useless_constraint_action Class Reference

#include <CoinPresolveUseless.hpp>

Inheritance diagram for useless_constraint_action:

Collaboration diagram for useless_constraint_action:

List of all members.

Classes
struct	action
Public Member Functions
const char *	name () const
	A name for debug printing.
void	postsolve (CoinPostsolveMatrix *prob) const
	Apply the postsolve transformation for this particular presolve action.
virtual	~useless_constraint_action ()
Static Public Member Functions
static const CoinPresolveAction *	presolve (CoinPresolveMatrix *prob, const int *useless_rows, int nuseless_rows, const CoinPresolveAction *next)
Related Functions
(Note that these are not member functions.)
const CoinPresolveAction *	testRedundant (CoinPresolveMatrix *prob, const CoinPresolveAction *next)
	Scan constraints looking for useless constraints.

---

Detailed Description

Definition at line 10 of file CoinPresolveUseless.hpp.

---

Constructor & Destructor Documentation

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.

---

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

• src/CoinPresolveUseless.hpp