Detailed Description

Definition at line 34 of file knapsack_interface.cc.

Inheritance diagram for operations_research::KnapsackInterface:

Public Member Functions
	KnapsackInterface (MPSolver *solver)
	~KnapsackInterface () override
MPSolver::ResultStatus	Solve (const MPSolverParameters &param) override
	--— Solve --—
void	Reset () override
	--— Model modifications and extraction --—
void	SetOptimizationDirection (bool maximize) override
	Sets the optimization direction (min/max).
void	SetVariableBounds (int index, double lb, double ub) override
	Modifies bounds of an extracted variable.
void	SetVariableInteger (int index, bool integer) override
	Modifies integrality of an extracted variable.
void	SetConstraintBounds (int index, double lb, double ub) override
	Modify bounds of an extracted variable.
void	AddRowConstraint (MPConstraint *ct) override
	Adds a linear constraint.
void	AddVariable (MPVariable *var) override
	Add a variable.
void	SetCoefficient (MPConstraint constraint, const MPVariable variable, double new_value, double old_value) override
	Changes a coefficient in a constraint.
void	ClearConstraint (MPConstraint *constraint) override
	Clears a constraint from all its terms.
void	SetObjectiveCoefficient (const MPVariable *variable, double coefficient) override
	Changes a coefficient in the linear objective.
void	SetObjectiveOffset (double value) override
	Changes the constant term in the linear objective.
void	ClearObjective () override
	Clears the objective from all its terms.
int64_t	iterations () const override
	---— Query statistics on the solution and the solve ---—
int64_t	nodes () const override
MPSolver::BasisStatus	row_status (int constraint_index) const override
	Returns the basis status of a row.
MPSolver::BasisStatus	column_status (int variable_index) const override
	Returns the basis status of a constraint.
bool	IsContinuous () const override
	--— Misc --—
bool	IsLP () const override
	Returns true if the problem is continuous and linear.
bool	IsMIP () const override
	Returns true if the problem is discrete and linear.
std::string	SolverVersion () const override
	Returns a string describing the underlying solver and its version.
void *	underlying_solver () override
	Returns the underlying solver.
void	ExtractNewVariables () override
	Extracts the variables that have not been extracted yet.
void	ExtractNewConstraints () override
	Extracts the constraints that have not been extracted yet.
void	ExtractObjective () override
	Extracts the objective.
void	SetParameters (const MPSolverParameters &param) override
	Sets all parameters in the underlying solver.
void	SetRelativeMipGap (double value) override
	Sets each parameter in the underlying solver.
void	SetPrimalTolerance (double value) override
void	SetDualTolerance (double value) override
void	SetPresolveMode (int value) override
void	SetScalingMode (int value) override
	Sets the scaling mode.
void	SetLpAlgorithm (int value) override
Public Member Functions inherited from operations_research::MPSolverInterface
	MPSolverInterface (MPSolver *solver)
virtual	~MPSolverInterface ()
virtual bool	SupportsDirectlySolveProto (std::atomic< bool > *) const
virtual MPSolutionResponse	DirectlySolveProto (LazyMutableCopy< MPModelRequest >, std::atomic< bool > *)
virtual void	Write (const std::string &filename)
virtual bool	AddIndicatorConstraint (MPConstraint *const)
virtual void	BranchingPriorityChangedForVariable (int)
double	best_objective_bound () const
double	objective_value () const
	Returns the objective value of the best solution found so far.
bool	CheckSolutionIsSynchronized () const
virtual bool	CheckSolutionExists () const
bool	CheckSolutionIsSynchronizedAndExists () const
	Handy shortcut to do both checks above (it is often used).
int	last_variable_index () const
	Returns the index of the last variable extracted.
bool	variable_is_extracted (int var_index) const
void	set_variable_as_extracted (int var_index, bool extracted)
bool	constraint_is_extracted (int ct_index) const
void	set_constraint_as_extracted (int ct_index, bool extracted)
bool	quiet () const
	Returns the boolean indicating the verbosity of the solver output.
void	set_quiet (bool quiet_value)
	Sets the boolean indicating the verbosity of the solver output.
MPSolver::ResultStatus	result_status () const
	Returns the result status of the last solve.
virtual double	ComputeExactConditionNumber () const
virtual void	SetStartingLpBasis (const std::vector< MPSolver::BasisStatus > &, const std::vector< MPSolver::BasisStatus > &)
	See MPSolver::SetStartingLpBasis().
virtual double	infinity ()
virtual bool	InterruptSolve ()
virtual bool	NextSolution ()
	See MPSolver::NextSolution() for contract.
virtual void	SetCallback (MPCallback *)
	See MPSolver::SetCallback() for details.
virtual bool	SupportsCallbacks () const

