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# OsiObject Class Reference

Abstract base class for `objects'. More...

`#include <OsiBranchingObject.hpp>`

Inheritance diagram for OsiObject:

[legend]
List of all members.

## Public Member Functions
| OsiObject ()
| Default Constructor.
| OsiObject (const OsiObject &)
| Copy constructor.
OsiObject & | operator= (const OsiObject &rhs)
| Assignment operator.
virtual OsiObject * | clone () const =0
| Clone.
virtual | ~OsiObject ()
| Destructor.
double | infeasibility (const OsiSolverInterface *solver, int &whichWay) const
| Infeasibility of the object.
virtual double | infeasibility (const OsiBranchingInformation *info, int &whichWay) const =0
virtual double | checkInfeasibility (const OsiBranchingInformation *info) const
virtual double | feasibleRegion (OsiSolverInterface *solver) const
| For the variable(s) referenced by the object, look at the current solution and set bounds to match the solution.
virtual double | feasibleRegion (OsiSolverInterface *solver, const OsiBranchingInformation *info) const =0
| For the variable(s) referenced by the object, look at the current solution and set bounds to match the solution.
virtual OsiBranchingObject * | createBranch (OsiSolverInterface *, const OsiBranchingInformation *, int) const
| Create a branching object and indicate which way to branch first.
virtual bool | canDoHeuristics () const
| Return true if object can take part in normal heuristics.
virtual bool | canMoveToNearest () const
| Return true if object can take part in move to nearest heuristic.
virtual int | columnNumber () const
| Column number if single column object -1 otherwise, Used by heuristics.
int | priority () const
| Return Priority - note 1 is highest priority.
void | setPriority (int priority)
| Set priority.
virtual bool | boundBranch () const
| Return true if branch should only bound variables.
virtual bool | canHandleShadowPrices () const
| Return true if knows how to deal with Pseudo Shadow Prices.
int | numberWays () const
| Return maximum number of ways branch may have.
void | setNumberWays (int numberWays)
| Set maximum number of ways branch may have.
void | setWhichWay (int way)
| Return preferred way to branch.
int | whichWay () const
| Return current preferred way to branch.
virtual int | preferredWay () const
| Get pre-emptive preferred way of branching - -1 off, 0 down, 1 up (for 2-way).
double | infeasibility () const
| Return infeasibility.
virtual double | upEstimate () const
| Return "up" estimate (default 1.0e-5).
virtual double | downEstimate () const
| Return "down" estimate (default 1.0e-5).
virtual void | resetBounds (const OsiSolverInterface *)
| Reset variable bounds to their original values.
virtual void | resetSequenceEtc (int, const int *)
| Change column numbers after preprocessing.
virtual void | updateBefore (const OsiObject *)
| Updates stuff like pseudocosts before threads.
virtual void | updateAfter (const OsiObject *, const OsiObject *)
| Updates stuff like pseudocosts after threads finished.
## Protected Attributes
double | infeasibility_
| Computed infeasibility.
short | whichWay_
| Computed preferred way to branch.
short | numberWays_
| Maximum number of ways on branch.
int | priority_
| Priority.

## Detailed Description

Abstract base class for `objects'.

The branching model used in Osi is based on the idea of an object. In the abstract, an object is something that has a feasible region, can be evaluated for infeasibility, can be branched on (i.e., there's some constructive action to be taken to move toward feasibility), and allows comparison of the effect of branching.

This class (OsiObject) is the base class for an object. To round out the branching model, the class OsiBranchingObject describes how to perform a branch, and the class OsiBranchDecision describes how to compare two OsiBranchingObjects.

To create a new type of object you need to provide three methods: infeasibility(), feasibleRegion(), and createBranch(), described below.

This base class is primarily virtual to allow for any form of structure. Any form of discontinuity is allowed.

As there is an overhead in getting information from solvers and because other useful information is available there is also an OsiBranchingInformation class which can contain pointers to information. If used it must at minimum contain pointers to current value of objective, maximum allowed objective and pointers to arrays for bounds and solution and direction of optimization. Also integer and primal tolerance.

Classes which inherit might have other information such as depth, number of solutions, pseudo-shadow prices etc etc. May be easier just to throw in here - as I keep doing

Definition at line 56 of file OsiBranchingObject.hpp.

