Primal Column Pivot Abstract Base Class. More...
#include <ClpPrimalColumnPivot.hpp>
Public Member Functions | |
Algorithmic methods | |
virtual int | pivotColumn (CoinIndexedVector *updates, CoinIndexedVector *spareRow1, CoinIndexedVector *spareRow2, CoinIndexedVector *spareColumn1, CoinIndexedVector *spareColumn2)=0 |
Returns pivot column, -1 if none. | |
virtual void | updateWeights (CoinIndexedVector *input) |
Updates weights - part 1 (may be empty) | |
virtual void | saveWeights (ClpSimplex *model, int mode)=0 |
Saves any weights round factorization as pivot rows may change Will be empty unless steepest edge (will save model) May also recompute infeasibility stuff 1) before factorization 2) after good factorization (if weights empty may initialize) 3) after something happened but no factorization (e.g. | |
virtual int | pivotRow (double &way) |
Signals pivot row choice: | |
virtual void | clearArrays () |
Gets rid of all arrays (may be empty) | |
virtual bool | looksOptimal () const |
Returns true if would not find any column. | |
virtual void | setLooksOptimal (bool flag) |
Sets optimality flag (for advanced use) | |
Constructors and destructors | |
ClpPrimalColumnPivot () | |
Default Constructor. | |
ClpPrimalColumnPivot (const ClpPrimalColumnPivot &) | |
Copy constructor. | |
ClpPrimalColumnPivot & | operator= (const ClpPrimalColumnPivot &rhs) |
Assignment operator. | |
virtual | ~ClpPrimalColumnPivot () |
Destructor. | |
virtual ClpPrimalColumnPivot * | clone (bool copyData=true) const =0 |
Clone. | |
Other | |
ClpSimplex * | model () |
Returns model. | |
void | setModel (ClpSimplex *newmodel) |
Sets model. | |
int | type () |
Returns type (above 63 is extra information) | |
virtual int | numberSprintColumns (int &numberIterations) const |
Returns number of extra columns for sprint algorithm - 0 means off. | |
virtual void | switchOffSprint () |
Switch off sprint idea. | |
virtual void | maximumPivotsChanged () |
Called when maximum pivots changes. | |
Protected Attributes | |
Protected member data | |
ClpSimplex * | model_ |
Pointer to model. | |
int | type_ |
Type of column pivot algorithm. | |
bool | looksOptimal_ |
Says if looks optimal (normally computed) |
Primal Column Pivot Abstract Base Class.
Abstract Base Class for describing an interface to an algorithm to choose column pivot in primal simplex algorithm. For some algorithms e.g. Dantzig choice then some functions may be null. For Dantzig the only one of any importance is pivotColumn.
If you wish to inherit from this look at ClpPrimalColumnDantzig.cpp as that is simplest version.
Definition at line 23 of file ClpPrimalColumnPivot.hpp.
Default Constructor.
Copy constructor.
virtual ClpPrimalColumnPivot::~ClpPrimalColumnPivot | ( | ) | [virtual] |
Destructor.
virtual int ClpPrimalColumnPivot::pivotColumn | ( | CoinIndexedVector * | updates, |
CoinIndexedVector * | spareRow1, | ||
CoinIndexedVector * | spareRow2, | ||
CoinIndexedVector * | spareColumn1, | ||
CoinIndexedVector * | spareColumn2 | ||
) | [pure virtual] |
Returns pivot column, -1 if none.
Normally updates reduced costs using result of last iteration before selecting incoming column.
The Packed CoinIndexedVector updates has cost updates - for normal LP that is just +-weight where a feasibility changed. It also has reduced cost from last iteration in pivot row
Inside pivotColumn the pivotRow_ and reduced cost from last iteration are also used.
So in the simplest case i.e. feasible we compute the row of the tableau corresponding to last pivot and add a multiple of this to current reduced costs.