Additional Inherited Members
Public Types inherited from operations_research::MPSolverInterface
enum	SynchronizationStatus { MUST_RELOAD , MODEL_SYNCHRONIZED , SOLUTION_SYNCHRONIZED }
Static Public Attributes inherited from operations_research::MPSolverInterface
static constexpr int64_t	kUnknownNumberOfIterations = -1
static constexpr int64_t	kUnknownNumberOfNodes = -1
Protected Member Functions inherited from operations_research::MPSolverInterface
void	ExtractModel ()
	Extracts model stored in MPSolver.
void	ResetExtractionInformation ()
	Resets the extraction information.
void	InvalidateSolutionSynchronization ()
void	SetCommonParameters (const MPSolverParameters &param)
	Sets parameters common to LP and MIP in the underlying solver.
void	SetMIPParameters (const MPSolverParameters &param)
	Sets MIP specific parameters in the underlying solver.
void	SetUnsupportedDoubleParam (MPSolverParameters::DoubleParam param)
	Sets an unsupported double parameter.
virtual void	SetUnsupportedIntegerParam (MPSolverParameters::IntegerParam param)
	Sets an unsupported integer parameter.
void	SetDoubleParamToUnsupportedValue (MPSolverParameters::DoubleParam param, double value)
	Sets a supported double parameter to an unsupported value.
virtual void	SetIntegerParamToUnsupportedValue (MPSolverParameters::IntegerParam param, int value)
	Sets a supported integer parameter to an unsupported value.
virtual absl::Status	SetNumThreads (int num_threads)
	Sets the number of threads to be used by the solver.
virtual bool	SetSolverSpecificParametersAsString (const std::string &parameters)
Protected Attributes inherited from operations_research::MPSolverInterface
MPSolver *const	solver_
SynchronizationStatus	sync_status_
	Indicates whether the model and the solution are synchronized.
MPSolver::ResultStatus	result_status_
bool	maximize_
	Optimization direction.
int	last_constraint_index_
	Index in MPSolver::variables_ of last constraint extracted.
int	last_variable_index_
	Index in MPSolver::constraints_ of last variable extracted.
double	objective_value_
	The value of the objective function.
double	best_objective_bound_
	The value of the best objective bound. Used only for MIP solvers.
bool	quiet_
	Boolean indicator for the verbosity of the solver output.
Static Protected Attributes inherited from operations_research::MPSolverInterface
static const int	kDummyVariableIndex = 0
	-------— MPSolverInterface -------—

Constructor & Destructor Documentation

◆ KnapsackInterface()

operations_research::KnapsackInterface::KnapsackInterface ( MPSolver * solver )

explicit

Definition at line 97 of file knapsack_interface.cc.

◆ ~KnapsackInterface()

operations_research::KnapsackInterface::~KnapsackInterface ( )

override

Definition at line 100 of file knapsack_interface.cc.

Member Function Documentation

◆ AddRowConstraint()

void operations_research::KnapsackInterface::AddRowConstraint ( MPConstraint * ct )

overridevirtual

Adds a linear constraint.

Implements operations_research::MPSolverInterface.

Definition at line 164 of file knapsack_interface.cc.

◆ AddVariable()

void operations_research::KnapsackInterface::AddVariable ( MPVariable * var )

overridevirtual

Add a variable.

Implements operations_research::MPSolverInterface.

Definition at line 168 of file knapsack_interface.cc.

◆ ClearConstraint()

void operations_research::KnapsackInterface::ClearConstraint ( MPConstraint * constraint )

overridevirtual

Clears a constraint from all its terms.

Implements operations_research::MPSolverInterface.

Definition at line 178 of file knapsack_interface.cc.

◆ ClearObjective()

void operations_research::KnapsackInterface::ClearObjective ( )

overridevirtual

Clears the objective from all its terms.

Implements operations_research::MPSolverInterface.

Definition at line 191 of file knapsack_interface.cc.

◆ column_status()

MPSolver::BasisStatus operations_research::KnapsackInterface::column_status ( int variable_index ) const

overridevirtual

Returns the basis status of a constraint.

Todo: (user): set properly.

Implements operations_research::MPSolverInterface.

