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make_fixed_action Class Reference

Fix a variable at a specified bound. More...

#include <CoinPresolveFixed.hpp>

+ Inheritance diagram for make_fixed_action:
+ Collaboration diagram for make_fixed_action:

Classes

struct  action
 Structure to preserve the bound overwritten when fixing a variable. More...
 

Public Member Functions

const char * name () const
 Returns string "make_fixed_action". More...
 
void postsolve (CoinPostsolveMatrix *prob) const
 Postsolve (unfix variables) More...
 
virtual ~make_fixed_action ()
 Destructor. More...
 
- 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, int *fcols, int nfcols, bool fix_to_lower, const CoinPresolveAction *next)
 Perform actions to fix variables and return postsolve object. More...
 
- 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

 make_fixed_action (int nactions, const action *actions, bool fix_to_lower, const remove_fixed_action *faction, const CoinPresolveAction *next)
 Constructor. More...
 

Private Attributes

int nactions_
 Number of preserved bounds. More...
 
const actionactions_
 Vector of preserved bounds, one for each variable fixed in this object. More...
 
const bool fix_to_lower_
 True to fix at lower bound, false to fix at upper bound. More...
 
const remove_fixed_actionfaction_
 The postsolve object with the information required to repopulate the fixed columns. More...
 

Related Functions

(Note that these are not member functions.)

const CoinPresolveActionmake_fixed (CoinPresolveMatrix *prob, const CoinPresolveAction *next)
 Scan variables and fix any with equal bounds. More...
 
void transferCosts (CoinPresolveMatrix *prob)
 Transfer costs from singleton variables. More...
 

Additional Inherited Members

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

Detailed Description

Fix a variable at a specified bound.

Implements the action of fixing a variable by forcing both bounds to the same value and forcing the value of the variable to match.

If the bounds are already equal, and the value of the variable is already correct, consider remove_fixed_action.

Definition at line 95 of file CoinPresolveFixed.hpp.

Constructor & Destructor Documentation

make_fixed_action::make_fixed_action ( int  nactions,
const action actions,
bool  fix_to_lower,
const remove_fixed_action faction,
const CoinPresolveAction next 
)
inlineprivate

Constructor.

Definition at line 120 of file CoinPresolveFixed.hpp.

virtual make_fixed_action::~make_fixed_action ( )
inlinevirtual

Destructor.

Definition at line 153 of file CoinPresolveFixed.hpp.

Member Function Documentation

const char* make_fixed_action::name ( ) const
virtual

Returns string "make_fixed_action".

Implements CoinPresolveAction.

static const CoinPresolveAction* make_fixed_action::presolve ( CoinPresolveMatrix prob,
int *  fcols,
int  nfcols,
bool  fix_to_lower,
const CoinPresolveAction next 
)
static

Perform actions to fix variables and return postsolve object.

For each specified variable (nfcols, fcols), fix the variable to the specified bound (fix_to_lower) by setting the variable's bounds to be equal in prob. Create a postsolve object, link it at the head of the list of postsolve objects (next), and return the object.

void make_fixed_action::postsolve ( CoinPostsolveMatrix prob) const
virtual

Postsolve (unfix variables)

Back out the variables fixed by the presolve side of this object.

Implements CoinPresolveAction.

Friends And Related Function Documentation

const CoinPresolveAction * make_fixed ( CoinPresolveMatrix prob,
const CoinPresolveAction next 
)
related

Scan variables and fix any with equal bounds.

A front end to collect a list of columns with equal bounds and hand them to make_fixed_action::presolve() for processing.

void transferCosts ( CoinPresolveMatrix prob)
related

Transfer costs from singleton variables.

Transfers costs from singleton variables in equalities onto the other variables. Will also transfer costs from one integer variable to other integer variables with zero cost if there's a net gain in integer variables with non-zero cost.

The relation to make_fixed_action is tenuous, but this transform should be attempted before the initial round of variable fixing.

Member Data Documentation

int make_fixed_action::nactions_
private

Number of preserved bounds.

Definition at line 104 of file CoinPresolveFixed.hpp.

const action* make_fixed_action::actions_
private

Vector of preserved bounds, one for each variable fixed in this object.

Definition at line 106 of file CoinPresolveFixed.hpp.

const bool make_fixed_action::fix_to_lower_
private

True to fix at lower bound, false to fix at upper bound.

Note that this applies to all variables fixed in this object.

Definition at line 112 of file CoinPresolveFixed.hpp.

const remove_fixed_action* make_fixed_action::faction_
private

The postsolve object with the information required to repopulate the fixed columns.

Definition at line 117 of file CoinPresolveFixed.hpp.


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