dupcol_action Class Reference

Detect and remove duplicate columns. More...

#include <CoinPresolveDupcol.hpp>

Inheritance diagram for dupcol_action:

Collaboration diagram for dupcol_action:

Classes
struct	action

Public Member Functions
const char *	name () const
	Construct a postsolve object and add it to the transformation list.
void	postsolve (CoinPostsolveMatrix *prob) const
	Apply the postsolve transformation for this particular presolve action.
virtual	~dupcol_action ()
Public Member Functions inherited from CoinPresolveAction
virtual	~CoinPresolveAction ()
	Virtual destructor.

Static Public Member Functions
static const CoinPresolveAction *	presolve (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.

Private Member Functions
	dupcol_action ()
	dupcol_action (const dupcol_action &rhs)
dupcol_action &	operator= (const dupcol_action &rhs)
	dupcol_action (int nactions, const action *actions, const CoinPresolveAction *next)

Private Attributes
const int	nactions_
const action *const	actions_

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

Detailed Description

Detect and remove duplicate columns.

The general technique is to sum the coefficients a_(*,j) of each column. Columns with identical sums are duplicates. The obvious problem is that, e.g., [1 0 1 0] and [0 1 0 1] both add to 2. To minimize the chances of false positives, the coefficients of each row are multipled by a random number r_i, so that we sum r_i*a_ij.

Candidate columns are checked to confirm they are identical. Where the columns have the same objective coefficient, the two are combined. If the columns have different objective coefficients, complications ensue. In order to remove the duplicate, it must be possible to fix the variable at a bound.

Definition at line 32 of file CoinPresolveDupcol.hpp.

Constructor & Destructor Documentation

dupcol_action() [1/3]

dupcol_action::dupcol_action ( )

private

dupcol_action() [2/3]

dupcol_action::dupcol_action ( const dupcol_action & rhs )

private

dupcol_action() [3/3]

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

inlineprivate

Definition at line 53 of file CoinPresolveDupcol.hpp.

~dupcol_action()

virtual dupcol_action::~dupcol_action ( )

virtual

Member Function Documentation

operator=()

dupcol_action & dupcol_action::operator= ( const dupcol_action & rhs )

private

name()

const char * dupcol_action::name ( ) const

virtual

Construct a postsolve object and add it to the transformation list.

This is an `add to head' operation. This object will point to the one passed as the parameter. */ CoinPresolveAction(const CoinPresolveAction *next) : next(next) { } modify next (when building rather than passing) inline void setNext(const CoinPresolveAction *nextAction) { next = nextAction; }

/*! A name for debug printing.

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

Implements CoinPresolveAction.

presolve()

const CoinPresolveAction * dupcol_action::presolve ( CoinPresolveMatrix * prob, const CoinPresolveAction * next )

static

postsolve()

void dupcol_action::postsolve ( CoinPostsolveMatrix * prob ) const

virtual

Apply the postsolve transformation for this particular presolve action.

Implements CoinPresolveAction.

Member Data Documentation

nactions_

const int dupcol_action::nactions_

private

Definition at line 49 of file CoinPresolveDupcol.hpp.

actions_

const action* const dupcol_action::actions_

private

Definition at line 51 of file CoinPresolveDupcol.hpp.

---

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

• /builddir/build/BUILD/coin-or-CoinUtils-2.11.12-build/CoinUtils-releases-2.11.12/CoinUtils/src/CoinPresolveDupcol.hpp