Definition at line 203 of file knapsack_interface.cc.

◆ ExtractNewConstraints()

void operations_research::KnapsackInterface::ExtractNewConstraints ( )

overridevirtual

Extracts the constraints that have not been extracted yet.

Removing the contribution of variables fixed to 1 from the constraint upper bound. All fixed variables have a zero coefficient.

Adding upper bound to the coefficients to scale.

Implements operations_research::MPSolverInterface.

Definition at line 228 of file knapsack_interface.cc.

◆ ExtractNewVariables()

void operations_research::KnapsackInterface::ExtractNewVariables ( )

overridevirtual

Extracts the variables that have not been extracted yet.

Implements operations_research::MPSolverInterface.

Definition at line 221 of file knapsack_interface.cc.

◆ ExtractObjective()

void operations_research::KnapsackInterface::ExtractObjective ( )

overridevirtual

Extracts the objective.

Whether fixed to 0 or 1, fixed variables are removed from the profit function, which for the current implementation means their coefficient is set to 0.

Implements operations_research::MPSolverInterface.

Definition at line 272 of file knapsack_interface.cc.

◆ IsContinuous()

bool operations_research::KnapsackInterface::IsContinuous ( ) const

overridevirtual

--— Misc --—

Implements operations_research::MPSolverInterface.

Definition at line 209 of file knapsack_interface.cc.

◆ IsLP()

bool operations_research::KnapsackInterface::IsLP ( ) const

overridevirtual

Returns true if the problem is continuous and linear.

Implements operations_research::MPSolverInterface.

Definition at line 211 of file knapsack_interface.cc.

◆ IsMIP()

bool operations_research::KnapsackInterface::IsMIP ( ) const

overridevirtual

Returns true if the problem is discrete and linear.

Implements operations_research::MPSolverInterface.

Definition at line 213 of file knapsack_interface.cc.

◆ iterations()

int64_t operations_research::KnapsackInterface::iterations ( ) const

overridevirtual

---— Query statistics on the solution and the solve ---—

Implements operations_research::MPSolverInterface.

Definition at line 193 of file knapsack_interface.cc.

◆ nodes()

int64_t operations_research::KnapsackInterface::nodes ( ) const

overridevirtual

Returns the number of branch-and-bound nodes. The problem must be discrete, otherwise it crashes, or returns kUnknownNumberOfNodes in NDEBUG mode.

Implements operations_research::MPSolverInterface.

Definition at line 195 of file knapsack_interface.cc.

◆ Reset()

void operations_research::KnapsackInterface::Reset ( )

overridevirtual

--— Model modifications and extraction --—

Implements operations_research::MPSolverInterface.

Definition at line 140 of file knapsack_interface.cc.

◆ row_status()

MPSolver::BasisStatus operations_research::KnapsackInterface::row_status ( int constraint_index ) const

overridevirtual

Returns the basis status of a row.

Todo: (user): set properly.

Implements operations_research::MPSolverInterface.

Definition at line 197 of file knapsack_interface.cc.

◆ SetCoefficient()

void operations_research::KnapsackInterface::SetCoefficient	(	MPConstraint *	constraint,
		const MPVariable *	variable,
		double	new_value,
		double	old_value )

overridevirtual

Changes a coefficient in a constraint.

Implements operations_research::MPSolverInterface.

Definition at line 172 of file knapsack_interface.cc.

◆ SetConstraintBounds()

void operations_research::KnapsackInterface::SetConstraintBounds	(	int	index,
		double	lb,
		double	ub )

overridevirtual

Modify bounds of an extracted variable.

Implements operations_research::MPSolverInterface.

Definition at line 160 of file knapsack_interface.cc.

◆ SetDualTolerance()

void operations_research::KnapsackInterface::SetDualTolerance ( double value )

overridevirtual

Implements operations_research::MPSolverInterface.

Definition at line 304 of file knapsack_interface.cc.

◆ SetLpAlgorithm()

void operations_research::KnapsackInterface::SetLpAlgorithm ( int value )

overridevirtual

Implements operations_research::MPSolverInterface.

Definition at line 310 of file knapsack_interface.cc.

◆ SetObjectiveCoefficient()

void operations_research::KnapsackInterface::SetObjectiveCoefficient	(	const MPVariable *	variable,
		double	coefficient )

overridevirtual

Changes a coefficient in the linear objective.

Implements operations_research::MPSolverInterface.

Definition at line 182 of file knapsack_interface.cc.

