operations_research::sat::ConstraintGraphNeighborhoodGenerator Class Reference

#include <cp_model_lns.h>

Inheritance diagram for operations_research::sat::ConstraintGraphNeighborhoodGenerator:

Public Member Functions
	ConstraintGraphNeighborhoodGenerator (NeighborhoodGeneratorHelper const *helper, absl::string_view name)
Neighborhood	Generate (const CpSolverResponse &initial_solution, double difficulty, absl::BitGenRef random) final
Public Member Functions inherited from operations_research::sat::NeighborhoodGenerator
	NeighborhoodGenerator (absl::string_view name, NeighborhoodGeneratorHelper const *helper)
virtual	~NeighborhoodGenerator ()=default
virtual bool	ReadyToGenerate () const
	Returns true if the neighborhood generator can generate a neighborhood.
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
Protected Attributes inherited from operations_research::sat::NeighborhoodGenerator
const std::string	name_
const NeighborhoodGeneratorHelper &	helper_
absl::Mutex	generator_mutex_

Detailed Description

Pick a random subset of constraint and relax all of their variables. We are a bit smarter than this because after the first constraint is selected, we only select constraints that share at least one variable with the already selected constraints. The variable from the "last" constraint are selected randomly.

Definition at line 559 of file cp_model_lns.h.

Constructor & Destructor Documentation

ConstraintGraphNeighborhoodGenerator()

operations_research::sat::ConstraintGraphNeighborhoodGenerator::ConstraintGraphNeighborhoodGenerator ( NeighborhoodGeneratorHelper const * helper, absl::string_view name )

inlineexplicit

Definition at line 561 of file cp_model_lns.h.

Member Function Documentation

Generate()

Neighborhood operations_research::sat::ConstraintGraphNeighborhoodGenerator::Generate ( const CpSolverResponse & initial_solution, double difficulty, absl::BitGenRef random )

finalvirtual

Note

even if difficulty means full neighborhood, we go through the generation process to never get out of a connected components.

Start by a random constraint.

Stop if we have a full connected component.

Pick a random unprocessed constraint.

Add all the variable of this constraint and increase the set of next possible constraints.

Implements operations_research::sat::NeighborhoodGenerator.

Definition at line 1490 of file cp_model_lns.cc.

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

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