MPConstraint

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 1231 of file linear_solver.h.

Public Member Functions
const std::string &	name () const
	Returns the name of the constraint. More...
void	Clear ()
	Clears all variables and coefficients. Does not clear the bounds. More...
void	SetCoefficient (const MPVariable *const var, double coeff)
	Sets the coefficient of the variable on the constraint. More...
double	GetCoefficient (const MPVariable *const var) const
	Gets the coefficient of a given variable on the constraint (which is 0 if the variable does not appear in the constraint). More...
const absl::flat_hash_map< const MPVariable *, double > &	terms () const
	Returns a map from variables to their coefficients in the constraint. More...
double	lb () const
	Returns the lower bound. More...
double	ub () const
	Returns the upper bound. More...
void	SetLB (double lb)
	Sets the lower bound. More...
void	SetUB (double ub)
	Sets the upper bound. More...
void	SetBounds (double lb, double ub)
	Sets both the lower and upper bounds. More...
bool	is_lazy () const
	Advanced usage: returns true if the constraint is "lazy" (see below). More...
void	set_is_lazy (bool laziness)
	Advanced usage: sets the constraint "laziness". More...
const MPVariable *	indicator_variable () const
bool	indicator_value () const
int	index () const
	Returns the index of the constraint in the MPSolver::constraints_. More...
double	dual_value () const
	Advanced usage: returns the dual value of the constraint in the current solution (only available for continuous problems). More...
MPSolver::BasisStatus	basis_status () const
	Advanced usage: returns the basis status of the constraint. More...

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)

Constructor & Destructor Documentation

MPConstraint()

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

inlineprotected

Definition at line 1342 of file linear_solver.h.

Member Function Documentation

basis_status()

MPSolver::BasisStatus 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.

Definition at line 158 of file linear_solver.cc.

Clear()

void Clear

(

)

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

Definition at line 135 of file linear_solver.cc.

dual_value()

double dual_value

(

)

const

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

Definition at line 149 of file linear_solver.cc.

GetCoefficient()

double GetCoefficient

(

const MPVariable *const

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 103 of file linear_solver.cc.

index()

int index ( ) const

inline

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

Definition at line 1299 of file linear_solver.h.

indicator_value()

bool indicator_value ( ) const

inline

Definition at line 1296 of file linear_solver.h.

indicator_variable()

const MPVariable* indicator_variable ( ) const

inline

Definition at line 1295 of file linear_solver.h.

is_lazy()

bool is_lazy ( ) const

inline

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

Definition at line 1278 of file linear_solver.h.

lb()

double lb ( ) const

inline

Returns the lower bound.

Definition at line 1263 of file linear_solver.h.

name()

const std::string& name ( ) const

inline

Returns the name of the constraint.

Definition at line 1234 of file linear_solver.h.

set_dual_value()

void set_dual_value ( double  dual_value )

inlineprotected

Definition at line 1354 of file linear_solver.h.

set_is_lazy()

void 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 1293 of file linear_solver.h.

SetBounds()

void SetBounds	(	double	lb,
		double	ub
	)

Sets both the lower and upper bounds.

Definition at line 140 of file linear_solver.cc.

SetCoefficient()

void SetCoefficient	(	const MPVariable *const	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.

Definition at line 109 of file linear_solver.cc.

SetLB()

void SetLB ( double  lb )

inline

Sets the lower bound.

Definition at line 1269 of file linear_solver.h.

SetUB()

void SetUB ( double  ub )

inline

Sets the upper bound.

Definition at line 1272 of file linear_solver.h.

terms()

const absl::flat_hash_map<const MPVariable*, double>& 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 1258 of file linear_solver.h.

ub()

double ub ( ) const

inline

Returns the upper bound.

Definition at line 1266 of file linear_solver.h.

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

• linear_solver.h
• linear_solver.cc