This class chooses a variable to branch on. More...

#include <BonChooseVariable.hpp>

Classes
class	Messages
Public Types
enum	DoStrongReturnStatuses { provenInfeasible = -1, doneNoFixing, doneCanFix, interuptedCanFix, maxTime }
enum	chooseVariableReturnStatuses { infeasibleNode = -1, hasCandidate, feasibleNode, canFixAndStrongBranch, canFixAndBranch, canFixNoCandidate }
	Return statuses for chooseVariable. More...
Public Member Functions
	BonChooseVariable (BabSetupBase &b, const OsiSolverInterface *solver)
	Constructor from solver (so we can set up arrays etc)
	BonChooseVariable (const BonChooseVariable &)
	Copy constructor.
BonChooseVariable &	operator= (const BonChooseVariable &rhs)
	Assignment operator.
virtual OsiChooseVariable *	clone () const
	Clone.
virtual	~BonChooseVariable ()
	Destructor.
double	maxminCrit (const OsiBranchingInformation *info) const
	Helper functions for setupList and chooseVariable.
void	computeMultipliers (double &upMult, double &downMult) const
double	computeUsefulness (const double MAXMIN_CRITERION, const double upMult, const double dowMult, const double value, const OsiObject *object, int i, double &value2) const
virtual int	setupList (OsiBranchingInformation *info, bool initialize)
	Sets up strong list and clears all if initialize is true.
virtual int	chooseVariable (OsiSolverInterface solver, OsiBranchingInformation info, bool fixVariables)
	Choose a variable Returns -.
virtual void	updateInformation (const OsiBranchingInformation info, int branch, OsiHotInfo hotInfo)
	This is a utility function which does strong branching on a list of objects and stores the results in OsiHotInfo.objects.
virtual void	updateInformation (int whichObject, int branch, double changeInObjective, double changeInValue, int status)
	Given a branch fill in useful information e.g. estimates.
void	setCbcModel (CbcModel *cbc_model)
	Method for setting CbcModel, which is used to get statusOfSearch.
void	setOnlyPseudoWhenTrusted (bool only_pseudo_when_trusted)
const OsiPseudoCosts &	pseudoCosts () const
	Access to pseudo costs storage.
OsiPseudoCosts &	pseudoCosts ()
	Access to pseudo costs storage.
Static Public Member Functions
static void	registerOptions (Ipopt::SmartPtr< Bonmin::RegisteredOptions > roptions)
Protected Types
enum	StrongStatus { NotDone = -1, Feasible, Infeasible, NotFinished }
	Statuses for strong branching candidates. More...
Protected Member Functions
virtual int	doStrongBranching (OsiSolverInterface solver, OsiBranchingInformation info, int numberToDo, int returnCriterion)
	This is a utility function which does strong branching on a list of objects and stores the results in OsiHotInfo.objects.
int	determineStatus (OsiSolverInterface *solver) const
	Determine status of strong branching solution.
bool	isRootNode (const OsiBranchingInformation *info) const
	detecting if this is root node
Protected Attributes
Ipopt::SmartPtr < Ipopt::Journalist >	jnlst_
	Holding on the a pointer to the journalist.
int	bb_log_level_
	verbosity level
vector< HotInfo >	results_
	Stores strong branching results.
CbcModel *	cbc_model_
	CbcModel, used to get status of search.
bool	only_pseudo_when_trusted_
	Flag indicating whether we don't want to mix strong branching and pseudo costs during the decision which variable to branch on.
int	number_not_trusted_
	Number of variables put into the list because there were not trusted.
CoinMessageHandler *	handler_
	Message handler.
Messages	messages_
	Messages.
Algoirithmic options
double	maxmin_crit_no_sol_
	maxmin weight in branching decision when no solution has been found yet
double	maxmin_crit_have_sol_
	maxmin weight in branching decision when no solution has been found yet
double	setup_pseudo_frac_
	fraction of branching candidates that are not trusted yet
int	numberBeforeTrustedList_
	number of times a branch has to happen so that it is trusted in setupList
int	numberStrongRoot_
	number of strong branching points at root node
int	numberStrongBackup_
	backup of numberStrong_ before Root node solve
int	numberLookAhead_
	number of look-ahead strong-branching steps
int	minNumberStrongBranch_
	Always strong branch that many first candidate in the list regardless of numberTrusted.
OsiPseudoCosts	pseudoCosts_
	Stores the pseudo costs.
int	trustStrongForPseudoCosts_
	Wether or not to trust strong branching results for updating pseudo costs.
Static Protected Attributes
static const std::string	CNAME
	Stores the class name for throwing errors.
Private Member Functions
	BonChooseVariable ()
	Default Constructor, forbiden for some reason.
Private Attributes
double	time_limit_
	Global time limit for algorithm.
double	start_time_
	Starting time of algorithm.
Message handling.
enum	Messages_Types { PS_COST_HISTORY = 0, PS_COST_MULT, PS_COST_ESTIMATES, CANDIDATE_LIST, CANDIDATE_LIST2, CANDIDATE_LIST3, SB_START, SB_HEADER, SB_RES, BRANCH_VAR, CHOSEN_VAR, UPDATE_PS_COST, BON_CHOOSE_MESSAGES_DUMMY_END }
void	passInMessageHandler (CoinMessageHandler *handler)
CoinMessageHandler &	message (Messages_Types type) const

