# AbcPrimalColumnSteepest Class Reference

Primal Column Pivot Steepest Edge Algorithm Class. More...

`#include <AbcPrimalColumnSteepest.hpp>`

Inheritance diagram for AbcPrimalColumnSteepest:
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Collaboration diagram for AbcPrimalColumnSteepest:
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List of all members.

## Public Types
enum | Persistence { normal = 0x00, keep = 0x01 }
| enums for persistence More...
## Public Member Functions
Algorithmic methods
virtual int | pivotColumn (CoinPartitionedVector *updates, CoinPartitionedVector *spareRow2, CoinPartitionedVector *spareColumn1)
| Returns pivot column, -1 if none.
void | justDjs (CoinIndexedVector *updates, CoinIndexedVector *spareColumn1)
| Just update djs.
int | partialPricing (CoinIndexedVector *updates, int numberWanted, int numberLook)
| Update djs doing partial pricing (dantzig).
void | djsAndDevex (CoinIndexedVector *updates, CoinIndexedVector *spareRow2, CoinIndexedVector *spareColumn1)
| Update djs, weights for Devex using djs.
void | djsAndDevex2 (CoinIndexedVector *updates, CoinIndexedVector *spareColumn1)
| Update djs, weights for Devex using pivot row.
void | justDevex (CoinIndexedVector *updates, CoinIndexedVector *spareColumn1)
| Update weights for Devex.
int | doSteepestWork (CoinPartitionedVector *updates, CoinPartitionedVector *spareRow2, CoinPartitionedVector *spareColumn1, int type)
| Does steepest work type - 0 - just djs 1 - just steepest 2 - both using scaleFactor 3 - both using extra array.
virtual void | updateWeights (CoinIndexedVector *input)
| Updates weights - part 1 - also checks accuracy.
void | checkAccuracy (int sequence, double relativeTolerance, CoinIndexedVector *rowArray1)
| Checks accuracy - just for debug.
void | initializeWeights ()
| Initialize weights.
virtual void | saveWeights (AbcSimplex *model, int mode)
| Save weights - this may initialize weights as well mode is - 1) before factorization 2) after factorization 3) just redo infeasibilities 4) restore weights 5) at end of values pass (so need initialization).
virtual void | unrollWeights ()
| Gets rid of last update.
virtual void | clearArrays ()
| Gets rid of all arrays.
virtual bool | looksOptimal () const
| Returns true if would not find any column.
virtual void | maximumPivotsChanged ()
| Called when maximum pivots changes.
gets and sets
int | mode () const
| Mode.
Constructors and destructors
| AbcPrimalColumnSteepest (int mode=3)
| Default Constructor 0 is exact devex, 1 full steepest, 2 is partial exact devex 3 switches between 0 and 2 depending on factorization 4 starts as partial dantzig/devex but then may switch between 0 and 2.
| AbcPrimalColumnSteepest (const AbcPrimalColumnSteepest &rhs)
| Copy constructor.
AbcPrimalColumnSteepest & | operator= (const AbcPrimalColumnSteepest &rhs)
| Assignment operator.
virtual | ~AbcPrimalColumnSteepest ()
| Destructor.
virtual AbcPrimalColumnPivot * | clone (bool copyData=true) const
| Clone.
Private functions to deal with devex
bool | reference (int i) const
| reference would be faster using AbcSimplex's status_, but I prefer to keep modularity.
void | setReference (int i, bool trueFalse)
| reference would be faster using AbcSimplex's status_, but I prefer to keep modularity.
void | setPersistence (Persistence life)
| Set/ get persistence.
Persistence | persistence () const
| reference would be faster using AbcSimplex's status_, but I prefer to keep modularity.
## Private Attributes
Private member data
double | devex_
| weight array
double * | weights_
| weight array
CoinIndexedVector * | infeasible_
| square of infeasibility array (just for infeasible columns)
CoinIndexedVector * | alternateWeights_
| alternate weight array (so we can unroll)
double * | savedWeights_
| save weight array (so we can use checkpoint)
unsigned int * | reference_
| weight array
int | state_
| Status 0) Normal -1) Needs initialization 1) Weights are stored by sequence number.
int | mode_
| 0 is exact devex, 1 full steepest, 2 is partial exact devex 3 switches between 0 and 2 depending on factorization 4 starts as partial dantzig/devex but then may switch between 0 and 2.
Persistence | persistence_
| Life of weights.
int | numberSwitched_
| Number of times switched from partial dantzig to 0/2.
int | pivotSequence_
| weight array
int | savedPivotSequence_
| weight array
int | savedSequenceOut_
| weight array
int | lastRectified_
| weight array
int | sizeFactorization_
| weight array

## Detailed Description

Primal Column Pivot Steepest Edge Algorithm Class.

