#include <routing_search.h>

Inheritance diagram for operations_research::ChristofidesFilteredHeuristic:

Public Member Functions
	ChristofidesFilteredHeuristic (RoutingModel model, std::function< bool()> stop_search, LocalSearchFilterManager filter_manager, bool use_minimum_matching)
	ChristofidesFilteredHeuristic.

	~ChristofidesFilteredHeuristic () override

bool	BuildSolutionInternal () override

std::string	DebugString () const override

Public Member Functions inherited from operations_research::RoutingFilteredHeuristic
	RoutingFilteredHeuristic (RoutingModel model, std::function< bool()> stop_search, LocalSearchFilterManager filter_manager)
	RoutingFilteredHeuristic.

	~RoutingFilteredHeuristic () override

Assignment *	BuildSolutionFromRoutes (const std::function< int64_t(int64_t)> &next_accessor)
	Builds a solution starting from the routes formed by the next accessor.

RoutingModel *	model () const

int	GetStartChainEnd (int vehicle) const
	Returns the end of the start chain of vehicle,.

int	GetEndChainStart (int vehicle) const
	Returns the start of the end chain of vehicle,.

void	MakeDisjunctionNodesUnperformed (int64_t node)

bool	MakeUnassignedNodesUnperformed ()
	Make all unassigned nodes unperformed, always returns true.

void	MakePartiallyPerformedPairsUnperformed ()

Public Member Functions inherited from operations_research::IntVarFilteredHeuristic
	IntVarFilteredHeuristic (Solver solver, const std::vector< IntVar > &vars, const std::vector< IntVar * > &secondary_vars, LocalSearchFilterManager *filter_manager)
	— First solution heuristics —

virtual	~IntVarFilteredHeuristic ()

Assignment *	BuildSolution ()

int64_t	number_of_decisions () const

int64_t	number_of_rejects () const

Additional Inherited Members
Protected Member Functions inherited from operations_research::RoutingFilteredHeuristic
bool	StopSearch () override
	Returns true if the search must be stopped.

virtual void	SetVehicleIndex (int64_t, int)

virtual void	ResetVehicleIndices ()

bool	VehicleIsEmpty (int vehicle) const

void	SetNext (int64_t node, int64_t next, int vehicle)

Protected Member Functions inherited from operations_research::IntVarFilteredHeuristic
void	ResetSolution ()
	Resets the data members for a new solution.

virtual void	Initialize ()
	Initialize the heuristic; called before starting to build a new solution.

std::optional< int64_t >	Evaluate (bool commit)

void	SetValue (int64_t index, int64_t value)

const std::vector< int > &	delta_indices () const
	Returns the indices of the nodes currently in the insertion delta.

int64_t	Value (int64_t index) const

bool	Contains (int64_t index) const
	Returns true if the variable of index 'index' is in the current solution.

IntVar *	Var (int64_t index) const
	Returns the variable of index 'index'.

int64_t	SecondaryVarIndex (int64_t index) const
	Returns the index of a secondary var.

bool	HasSecondaryVars () const
	Returns true if there are secondary variables.

bool	IsSecondaryVar (int64_t index) const
	Returns true if 'index' is a secondary variable index.

void	SynchronizeFilters ()
	Synchronizes filters with an assignment (the current solution).

Protected Attributes inherited from operations_research::IntVarFilteredHeuristic
Assignment *const	assignment_

Detailed Description

Christofides addition heuristic. Initially created to solve TSPs, extended to support any model by extending routes as much as possible following the path found by the heuristic, before starting a new route.

Definition at line 1413 of file routing_search.h.

Constructor & Destructor Documentation

◆ ChristofidesFilteredHeuristic()

operations_research::ChristofidesFilteredHeuristic::ChristofidesFilteredHeuristic	(	RoutingModel *	model,
		std::function< bool()>	stop_search,
		LocalSearchFilterManager *	filter_manager,
		bool	use_minimum_matching )

ChristofidesFilteredHeuristic.

Definition at line 4075 of file routing_search.cc.

◆ ~ChristofidesFilteredHeuristic()

operations_research::ChristofidesFilteredHeuristic::~ChristofidesFilteredHeuristic ( )

inlineoverride

Definition at line 1419 of file routing_search.h.

Member Function Documentation

◆ BuildSolutionInternal()

bool operations_research::ChristofidesFilteredHeuristic::BuildSolutionInternal ( )

overridevirtual

Todo: (user): Support pickup & delivery.

Node indices for Christofides solver. 0: start/end node >0: non start/end nodes

Todo: (user): Add robustness to fixed arcs by collapsing them into meta- nodes.

To avoid overflow issues, capping costs at kint64max/2, the maximum value supported by MinCostPerfectMatching.

Todo: (user): Investigate if ChristofidesPathSolver should not return a status to bail out fast in case of problem.

Todo: (user): Investigate if sorting paths per cost improves solutions.

Extend route from start.

Implements operations_research::IntVarFilteredHeuristic.

Definition at line 4082 of file routing_search.cc.

◆ DebugString()

std::string operations_research::ChristofidesFilteredHeuristic::DebugString ( ) const

inlineoverridevirtual

Reimplemented from operations_research::IntVarFilteredHeuristic.

Definition at line 1421 of file routing_search.h.

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

ortools/constraint_solver/routing_search.h
ortools/constraint_solver/routing_search.cc

Public Member Functions