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useless_constraint_action Class Reference

#include <CoinPresolveUseless.hpp>

+ Inheritance diagram for useless_constraint_action:
+ Collaboration diagram for useless_constraint_action:


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

Additional Inherited Members

- Public Attributes inherited from CoinPresolveAction
const CoinPresolveActionnext
 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 
virtual useless_constraint_action::~useless_constraint_action ( )

Member Function Documentation

const char* useless_constraint_action::name ( ) const

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 
void useless_constraint_action::postsolve ( CoinPostsolveMatrix prob) const

Apply the postsolve transformation for this particular presolve action.

Implements CoinPresolveAction.

Friends And Related Function Documentation

const CoinPresolveAction * testRedundant ( CoinPresolveMatrix prob,
const CoinPresolveAction next 

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_

Definition at line 20 of file CoinPresolveUseless.hpp.

const action* const useless_constraint_action::actions_

Definition at line 21 of file CoinPresolveUseless.hpp.

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