Detailed Description

This class chooses a variable to branch on.

This is the base class for the branching rules in Bonmin (inherits from OsiChooseVariable). This class implements a simple strong branching algorithm where the changes in the objective value induced by branching on a specific object are estimated with the pure virtual function fill_changes.

Definition at line 81 of file BonChooseVariable.hpp.

Member Enumeration Documentation

enum Bonmin::BonChooseVariable::StrongStatus [protected]

Statuses for strong branching candidates.

Enumerator:

NotDone
Feasible	Child is proven feasible.
Infeasible	Child is proven infeasible.
NotFinished	Child is not finished.

Definition at line 109 of file BonChooseVariable.hpp.

enum Bonmin::BonChooseVariable::Messages_Types

Enumerator:

PS_COST_HISTORY
PS_COST_MULT
PS_COST_ESTIMATES
CANDIDATE_LIST
CANDIDATE_LIST2
CANDIDATE_LIST3
SB_START
SB_HEADER
SB_RES
BRANCH_VAR
CHOSEN_VAR
UPDATE_PS_COST
BON_CHOOSE_MESSAGES_DUMMY_END

Definition at line 117 of file BonChooseVariable.hpp.

enum Bonmin::BonChooseVariable::DoStrongReturnStatuses

Enumerator:

provenInfeasible
doneNoFixing	All done no variable can be fixed.
doneCanFix	Several variable can be fixed.
interuptedCanFix	Interupted and found a variable to fix.
maxTime	Interupted because of time limit.

Definition at line 153 of file BonChooseVariable.hpp.

enum Bonmin::BonChooseVariable::chooseVariableReturnStatuses

Return statuses for chooseVariable.

Enumerator:

infeasibleNode
hasCandidate	Normal termination, found a variable to branch on.
feasibleNode	All variable are feasible, the node is feasible.
canFixAndStrongBranch	Found variable to fix and also has remaining candidate for strong branching.
canFixAndBranch	Found variable to fix and also has a (non-strong) branching candidate.
canFixNoCandidate	Can fix variables but does not have strong branching candidates.

Definition at line 161 of file BonChooseVariable.hpp.

Constructor & Destructor Documentation

Bonmin::BonChooseVariable::BonChooseVariable	(	BabSetupBase &	b,
		const OsiSolverInterface *	solver
	)

Constructor from solver (so we can set up arrays etc)

Bonmin::BonChooseVariable::BonChooseVariable ( const BonChooseVariable & )

Copy constructor.

virtual Bonmin::BonChooseVariable::~BonChooseVariable ( ) [virtual]

Destructor.