We can use other arrays to help updates
Implemented in ClpPrimalColumnSteepest, ClpPrimalColumnDantzig, and ClpPrimalQuadraticDantzig.
virtual void ClpPrimalColumnPivot::updateWeights | ( | CoinIndexedVector * | input | ) | [virtual] |
Updates weights - part 1 (may be empty)
Reimplemented in ClpPrimalColumnSteepest.
virtual void ClpPrimalColumnPivot::saveWeights | ( | ClpSimplex * | model, |
int | mode | ||
) | [pure virtual] |
Saves any weights round factorization as pivot rows may change Will be empty unless steepest edge (will save model) May also recompute infeasibility stuff 1) before factorization 2) after good factorization (if weights empty may initialize) 3) after something happened but no factorization (e.g.
check for infeasible) 4) as 2 but restore weights from previous snapshot 5) forces some initialization e.g. weights Also sets model
Implemented in ClpPrimalColumnSteepest, ClpPrimalColumnDantzig, and ClpPrimalQuadraticDantzig.
virtual int ClpPrimalColumnPivot::pivotRow | ( | double & | way | ) | [inline, virtual] |
Signals pivot row choice:
-2 (default) - use normal pivot row choice -1 to numberRows-1 - use this (will be checked) way should be -1 to go to lower bound, +1 to upper bound
Definition at line 74 of file ClpPrimalColumnPivot.hpp.
virtual void ClpPrimalColumnPivot::clearArrays | ( | ) | [virtual] |
Gets rid of all arrays (may be empty)
Reimplemented in ClpPrimalColumnSteepest.
virtual bool ClpPrimalColumnPivot::looksOptimal | ( | ) | const [inline, virtual] |
Returns true if would not find any column.
Reimplemented in ClpPrimalColumnSteepest.
Definition at line 81 of file ClpPrimalColumnPivot.hpp.
virtual void ClpPrimalColumnPivot::setLooksOptimal | ( | bool | flag | ) | [inline, virtual] |
Sets optimality flag (for advanced use)
Definition at line 85 of file ClpPrimalColumnPivot.hpp.
ClpPrimalColumnPivot& ClpPrimalColumnPivot::operator= | ( | const ClpPrimalColumnPivot & | rhs | ) |
Assignment operator.
virtual ClpPrimalColumnPivot* ClpPrimalColumnPivot::clone | ( | bool | copyData = true | ) | const [pure virtual] |
Clone.
Implemented in ClpPrimalColumnSteepest, ClpPrimalQuadraticDantzig, and ClpPrimalColumnDantzig.
ClpSimplex* ClpPrimalColumnPivot::model | ( | ) | [inline] |
Returns model.
Definition at line 113 of file ClpPrimalColumnPivot.hpp.
void ClpPrimalColumnPivot::setModel | ( | ClpSimplex * | newmodel | ) | [inline] |
Sets model.
Definition at line 117 of file ClpPrimalColumnPivot.hpp.
int ClpPrimalColumnPivot::type | ( | ) | [inline] |
Returns type (above 63 is extra information)
Definition at line 122 of file ClpPrimalColumnPivot.hpp.
virtual int ClpPrimalColumnPivot::numberSprintColumns | ( | int & | numberIterations | ) | const [virtual] |
Returns number of extra columns for sprint algorithm - 0 means off.
Also number of iterations before recompute
Reimplemented in ClpPrimalColumnSteepest.
virtual void ClpPrimalColumnPivot::switchOffSprint | ( | ) | [virtual] |
Switch off sprint idea.
Reimplemented in ClpPrimalColumnSteepest.
virtual void ClpPrimalColumnPivot::maximumPivotsChanged | ( | ) | [inline, virtual] |
Called when maximum pivots changes.
Reimplemented in ClpPrimalColumnSteepest.
Definition at line 133 of file ClpPrimalColumnPivot.hpp.
ClpSimplex* ClpPrimalColumnPivot::model_ [protected] |
Pointer to model.
Definition at line 143 of file ClpPrimalColumnPivot.hpp.
int ClpPrimalColumnPivot::type_ [protected] |
Type of column pivot algorithm.
Definition at line 145 of file ClpPrimalColumnPivot.hpp.
bool ClpPrimalColumnPivot::looksOptimal_ [protected] |
Says if looks optimal (normally computed)
Definition at line 147 of file ClpPrimalColumnPivot.hpp.