## Constructor & Destructor Documentation

OsiObject::OsiObject | ( |  | ) |

Default Constructor.

OsiObject::OsiObject | ( | const OsiObject & |  | ) |

Copy constructor.

virtual OsiObject::~OsiObject | ( |  | ) | `[virtual]`

Destructor.

## Member Function Documentation

OsiObject& OsiObject::operator= | ( | const OsiObject & | rhs | ) |

Assignment operator.

virtual OsiObject* OsiObject::clone | ( |  | ) | const`[pure virtual]`

Clone.

Implemented in OsiSimpleInteger, OsiSOS, and OsiLotsize.

double OsiObject::infeasibility | ( | const OsiSolverInterface * | solver,
|  | int & | whichWay |
| ) |  |  | const

Infeasibility of the object.

This is some measure of the infeasibility of the object. 0.0 indicates that the object is satisfied.

The preferred branching direction is returned in whichWay, where for normal two-way branching 0 is down, 1 is up

This is used to prepare for strong branching but should also think of case when no strong branching

The object may also compute an estimate of cost of going "up" or "down". This will probably be based on pseudo-cost ideas

This should also set mutable infeasibility_ and whichWay_ This is for instant re-use for speed

Default for this just calls infeasibility with OsiBranchingInformation NOTE - Convention says that an infeasibility of COIN_DBL_MAX means object has worked out it can't be satisfied!

virtual double OsiObject::infeasibility | ( | const OsiBranchingInformation * | info,
|  | int & | whichWay |
| ) |  |  | const`[pure virtual]`

Implemented in OsiSimpleInteger, OsiSOS, and OsiLotsize.

virtual double OsiObject::checkInfeasibility | ( | const OsiBranchingInformation * | info | ) | const`[virtual]`

virtual double OsiObject::feasibleRegion | ( | OsiSolverInterface * | solver | ) | const`[virtual]`

For the variable(s) referenced by the object, look at the current solution and set bounds to match the solution.

Returns measure of how much it had to move solution to make feasible

virtual double OsiObject::feasibleRegion | ( | OsiSolverInterface * | solver,
|  | const OsiBranchingInformation * | info |
| ) |  |  | const`[pure virtual]`

For the variable(s) referenced by the object, look at the current solution and set bounds to match the solution.

Returns measure of how much it had to move solution to make feasible Faster version

Implemented in OsiSimpleInteger, OsiSOS, and OsiLotsize.

virtual OsiBranchingObject* OsiObject::createBranch | ( | OsiSolverInterface * | ,
|  | const OsiBranchingInformation * | ,
|  | int |  |
| ) |  |  | const`[inline, virtual]`

Create a branching object and indicate which way to branch first.

The branching object has to know how to create branches (fix variables, etc.)

Reimplemented in OsiSimpleInteger, OsiSOS, and OsiLotsize.

Definition at line 119 of file OsiBranchingObject.hpp.

virtual bool OsiObject::canDoHeuristics | ( |  | ) | const`[inline, virtual]`

Return true if object can take part in normal heuristics.

Reimplemented in OsiSOS, and OsiLotsize.

Definition at line 125 of file OsiBranchingObject.hpp.

virtual bool OsiObject::canMoveToNearest | ( |  | ) | const`[inline, virtual]`

Return true if object can take part in move to nearest heuristic.

Definition at line 129 of file OsiBranchingObject.hpp.

virtual int OsiObject::columnNumber | ( |  | ) | const`[virtual]`

Column number if single column object -1 otherwise, Used by heuristics.

Reimplemented in OsiSimpleInteger, and OsiLotsize.

int OsiObject::priority | ( |  | ) | const`[inline]`

Return Priority - note 1 is highest priority.

Definition at line 136 of file OsiBranchingObject.hpp.

References priority_.

void OsiObject::setPriority | ( | int | priority | ) | `[inline]`

Set priority.

Definition at line 139 of file OsiBranchingObject.hpp.

References priority_.

virtual bool OsiObject::boundBranch | ( |  | ) | const`[inline, virtual]`

Return true if branch should only bound variables.

