LpBase::Constr Class Reference

Detailed Description

This data stucture represents a linear constraint in the LP. Basically it is a linear expression with a lower or an upper bound (or both). These parts of the constraint can be obtained by the member functions expr(), lowerBound() and upperBound(), respectively. There are two ways to construct a constraint.

• You can set the linear expression and the bounds directly by the functions above.
• The operators <=, == and >= are defined between expressions, or even between constraints whenever it makes sense. Therefore if e and f are linear expressions and s and t are numbers, then the followings are valid expressions and thus they can be used directly e.g. in addRow() whenever it makes sense.

  e<=s
  e<=f
  e==f
  s<=e<=t
  e>=t

  Warning

  The validity of a constraint is checked only at run time, so e.g. addRow(x[1]<=x[2]<=5) will compile, but will fail an assertion.

#include <lemon/lp_base.h>

Public Member Functions
	Constr ()
	Constr (Value lb, const Expr &e, Value ub)
void	clear ()
Expr &	expr ()
	Reference to the linear expression.
const Expr &	expr () const
	Cont reference to the linear expression.
Value &	lowerBound ()
	Reference to the lower bound.
const Value &	lowerBound () const
	The const version of lowerBound()
Value &	upperBound ()
	Reference to the upper bound.
const Value &	upperBound () const
	The const version of upperBound()
bool	lowerBounded () const
	Is the constraint lower bounded?
bool	upperBounded () const
	Is the constraint upper bounded?

Related Functions
(Note that these are not member functions.)
LpBase::Constr	operator<= (const LpBase::Expr &e, const LpBase::Expr &f)
	Create constraint.
LpBase::Constr	operator<= (const LpBase::Value &e, const LpBase::Expr &f)
	Create constraint.
LpBase::Constr	operator<= (const LpBase::Expr &e, const LpBase::Value &f)
	Create constraint.
LpBase::Constr	operator>= (const LpBase::Expr &e, const LpBase::Expr &f)
	Create constraint.
LpBase::Constr	operator>= (const LpBase::Value &e, const LpBase::Expr &f)
	Create constraint.
LpBase::Constr	operator>= (const LpBase::Expr &e, const LpBase::Value &f)
	Create constraint.
LpBase::Constr	operator== (const LpBase::Expr &e, const LpBase::Value &f)
	Create constraint.
LpBase::Constr	operator== (const LpBase::Expr &e, const LpBase::Expr &f)
	Create constraint.
LpBase::Constr	operator<= (const LpBase::Value &n, const LpBase::Constr &c)
	Create constraint.
LpBase::Constr	operator<= (const LpBase::Constr &c, const LpBase::Value &n)
	Create constraint.
LpBase::Constr	operator>= (const LpBase::Value &n, const LpBase::Constr &c)
	Create constraint.
LpBase::Constr	operator>= (const LpBase::Constr &c, const LpBase::Value &n)
	Create constraint.

Member Function Documentation

Value& lowerBound ( )

inline

Returns

• INF: the constraint is lower unbounded.
• NaN: lower bound has not been set.
• finite number: the lower bound

Value& upperBound ( )

inline

Returns

• INF: the constraint is upper unbounded.
• NaN: upper bound has not been set.
• finite number: the upper bound