useless_constraint_action Class Reference

#include <CoinPresolveUseless.hpp>

Inheritance diagram for useless_constraint_action:

Collaboration diagram for useless_constraint_action:

Classes
struct	action

Public Member Functions
const char *	name () const
	A name for debug printing. More...
void	postsolve (CoinPostsolveMatrix *prob) const
	Apply the postsolve transformation for this particular presolve action. More...
virtual	~useless_constraint_action ()
Public Member Functions inherited from CoinPresolveAction
	CoinPresolveAction (const CoinPresolveAction *next)
	Construct a postsolve object and add it to the transformation list. More...
void	setNext (const CoinPresolveAction *nextAction)
	modify next (when building rather than passing) More...
virtual	~CoinPresolveAction ()
	Virtual destructor. More...

Static Public Member Functions
static const CoinPresolveAction *	presolve (CoinPresolveMatrix *prob, const int *useless_rows, int nuseless_rows, const CoinPresolveAction *next)
Static Public Member Functions inherited from CoinPresolveAction
static void	throwCoinError (const char *error, const char *ps_routine)
	Stub routine to throw exceptions. More...

Private Member Functions
	useless_constraint_action (int nactions, const action *actions, const CoinPresolveAction *next)

Private Attributes
const int	nactions_
const action *const	actions_

Related Functions
(Note that these are not member functions.)
const CoinPresolveAction *	testRedundant (CoinPresolveMatrix *prob, const CoinPresolveAction *next)
	Scan constraints looking for useless constraints. More...

Additional Inherited Members
Public Attributes inherited from CoinPresolveAction
const CoinPresolveAction *	next
	The next presolve transformation. More...

Detailed Description

Definition at line 10 of file CoinPresolveUseless.hpp.

Constructor & Destructor Documentation

useless_constraint_action::useless_constraint_action ( int  nactions, const action *  actions, const CoinPresolveAction *  next  )

private

virtual useless_constraint_action::~useless_constraint_action ( )

virtual

Member Function Documentation

const char* useless_constraint_action::name ( ) const

virtual

A name for debug printing.

It is expected that the name is not stored in the transform itself.

Implements CoinPresolveAction.

static const CoinPresolveAction* useless_constraint_action::presolve ( CoinPresolveMatrix *  prob, const int *  useless_rows, int  nuseless_rows, const CoinPresolveAction *  next  )

static

void useless_constraint_action::postsolve ( CoinPostsolveMatrix *  prob ) const

virtual

Apply the postsolve transformation for this particular presolve action.

Implements CoinPresolveAction.

Friends And Related Function Documentation

const CoinPresolveAction * testRedundant ( CoinPresolveMatrix *  prob, const CoinPresolveAction *  next  )

related

Scan constraints looking for useless constraints.

A front end to identify useless constraints and hand them to useless_constraint_action::presolve() for processing.

In a bit more detail, the routine implements a greedy algorithm that identifies a set of necessary constraints. A constraint is necessary if it implies a tighter bound on a variable than the original column bound. These tighter column bounds are then used to calculate row activity and identify constraints that are useless given the presence of the necessary constraints.

Member Data Documentation

const int useless_constraint_action::nactions_

private

Definition at line 20 of file CoinPresolveUseless.hpp.

const action* const useless_constraint_action::actions_

private

Definition at line 21 of file CoinPresolveUseless.hpp.

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

• /tmp/Cgl-0.60.3/CoinUtils/src/CoinPresolveUseless.hpp