See Forrest-Goldfarb paper for algorithm

Definition at line 23 of file AbcPrimalColumnSteepest.hpp.

## Member Enumeration Documentation

enum AbcPrimalColumnSteepest::Persistence

enums for persistence

Enumerator:

  normal |
  keep |

Definition at line 108 of file AbcPrimalColumnSteepest.hpp.

## Constructor & Destructor Documentation

AbcPrimalColumnSteepest::AbcPrimalColumnSteepest | ( | int | mode = `3` | ) |

Default Constructor 0 is exact devex, 1 full steepest, 2 is partial exact devex 3 switches between 0 and 2 depending on factorization 4 starts as partial dantzig/devex but then may switch between 0 and 2.

By partial exact devex is meant that the weights are updated as normal but only part of the nonbasic variables are scanned. This can be faster on very easy problems.

AbcPrimalColumnSteepest::AbcPrimalColumnSteepest | ( | const AbcPrimalColumnSteepest & | rhs | ) |

Copy constructor.

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

Destructor.

## Member Function Documentation

virtual int AbcPrimalColumnSteepest::pivotColumn | ( | CoinPartitionedVector * | updates,
|  | CoinPartitionedVector * | spareRow2,
|  | CoinPartitionedVector * | spareColumn1 |
| ) |  |  | `[virtual]`

Returns pivot column, -1 if none.

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 Parts of operation split out into separate functions for profiling and speed

Implements AbcPrimalColumnPivot.

void AbcPrimalColumnSteepest::justDjs | ( | CoinIndexedVector * | updates,
|  | CoinIndexedVector * | spareColumn1 |
| ) |  |  |

Just update djs.

int AbcPrimalColumnSteepest::partialPricing | ( | CoinIndexedVector * | updates,
|  | int | numberWanted,
|  | int | numberLook |
| ) |  |  |

Update djs doing partial pricing (dantzig).

void AbcPrimalColumnSteepest::djsAndDevex | ( | CoinIndexedVector * | updates,
|  | CoinIndexedVector * | spareRow2,
|  | CoinIndexedVector * | spareColumn1 |
| ) |  |  |

Update djs, weights for Devex using djs.

void AbcPrimalColumnSteepest::djsAndDevex2 | ( | CoinIndexedVector * | updates,
|  | CoinIndexedVector * | spareColumn1 |
| ) |  |  |

Update djs, weights for Devex using pivot row.

void AbcPrimalColumnSteepest::justDevex | ( | CoinIndexedVector * | updates,
|  | CoinIndexedVector * | spareColumn1 |
| ) |  |  |

Update weights for Devex.

int AbcPrimalColumnSteepest::doSteepestWork | ( | CoinPartitionedVector * | updates,
|  | CoinPartitionedVector * | spareRow2,
|  | CoinPartitionedVector * | spareColumn1,
|  | int | type |
| ) |  |  |

Does steepest work type - 0 - just djs 1 - just steepest 2 - both using scaleFactor 3 - both using extra array.

virtual void AbcPrimalColumnSteepest::updateWeights | ( | CoinIndexedVector * | input | ) | `[virtual]`

Updates weights - part 1 - also checks accuracy.

Reimplemented from AbcPrimalColumnPivot.

void AbcPrimalColumnSteepest::checkAccuracy | ( | int | sequence,
|  | double | relativeTolerance,
|  | CoinIndexedVector * | rowArray1 |
| ) |  |  |

Checks accuracy - just for debug.

void AbcPrimalColumnSteepest::initializeWeights | ( |  | ) |

Initialize weights.

virtual void AbcPrimalColumnSteepest::saveWeights | ( | AbcSimplex * | model,
|  | int | mode |
| ) |  |  | `[virtual]`

Save weights - this may initialize weights as well mode is - 1) before factorization 2) after factorization 3) just redo infeasibilities 4) restore weights 5) at end of values pass (so need initialization).