Bonmin::BonChooseVariable::BonChooseVariable ( ) [private]

Default Constructor, forbiden for some reason.

Member Function Documentation

virtual int Bonmin::BonChooseVariable::doStrongBranching	(	OsiSolverInterface *	solver,
		OsiBranchingInformation *	info,
		int	numberToDo,
		int	returnCriterion
	)		`[protected, virtual]`

This is a utility function which does strong branching on a list of objects and stores the results in OsiHotInfo.objects.

On entry the object sequence is stored in the OsiHotInfo object and maybe more. It returns - -1 - one branch was infeasible both ways 0 - all inspected - nothing can be fixed 1 - all inspected - some can be fixed (returnCriterion==0) 2 - may be returning early - one can be fixed (last one done) (returnCriterion==1) 3 - returning because max time

void Bonmin::BonChooseVariable::passInMessageHandler ( CoinMessageHandler * handler ) [inline]

Definition at line 139 of file BonChooseVariable.hpp.

References handler_.

CoinMessageHandler& Bonmin::BonChooseVariable::message ( Messages_Types type ) const [inline]

Definition at line 146 of file BonChooseVariable.hpp.

References handler_, and messages_.

BonChooseVariable& Bonmin::BonChooseVariable::operator= ( const BonChooseVariable & rhs )

Assignment operator.

virtual OsiChooseVariable* Bonmin::BonChooseVariable::clone ( ) const [virtual]

Clone.

static void Bonmin::BonChooseVariable::registerOptions ( Ipopt::SmartPtr< Bonmin::RegisteredOptions > roptions ) [static]

double Bonmin::BonChooseVariable::maxminCrit ( const OsiBranchingInformation * info ) const

Helper functions for setupList and chooseVariable.

void Bonmin::BonChooseVariable::computeMultipliers	(	double &	upMult,
		double &	downMult
	)		const

double Bonmin::BonChooseVariable::computeUsefulness	(	const double	MAXMIN_CRITERION,
		const double	upMult,
		const double	dowMult,
		const double	value,
		const OsiObject *	object,
		int	i,
		double &	value2
	)		const

virtual int Bonmin::BonChooseVariable::setupList	(	OsiBranchingInformation *	info,
		bool	initialize
	)		`[virtual]`

Sets up strong list and clears all if initialize is true.

Returns number of infeasibilities.

virtual int Bonmin::BonChooseVariable::chooseVariable	(	OsiSolverInterface *	solver,
		OsiBranchingInformation *	info,
		bool	fixVariables
	)		`[virtual]`

Choose a variable Returns -.

-1 Node is infeasible 0 Normal termination - we have a candidate 1 All looks satisfied - no candidate 2 We can change the bound on a variable - but we also have a strong branching candidate 3 We can change the bound on a variable - but we have a non-strong branching candidate 4 We can change the bound on a variable - no other candidates We can pick up branch from bestObjectIndex() and bestWhichWay() We can pick up a forced branch (can change bound) from firstForcedObjectIndex() and firstForcedWhichWay() If we have a solution then we can pick up from goodObjectiveValue() and goodSolution() If fixVariables is true then 2,3,4 are all really same as problem changed

virtual void Bonmin::BonChooseVariable::updateInformation	(	const OsiBranchingInformation *	info,
		int	branch,
		OsiHotInfo *	hotInfo
	)		`[virtual]`

This is a utility function which does strong branching on a list of objects and stores the results in OsiHotInfo.objects.

On entry the object sequence is stored in the OsiHotInfo object and maybe more. It returns - -1 - one branch was infeasible both ways 0 - all inspected - nothing can be fixed 1 - all inspected - some can be fixed (returnCriterion==0) 2 - may be returning early - one can be fixed (last one done) (returnCriterion==1) 3 - returning because max time Given a candidate fill in useful information e.g. estimates

virtual void Bonmin::BonChooseVariable::updateInformation	(	int	whichObject,
		int	branch,
		double	changeInObjective,
		double	changeInValue,
		int	status
	)		`[virtual]`