# implied_free_action Class Reference

Detect and process implied free variables. More...

`#include <CoinPresolveImpliedFree.hpp>`

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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.
virtual | ~implied_free_action ()
## Static Public Member Functions
static const CoinPresolveAction * | presolve (CoinPresolveMatrix *prob, const CoinPresolveAction *next, int &fillLevel)
## Private Member Functions
| implied_free_action (int nactions, const action *actions, const CoinPresolveAction *next)
## Private Attributes
const int | nactions_
const action *const | actions_

## 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

implied_free_action::implied_free_action | ( | int | nactions,
|  | const action * | actions,
|  | const CoinPresolveAction * | next |
| ) |  |  | `[inline, private]`

Definition at line 42 of file CoinPresolveImpliedFree.hpp.

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.

## Member Data Documentation

const int implied_free_action::nactions_`[private]`

Definition at line 39 of file CoinPresolveImpliedFree.hpp.

const action* const implied_free_action::actions_`[private]`

Definition at line 40 of file CoinPresolveImpliedFree.hpp.

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

- /home/coin/svn-release/Alps-1.5.2/CoinUtils/src/CoinPresolveImpliedFree.hpp