CoinUtils  2.10.13
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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:

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 ~implied_free_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 CoinPresolveAction *next, int &fillLevel)
 
- Static Public Member Functions inherited from CoinPresolveAction
static void throwCoinError (const char *error, const char *ps_routine)
 Stub routine to throw exceptions. More...
 

Additional Inherited Members

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

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.

A similar transform for the case where the variable is not a natural column singleton is handled by subst_constraint_action.

Definition at line 29 of file CoinPresolveImpliedFree.hpp.

Constructor & Destructor Documentation

virtual implied_free_action::~implied_free_action ( )
virtual

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: