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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 CoinPresolveActionpresolve (CoinPresolveMatrix *prob, const int *useless_rows, int nuseless_rows, const CoinPresolveAction *next)

Related Functions

(Note that these are not member functions.)

const CoinPresolveActiontestRedundant (CoinPresolveMatrix *prob, const CoinPresolveAction *next)
 Scan constraints looking for useless constraints.

Detailed Description

Definition at line 10 of file CoinPresolveUseless.hpp.


Constructor & Destructor Documentation


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]

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:
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