Definition at line 143 of file OsiBranchingObject.hpp.

virtual bool OsiObject::canHandleShadowPrices | ( |  | ) | const`[inline, virtual]`

Return true if knows how to deal with Pseudo Shadow Prices.

Reimplemented in OsiSimpleInteger, OsiSOS, and OsiLotsize.

Definition at line 146 of file OsiBranchingObject.hpp.

int OsiObject::numberWays | ( |  | ) | const`[inline]`

Return maximum number of ways branch may have.

Definition at line 149 of file OsiBranchingObject.hpp.

References numberWays_.

void OsiObject::setNumberWays | ( | int | numberWays | ) | `[inline]`

Set maximum number of ways branch may have.

Definition at line 152 of file OsiBranchingObject.hpp.

References numberWays_.

void OsiObject::setWhichWay | ( | int | way | ) | `[inline]`

Return preferred way to branch.

If two then way=0 means down and 1 means up, otherwise way points to preferred branch

Definition at line 158 of file OsiBranchingObject.hpp.

References whichWay_.

int OsiObject::whichWay | ( |  | ) | const`[inline]`

Return current preferred way to branch.

If two then way=0 means down and 1 means up, otherwise way points to preferred branch

Definition at line 164 of file OsiBranchingObject.hpp.

References whichWay_.

virtual int OsiObject::preferredWay | ( |  | ) | const`[inline, virtual]`

Get pre-emptive preferred way of branching - -1 off, 0 down, 1 up (for 2-way).

Reimplemented in OsiObject2.

Definition at line 167 of file OsiBranchingObject.hpp.

double OsiObject::infeasibility | ( |  | ) | const`[inline]`

Return infeasibility.

Definition at line 170 of file OsiBranchingObject.hpp.

References infeasibility_.

virtual double OsiObject::upEstimate | ( |  | ) | const`[virtual]`

Return "up" estimate (default 1.0e-5).

Reimplemented in OsiSimpleInteger, OsiSOS, and OsiLotsize.

virtual double OsiObject::downEstimate | ( |  | ) | const`[virtual]`

Return "down" estimate (default 1.0e-5).

Reimplemented in OsiSimpleInteger, OsiSOS, and OsiLotsize.

virtual void OsiObject::resetBounds | ( | const OsiSolverInterface * |  | ) | `[inline, virtual]`

Reset variable bounds to their original values.

Bounds may be tightened, so it may be good to be able to reset them to their original values.

Reimplemented in OsiSimpleInteger, and OsiLotsize.

Definition at line 180 of file OsiBranchingObject.hpp.

virtual void OsiObject::resetSequenceEtc | ( | int | ,
|  | const int * |  |
| ) |  |  | `[inline, virtual]`

Change column numbers after preprocessing.

Reimplemented in OsiSimpleInteger, OsiSOS, and OsiLotsize.

Definition at line 183 of file OsiBranchingObject.hpp.

virtual void OsiObject::updateBefore | ( | const OsiObject * |  | ) | `[inline, virtual]`

Updates stuff like pseudocosts before threads.

Definition at line 185 of file OsiBranchingObject.hpp.

virtual void OsiObject::updateAfter | ( | const OsiObject * | ,
|  | const OsiObject * |  |
| ) |  |  | `[inline, virtual]`

Updates stuff like pseudocosts after threads finished.

Definition at line 187 of file OsiBranchingObject.hpp.

## Member Data Documentation

double OsiObject::infeasibility_`[mutable, protected]`

Computed infeasibility.

Definition at line 193 of file OsiBranchingObject.hpp.

Referenced by infeasibility().

short OsiObject::whichWay_`[mutable, protected]`

Computed preferred way to branch.

Definition at line 195 of file OsiBranchingObject.hpp.

Referenced by setWhichWay(), and whichWay().

short OsiObject::numberWays_`[protected]`

Maximum number of ways on branch.

Definition at line 197 of file OsiBranchingObject.hpp.

Referenced by numberWays(), and setNumberWays().

int OsiObject::priority_`[protected]`

Priority.

Definition at line 199 of file OsiBranchingObject.hpp.

Referenced by priority(), and setPriority().

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

- /home/coin/SVN-release/Alps-1.3.0/Osi/src/Osi/OsiBranchingObject.hpp