Detailed Description

The class for constraints of a Mathematical Programming (MP) model.

A constraint is represented as a linear equation or inequality.

Definition at line 1285 of file linear_solver.h.

#include <linear_solver.h>

Public Member Functions
	MPConstraint (const MPConstraint &)=delete
	This type is neither copyable nor movable.
MPConstraint &	operator= (const MPConstraint &)=delete
const std::string &	name () const
	Returns the name of the constraint.
void	Clear ()
	Clears all variables and coefficients. Does not clear the bounds.
void	SetCoefficient (const MPVariable *var, double coeff)
double	GetCoefficient (const MPVariable *var) const
const absl::flat_hash_map< const MPVariable *, double > &	terms () const
double	lb () const
	Returns the lower bound.
double	ub () const
	Returns the upper bound.
void	SetLB (double lb)
	Sets the lower bound.
void	SetUB (double ub)
	Sets the upper bound.
void	SetBounds (double lb, double ub)
	Sets both the lower and upper bounds.
bool	is_lazy () const
	Advanced usage: returns true if the constraint is "lazy" (see below).
void	set_is_lazy (bool laziness)
const MPVariable *	indicator_variable () const
bool	indicator_value () const
int	index () const
	Returns the index of the constraint in the MPSolver::constraints_.
double	dual_value () const
MPSolver::BasisStatus	basis_status () const

Protected Member Functions
	MPConstraint (int index, double lb, double ub, const std::string &name, MPSolverInterface *const interface_in)
void	set_dual_value (double dual_value)

Friends
class	MPSolver
class	MPSolverInterface
class	CBCInterface
class	CLPInterface
class	GLPKInterface
class	SCIPInterface
class	SLMInterface
class	GurobiInterface
class	CplexInterface
class	XpressInterface
class	GLOPInterface
class	BopInterface
class	SatInterface
class	PdlpInterface
class	HighsInterface
class	KnapsackInterface

Constructor & Destructor Documentation

◆ MPConstraint() [1/2]

operations_research::MPConstraint::MPConstraint ( const MPConstraint & )

delete

This type is neither copyable nor movable.

◆ MPConstraint() [2/2]

operations_research::MPConstraint::MPConstraint	(	int	index,
		double	lb,
		double	ub,
		const std::string &	name,
		MPSolverInterface *const	interface_in )

inlineprotected

Constructor. A constraint points to a single MPSolverInterface that is specified in the constructor. A constraint cannot belong to several models.

Definition at line 1402 of file linear_solver.h.

Member Function Documentation

◆ basis_status()

MPSolver::BasisStatus operations_research::MPConstraint::basis_status ( ) const

Advanced usage: returns the basis status of the constraint.

It is only available for continuous problems).

Note that if a constraint "linear_expression in [lb, ub]" is transformed into "linear_expression + slack = 0" with slack in [-ub, -lb], then this status is the same as the status of the slack variable with AT_UPPER_BOUND and AT_LOWER_BOUND swapped.

See also: MPSolver::BasisStatus.

This is done lazily as this method is expected to be rarely used.

Definition at line 168 of file linear_solver.cc.

◆ Clear()

void operations_research::MPConstraint::Clear ( )

Clears all variables and coefficients. Does not clear the bounds.

Definition at line 145 of file linear_solver.cc.

◆ dual_value()

double operations_research::MPConstraint::dual_value ( ) const

Advanced usage: returns the dual value of the constraint in the current solution (only available for continuous problems).

Definition at line 159 of file linear_solver.cc.

◆ GetCoefficient()

double operations_research::MPConstraint::GetCoefficient ( const MPVariable * var ) const

Gets the coefficient of a given variable on the constraint (which is 0 if the variable does not appear in the constraint).

Definition at line 113 of file linear_solver.cc.

◆ index()

int operations_research::MPConstraint::index ( ) const

inline

Returns the index of the constraint in the MPSolver::constraints_.

Definition at line 1359 of file linear_solver.h.

◆ indicator_value()

bool operations_research::MPConstraint::indicator_value ( ) const

inline

Definition at line 1356 of file linear_solver.h.

◆ indicator_variable()

const MPVariable * operations_research::MPConstraint::indicator_variable ( ) const

inline

Definition at line 1355 of file linear_solver.h.

◆ is_lazy()

bool operations_research::MPConstraint::is_lazy ( ) const

inline

Advanced usage: returns true if the constraint is "lazy" (see below).

Definition at line 1338 of file linear_solver.h.

◆ lb()

double operations_research::MPConstraint::lb ( ) const

inline

Returns the lower bound.

Definition at line 1323 of file linear_solver.h.

◆ name()

const std::string & operations_research::MPConstraint::name ( ) const

inline

Returns the name of the constraint.

Definition at line 1294 of file linear_solver.h.

◆ operator=()

MPConstraint & operations_research::MPConstraint::operator= ( const MPConstraint & )

delete

◆ set_dual_value()

void operations_research::MPConstraint::set_dual_value ( double dual_value )

inlineprotected

Definition at line 1414 of file linear_solver.h.

