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implied_free_action Class Reference

Detect and process implied free variables. More...

#include <CoinPresolveImpliedFree.hpp>

Inheritance diagram for implied_free_action:
Collaboration diagram for implied_free_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.
 ~implied_free_action ()

Static Public Member Functions

static const CoinPresolveActionpresolve (CoinPresolveMatrix *prob, const CoinPresolveAction *next, int &fillLevel)

Detailed Description

Detect and process implied free variables.

Consider a singleton variable x (i.e., a variable involved in only one constraint). Suppose that the bounds on that constraint, combined with the bounds on the other variables involved in the constraint, are such that even the worst case values of the other variables still imply bounds for x which are tighter than the variable's original bounds. Since x can never reach its upper or lower bounds, it is an implied free variable. Both x and the constraint can be deleted from the problem.

The transform also handles more complicated variations, where x is not a singleton.

Definition at line 29 of file CoinPresolveImpliedFree.hpp.


Constructor & Destructor Documentation

implied_free_action::~implied_free_action ( )

Member Function Documentation

const char* implied_free_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* implied_free_action::presolve ( CoinPresolveMatrix prob,
const CoinPresolveAction next,
int &  fillLevel 
) [static]
void implied_free_action::postsolve ( CoinPostsolveMatrix prob) const [virtual]

Apply the postsolve transformation for this particular presolve action.

Implements CoinPresolveAction.


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