◆ SetObjectiveOffset()

void operations_research::KnapsackInterface::SetObjectiveOffset ( double value )

overridevirtual

Changes the constant term in the linear objective.

Implements operations_research::MPSolverInterface.

Definition at line 187 of file knapsack_interface.cc.

◆ SetOptimizationDirection()

void operations_research::KnapsackInterface::SetOptimizationDirection ( bool maximize )

overridevirtual

Sets the optimization direction (min/max).

Implements operations_research::MPSolverInterface.

Definition at line 148 of file knapsack_interface.cc.

◆ SetParameters()

void operations_research::KnapsackInterface::SetParameters ( const MPSolverParameters & param )

overridevirtual

Sets all parameters in the underlying solver.

Implements operations_research::MPSolverInterface.

Definition at line 296 of file knapsack_interface.cc.

◆ SetPresolveMode()

void operations_research::KnapsackInterface::SetPresolveMode ( int value )

overridevirtual

Implements operations_research::MPSolverInterface.

Definition at line 306 of file knapsack_interface.cc.

◆ SetPrimalTolerance()

void operations_research::KnapsackInterface::SetPrimalTolerance ( double value )

overridevirtual

Implements operations_research::MPSolverInterface.

Definition at line 302 of file knapsack_interface.cc.

◆ SetRelativeMipGap()

void operations_research::KnapsackInterface::SetRelativeMipGap ( double value )

overridevirtual

Sets each parameter in the underlying solver.

Implements operations_research::MPSolverInterface.

Definition at line 300 of file knapsack_interface.cc.

◆ SetScalingMode()

void operations_research::KnapsackInterface::SetScalingMode ( int value )

overridevirtual

Sets the scaling mode.

Implements operations_research::MPSolverInterface.

Definition at line 308 of file knapsack_interface.cc.

◆ SetVariableBounds()

void operations_research::KnapsackInterface::SetVariableBounds	(	int	index,
		double	lb,
		double	ub )

overridevirtual

Modifies bounds of an extracted variable.

Implements operations_research::MPSolverInterface.

Definition at line 152 of file knapsack_interface.cc.

◆ SetVariableInteger()

void operations_research::KnapsackInterface::SetVariableInteger	(	int	index,
		bool	integer )

overridevirtual

Modifies integrality of an extracted variable.

Implements operations_research::MPSolverInterface.

Definition at line 156 of file knapsack_interface.cc.

◆ Solve()

MPSolver::ResultStatus operations_research::KnapsackInterface::Solve ( const MPSolverParameters & param )

overridevirtual

--— Solve --—

Todo: (user): Refine Analysis of the model to choose better solvers.

Implements operations_research::MPSolverInterface.

Definition at line 102 of file knapsack_interface.cc.

◆ SolverVersion()

std::string operations_research::KnapsackInterface::SolverVersion ( ) const

overridevirtual

Returns a string describing the underlying solver and its version.

Implements operations_research::MPSolverInterface.

Definition at line 215 of file knapsack_interface.cc.

◆ underlying_solver()

void * operations_research::KnapsackInterface::underlying_solver ( )

overridevirtual

Returns the underlying solver.

Implements operations_research::MPSolverInterface.

Definition at line 219 of file knapsack_interface.cc.

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

ortools/linear_solver/knapsack_interface.cc

Detailed Description

Public Member Functions

Additional Inherited Members

Constructor & Destructor Documentation

◆ KnapsackInterface()

◆ ~KnapsackInterface()

Member Function Documentation

◆ AddRowConstraint()

◆ AddVariable()

◆ ClearConstraint()

◆ ClearObjective()

◆ column_status()

◆ ExtractNewConstraints()

◆ ExtractNewVariables()

◆ ExtractObjective()

◆ IsContinuous()

◆ IsLP()

◆ IsMIP()

◆ iterations()

◆ nodes()

◆ Reset()

◆ row_status()

◆ SetCoefficient()

◆ SetConstraintBounds()

◆ SetDualTolerance()

◆ SetLpAlgorithm()

◆ SetObjectiveCoefficient()

◆ SetObjectiveOffset()

◆ SetOptimizationDirection()

◆ SetParameters()

◆ SetPresolveMode()

◆ SetPrimalTolerance()

◆ SetRelativeMipGap()

◆ SetScalingMode()

◆ SetVariableBounds()

◆ SetVariableInteger()

◆ Solve()

◆ SolverVersion()

◆ underlying_solver()