◆ set_is_lazy()

void operations_research::MPConstraint::set_is_lazy ( bool laziness )

inline

Advanced usage: sets the constraint "laziness".

This is only supported for SCIP and has no effect on other solvers.

When laziness is true, the constraint is only considered by the Linear Programming solver if its current solution violates the constraint. In this case, the constraint is definitively added to the problem. This may be useful in some MIP problems, and may have a dramatic impact on performance.

For more info see: http://tinyurl.com/lazy-constraints.

Definition at line 1353 of file linear_solver.h.

◆ SetBounds()

void operations_research::MPConstraint::SetBounds	(	double	lb,
		double	ub )

Sets both the lower and upper bounds.

Definition at line 150 of file linear_solver.cc.

◆ SetCoefficient()

void operations_research::MPConstraint::SetCoefficient	(	const MPVariable *	var,
		double	coeff )

Sets the coefficient of the variable on the constraint.

If the variable does not belong to the solver, the function just returns, or crashes in non-opt mode.

If setting a coefficient to 0 when this coefficient did not exist or was already 0, do nothing: skip interface_->SetCoefficient() and do not store a coefficient in the map. Note that if the coefficient being set to 0 did exist and was not 0, we do have to keep a 0 in the coefficients_ map, because the extraction of the constraint might rely on it, depending on the underlying solver.

Definition at line 119 of file linear_solver.cc.

◆ SetLB()

void operations_research::MPConstraint::SetLB ( double lb )

inline

Sets the lower bound.

Definition at line 1329 of file linear_solver.h.

◆ SetUB()

void operations_research::MPConstraint::SetUB ( double ub )

inline

Sets the upper bound.

Definition at line 1332 of file linear_solver.h.

◆ terms()

const absl::flat_hash_map< const MPVariable *, double > & operations_research::MPConstraint::terms ( ) const

inline

Returns a map from variables to their coefficients in the constraint.

If a variable is not present in the map, then its coefficient is zero.

Definition at line 1318 of file linear_solver.h.

◆ ub()

double operations_research::MPConstraint::ub ( ) const

inline

Returns the upper bound.

Definition at line 1326 of file linear_solver.h.

◆ BopInterface

friend class BopInterface

friend

Definition at line 1393 of file linear_solver.h.

◆ CBCInterface

friend class CBCInterface

friend

Definition at line 1384 of file linear_solver.h.

◆ CLPInterface

friend class CLPInterface

friend

Definition at line 1385 of file linear_solver.h.

◆ CplexInterface

friend class CplexInterface

friend

Definition at line 1390 of file linear_solver.h.

◆ GLOPInterface

friend class GLOPInterface

friend

Definition at line 1392 of file linear_solver.h.

◆ GLPKInterface

friend class GLPKInterface

friend

Definition at line 1386 of file linear_solver.h.

◆ GurobiInterface

friend class GurobiInterface

friend

Definition at line 1389 of file linear_solver.h.

◆ HighsInterface

friend class HighsInterface

friend

Definition at line 1396 of file linear_solver.h.

◆ KnapsackInterface

friend class KnapsackInterface

friend

Definition at line 1397 of file linear_solver.h.

◆ MPSolver

friend class MPSolver

friend

Definition at line 1382 of file linear_solver.h.

◆ MPSolverInterface

friend class MPSolverInterface

friend

Definition at line 1383 of file linear_solver.h.

◆ PdlpInterface

friend class PdlpInterface

friend

Definition at line 1395 of file linear_solver.h.

◆ SatInterface

friend class SatInterface

friend

Definition at line 1394 of file linear_solver.h.

◆ SCIPInterface

friend class SCIPInterface

friend

Definition at line 1387 of file linear_solver.h.

◆ SLMInterface

friend class SLMInterface

friend

Definition at line 1388 of file linear_solver.h.

◆ XpressInterface

friend class XpressInterface

friend

Definition at line 1391 of file linear_solver.h.

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

ortools/linear_solver/linear_solver.h
ortools/linear_solver/linear_solver.cc

Detailed Description

Public Member Functions

Protected Member Functions

Friends

Constructor & Destructor Documentation

◆ MPConstraint() [1/2]

◆ MPConstraint() [2/2]

Member Function Documentation

◆ basis_status()

◆ Clear()

◆ dual_value()

◆ GetCoefficient()

◆ index()

◆ indicator_value()

◆ indicator_variable()

◆ is_lazy()

◆ lb()

◆ name()

◆ operator=()

◆ set_dual_value()

◆ set_is_lazy()

◆ SetBounds()

◆ SetCoefficient()

◆ SetLB()

◆ SetUB()

◆ terms()

◆ ub()

Friends And Related Symbol Documentation

◆ BopInterface

◆ CBCInterface

◆ CLPInterface

◆ CplexInterface

◆ GLOPInterface

◆ GLPKInterface

◆ GurobiInterface

◆ HighsInterface

◆ KnapsackInterface

◆ MPSolver

◆ MPSolverInterface

◆ PdlpInterface

◆ SatInterface

◆ SCIPInterface

◆ SLMInterface

◆ XpressInterface