DualExpr Class Reference

---

Detailed Description

This data structure represents a column of the matrix, thas is it strores a linear expression of the dual variables (Rows).

There are several ways to access and modify the contents of this container.

• Its it fully compatible with std::map<Row,double>, so for expamle if e is an DualExpr and v and w are of type Row, then you can read and modify the coefficients like these.

         e[v]=5;
         e[v]+=12;
         e.erase(v);
  

  or you can also iterate through its elements.

         double s=0;
         for(LpSolverBase::DualExpr::iterator i=e.begin();i!=e.end();++i)
           s+=i->second;
  

  (This code computes the sum of all coefficients).
• Numbers (double's) and variables (Rows) directly convert to an DualExpr and the usual linear operations are defined, so

         v+w
         2*v-3.12*(v-w/2)
         v*2.1+(3*v+(v*12+w)*3)/2
  

  are valid DualExpressions. The usual assignment operations are also defined.

         e=v+w;
         e+=2*v-3.12*(v-w/2);
         e*=3.4;
         e/=5;
  

See also:

Expr

#include <lemon/lp_base.h>

Inherits std::map<Row,Value>.

List of all members.

Public Member Functions
	DualExpr ()
	DualExpr (const Key &v)
void	set (const Key &v, const Value &c)
void	simplify ()
	Removes the components with zero coefficient.
void	simplify (double &tolerance)
	Removes the coefficients closer to zero than tolerance.
void	clear ()
	Sets all coefficients to 0.
DualExpr &	operator+= (const DualExpr &e)
DualExpr &	operator-= (const DualExpr &e)
DualExpr &	operator*= (const Value &c)
DualExpr &	operator/= (const Value &c)
Related Functions
(Note that these are not member functions.)
LpSolverBase::DualExpr	operator+ (const LpSolverBase::DualExpr &a, const LpSolverBase::DualExpr &b)
LpSolverBase::DualExpr	operator- (const LpSolverBase::DualExpr &a, const LpSolverBase::DualExpr &b)
LpSolverBase::DualExpr	operator* (const LpSolverBase::DualExpr &a, const LpSolverBase::Value &b)
LpSolverBase::DualExpr	operator* (const LpSolverBase::Value &a, const LpSolverBase::DualExpr &b)
LpSolverBase::DualExpr	operator/ (const LpSolverBase::DualExpr &a, const LpSolverBase::Value &b)