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drop_empty_cols_action Class Reference

Physically removes empty columns in presolve, and reinserts empty columns in postsolve. More...

#include <CoinPresolveEmpty.hpp>

+ Inheritance diagram for drop_empty_cols_action:
+ Collaboration diagram for drop_empty_cols_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 ~drop_empty_cols_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 *, const int *ecols, int necols, const CoinPresolveAction *)
 
static const CoinPresolveActionpresolve (CoinPresolveMatrix *prob, 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

 drop_empty_cols_action (int nactions, const action *const actions, const CoinPresolveAction *next)
 

Private Attributes

const int nactions_
 
const action *const actions_
 

Additional Inherited Members

- Public Attributes inherited from CoinPresolveAction
const CoinPresolveActionnext
 The next presolve transformation. More...
 

Detailed Description

Physically removes empty columns in presolve, and reinserts empty columns in postsolve.

Physical removal of rows and columns should be the last activities performed during presolve. Do them exactly once. The row-major matrix is not maintained by this transform.

To physically drop the columns, CoinPrePostsolveMatrix::mcstrt_ and CoinPrePostsolveMatrix::hincol_ are compressed, along with column bounds, objective, and (if present) the column portions of the solution. This renumbers the columns. drop_empty_cols_action::presolve will reconstruct CoinPresolveMatrix::clink_.

Todo:
Confirm correct behaviour with solution in presolve.

Definition at line 34 of file CoinPresolveEmpty.hpp.

Constructor & Destructor Documentation

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

Definition at line 47 of file CoinPresolveEmpty.hpp.

virtual drop_empty_cols_action::~drop_empty_cols_action ( )
inlinevirtual

Definition at line 68 of file CoinPresolveEmpty.hpp.

Member Function Documentation

const char* drop_empty_cols_action::name ( ) const
inlinevirtual

A name for debug printing.

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

Implements CoinPresolveAction.

Definition at line 56 of file CoinPresolveEmpty.hpp.

static const CoinPresolveAction* drop_empty_cols_action::presolve ( CoinPresolveMatrix ,
const int *  ecols,
int  necols,
const CoinPresolveAction  
)
static
static const CoinPresolveAction* drop_empty_cols_action::presolve ( CoinPresolveMatrix prob,
const CoinPresolveAction next 
)
static
void drop_empty_cols_action::postsolve ( CoinPostsolveMatrix prob) const
virtual

Apply the postsolve transformation for this particular presolve action.

Implements CoinPresolveAction.

Member Data Documentation

const int drop_empty_cols_action::nactions_
private

Definition at line 36 of file CoinPresolveEmpty.hpp.

const action* const drop_empty_cols_action::actions_
private

Definition at line 45 of file CoinPresolveEmpty.hpp.


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