member Functions inherited from operations_research::sat::NeighborhoodGenerator
	NeighborhoodGenerator (absl::string_view name, NeighborhoodGeneratorHelper const *helper)

virtual	~NeighborhoodGenerator ()=default

double	GetUCBScore (int64_t total_num_calls) const

void	AddSolveData (SolveData data)

double	Synchronize ()

std::string	name () const
	Returns a short description of the generator.

int64_t	num_calls () const
	Number of times this generator was called.

int64_t	num_fully_solved_calls () const
	Number of time the neighborhood was fully solved (OPTIMAL/INFEASIBLE).

int64_t	num_improving_calls () const
	Out of num_calls(), how many improved the given solution.

int64_t	num_consecutive_non_improving_calls () const

double	difficulty () const
	The current difficulty of this generator.

double	deterministic_limit () const
	The current time limit that the sub-solve should use on this generator.

Additional Inherited Members
Public Types inherited from operations_research::sat::NeighborhoodGenerator
using	ActiveRectangle = NeighborhoodGeneratorHelper::ActiveRectangle

Protected Attributes inherited from operations_research::sat::NeighborhoodGenerator
const std::string	name_

const NeighborhoodGeneratorHelper &	helper_

absl::Mutex	generator_mutex_

double	deterministic_limit_ = 0.1

Detailed Description

Generates a neighborhood by fixing the variables to solutions reported in various repositories. This is inspired from RINS published in "Exploring relaxation induced neighborhoods to improve MIP solutions" 2004 by E. Danna et.

If incomplete_solutions is provided, this generates a neighborhood by fixing the variable values to a solution in the SharedIncompleteSolutionManager and ignores the other repositories.

Otherwise, if response_manager is not provided, this generates a neighborhood using only the linear/general relaxation values. The domain of the variables are reduced to the integer values around their lp solution/relaxation solution values. This was published in "RENS – The Relaxation Enforced Neighborhood" 2009 by Timo Berthold.

Definition at line 854 of file cp_model_lns.h.

Constructor & Destructor Documentation

◆ RelaxationInducedNeighborhoodGenerator()

operations_research::sat::RelaxationInducedNeighborhoodGenerator::RelaxationInducedNeighborhoodGenerator	(	NeighborhoodGeneratorHelper const *	helper,
		const SharedResponseManager *	response_manager,
		const SharedLPSolutionRepository *	lp_solutions,
		SharedIncompleteSolutionManager *	incomplete_solutions,
		absl::string_view	name )

inlineexplicit

Definition at line 856 of file cp_model_lns.h.

Member Function Documentation

◆ Generate()

Neighborhood operations_research::sat::RelaxationInducedNeighborhoodGenerator::Generate	(	const CpSolverResponse &	initial_solution,
		SolveData &	data,
		absl::BitGenRef	random )

finalvirtual

Both initial solution and difficulty values are ignored.

Fix the variables in the local model.

Todo: (user): Instead of aborting, pick the closest point in the domain?

Implements operations_research::sat::NeighborhoodGenerator.

Definition at line 2759 of file cp_model_lns.cc.

◆ ReadyToGenerate()

bool operations_research::sat::RelaxationInducedNeighborhoodGenerator::ReadyToGenerate ( ) const

overridevirtual

Returns true if the required solutions are available.

Reimplemented from operations_research::sat::NeighborhoodGenerator.

Definition at line 2754 of file cp_model_lns.cc.

The documentation for this class was generated from the following files:

ortools/sat/cp_model_lns.h
ortools/sat/cp_model_lns.cc