abacus::SetBranchRule Class Reference

Implements a branching rule for setting a binary variable to its lower or upper bound. More...

#include <ogdf/lib/abacus/setbranchrule.h>

Inheritance diagram for abacus::SetBranchRule:

Public Member Functions
	SetBranchRule (Master *master, int variable, FSVarStat::STATUS status)
	Creates a branching rule for setting binary variable according to status.
virtual	~SetBranchRule ()
virtual bool	branchOnSetVar () override
	Redefined for returning true, as this branching rule is setting a binary variable.
virtual void	extract (LpSub *lp) override
	Overloaded to modify directly the linear programming relaxation.
virtual int	extract (Sub *sub) override
	Modifies a subproblem by setting the branching variable.
bool	setToUpperBound () const
	Returns true if the branching variable is set to the upper bound, false otherwise.
virtual void	unExtract (LpSub *lp) override
	Should undo the modifictions of the linear programming relaxtion |lp|.
int	variable () const
	Returns the number of the branching variable.
Public Member Functions inherited from abacus::BranchRule
	BranchRule (Master *master)
	Initializes a branching rule.
virtual	~BranchRule ()
virtual void	initialize (Sub *sub)
	Called from the constructor of a subproblem.
Public Member Functions inherited from abacus::AbacusRoot
virtual	~AbacusRoot ()
	The destructor.

Private Attributes
double	oldLpBound_
	The bound of the branching variable in the LP before it is temporarily modified for testing the quality of this branching rule.
FSVarStat::STATUS	status_
	The status of the branching variable.
int	variable_
	The branching variable.

Friends
std::ostream &	operator<< (std::ostream &out, const SetBranchRule &rhs)
	Output operator for set branching rules.

Additional Inherited Members
Static Public Member Functions inherited from abacus::AbacusRoot
static bool	ascii2bool (const string &str)
	Converts the string str to a boolean value.
static bool	endsWith (const string &str, const string &end)
	Returns true if str ends with end, false otherwise.
static double	fracPart (double x)
	Returns the absolute value of the fractional part of x.
static const char *	onOff (bool value)
	Converts a boolean variable to the strings "on" and "off".
Protected Attributes inherited from abacus::BranchRule
Master *	master_
	A pointer to the corresponding master of the optimization.

Detailed Description

Implements a branching rule for setting a binary variable to its lower or upper bound.

Definition at line 42 of file setbranchrule.h.

Constructor & Destructor Documentation

SetBranchRule()

abacus::SetBranchRule::SetBranchRule ( Master *  master, int  variable, FSVarStat::STATUS  status  )

inline

Creates a branching rule for setting binary variable according to status.

Parameters

master	A pointer to the corresponding master of the optimization.
variable	The branching variable.
status	The status the variable is set to (SetToLowerBound or SetToUpperBound).

Definition at line 51 of file setbranchrule.h.

~SetBranchRule()

virtual abacus::SetBranchRule::~SetBranchRule ( )

inlinevirtual

Definition at line 55 of file setbranchrule.h.

Member Function Documentation

branchOnSetVar()

virtual bool abacus::SetBranchRule::branchOnSetVar ( )

inlineoverridevirtual

Redefined for returning true, as this branching rule is setting a binary variable.

Returns

Always true.

Reimplemented from abacus::BranchRule.

Definition at line 98 of file setbranchrule.h.

extract() [1/2]

virtual void abacus::SetBranchRule::extract ( LpSub *  lp )

overridevirtual

Overloaded to modify directly the linear programming relaxation.

This required to evaluate the quality of a branching rule with linear programming methods. The changes have to be undone with the function unextract() before the next linear program is solved.

Parameters

lp	A pointer to the linear programming relaxation of a subproblem.

Reimplemented from abacus::BranchRule.

extract() [2/2]

virtual int abacus::SetBranchRule::extract ( Sub *  sub )

overridevirtual

Modifies a subproblem by setting the branching variable.

• Returns

  0 If the subproblem can be modified according to the branching rule.

  1 If a contradiction occurs.

  Parameters

  sub	The subproblem being modified.

Implements abacus::BranchRule.

setToUpperBound()

bool abacus::SetBranchRule::setToUpperBound ( ) const

inline

Returns true if the branching variable is set to the upper bound, false otherwise.

Definition at line 104 of file setbranchrule.h.

unExtract()

virtual void abacus::SetBranchRule::unExtract ( LpSub *  lp )

overridevirtual

Should undo the modifictions of the linear programming relaxtion |lp|.

This function has to be redefined in a derived class if extract(LpSub*) is redefined there.

Parameters

lp	A pointer to a the linear programming relaxtion of a subproblem.

Reimplemented from abacus::BranchRule.

variable()

int abacus::SetBranchRule::variable ( ) const

inline

Returns the number of the branching variable.

Definition at line 110 of file setbranchrule.h.

Friends And Related Symbol Documentation

operator<<

std::ostream & operator<< ( std::ostream &  out, const SetBranchRule &  rhs  )

friend

Output operator for set branching rules.

Writes the number of the branching variable and its status to the output stream out.

Parameters

out	The output stream.
rhs	The branching rule being output.

Returns

A reference to the output stream.

Member Data Documentation

oldLpBound_

double abacus::SetBranchRule::oldLpBound_

private

The bound of the branching variable in the LP before it is temporarily modified for testing the quality of this branching rule.

The previous LP bound.

Definition at line 123 of file setbranchrule.h.

status_

FSVarStat::STATUS abacus::SetBranchRule::status_

private

The status of the branching variable.

Definition at line 117 of file setbranchrule.h.

variable_

int abacus::SetBranchRule::variable_

private

The branching variable.

Definition at line 116 of file setbranchrule.h.

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

• include/ogdf/lib/abacus/setbranchrule.h