Implements AbcPrimalColumnPivot.

virtual void AbcPrimalColumnSteepest::unrollWeights | ( |  | ) | `[virtual]`

Gets rid of last update.

virtual void AbcPrimalColumnSteepest::clearArrays | ( |  | ) | `[virtual]`

Gets rid of all arrays.

Reimplemented from AbcPrimalColumnPivot.

virtual bool AbcPrimalColumnSteepest::looksOptimal | ( |  | ) | const`[virtual]`

Returns true if would not find any column.

Reimplemented from AbcPrimalColumnPivot.

virtual void AbcPrimalColumnSteepest::maximumPivotsChanged | ( |  | ) | `[virtual]`

Called when maximum pivots changes.

Reimplemented from AbcPrimalColumnPivot.

int AbcPrimalColumnSteepest::mode | ( |  | ) | const`[inline]`

Mode.

Definition at line 101 of file AbcPrimalColumnSteepest.hpp.

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

Assignment operator.

Reimplemented from AbcPrimalColumnPivot.

virtual AbcPrimalColumnPivot* AbcPrimalColumnSteepest::clone | ( | bool | copyData = `true` | ) | const`[virtual]`

Clone.

Implements AbcPrimalColumnPivot.

bool AbcPrimalColumnSteepest::reference | ( | int | i | ) | const`[inline]`

reference would be faster using AbcSimplex's status_, but I prefer to keep modularity.

Definition at line 143 of file AbcPrimalColumnSteepest.hpp.

void AbcPrimalColumnSteepest::setReference | ( | int | i,
|  | bool | trueFalse |
| ) |  |  | `[inline]`

reference would be faster using AbcSimplex's status_, but I prefer to keep modularity.

Definition at line 146 of file AbcPrimalColumnSteepest.hpp.

void AbcPrimalColumnSteepest::setPersistence | ( | Persistence | life | ) | `[inline]`

Set/ get persistence.

Definition at line 155 of file AbcPrimalColumnSteepest.hpp.

Persistence AbcPrimalColumnSteepest::persistence | ( |  | ) | const`[inline]`

reference would be faster using AbcSimplex's status_, but I prefer to keep modularity.

Definition at line 158 of file AbcPrimalColumnSteepest.hpp.

## Member Data Documentation

double AbcPrimalColumnSteepest::devex_`[private]`

weight array

Definition at line 168 of file AbcPrimalColumnSteepest.hpp.

double* AbcPrimalColumnSteepest::weights_`[private]`

weight array

Definition at line 170 of file AbcPrimalColumnSteepest.hpp.

CoinIndexedVector* AbcPrimalColumnSteepest::infeasible_`[private]`

square of infeasibility array (just for infeasible columns)

Definition at line 172 of file AbcPrimalColumnSteepest.hpp.

CoinIndexedVector* AbcPrimalColumnSteepest::alternateWeights_`[private]`

alternate weight array (so we can unroll)

Definition at line 174 of file AbcPrimalColumnSteepest.hpp.

double* AbcPrimalColumnSteepest::savedWeights_`[private]`

save weight array (so we can use checkpoint)

Definition at line 176 of file AbcPrimalColumnSteepest.hpp.

unsigned int* AbcPrimalColumnSteepest::reference_`[private]`

weight array

Definition at line 178 of file AbcPrimalColumnSteepest.hpp.

int AbcPrimalColumnSteepest::state_`[private]`

Status 0) Normal -1) Needs initialization 1) Weights are stored by sequence number.

Definition at line 184 of file AbcPrimalColumnSteepest.hpp.

int AbcPrimalColumnSteepest::mode_`[private]`

0 is exact devex, 1 full steepest, 2 is partial exact devex 3 switches between 0 and 2 depending on factorization 4 starts as partial dantzig/devex but then may switch between 0 and 2.

5 is always partial dantzig By partial exact devex is meant that the weights are updated as normal but only part of the nonbasic variables are scanned. This can be faster on very easy problems.

New dubious option is >=10 which does mini-sprint

Definition at line 197 of file AbcPrimalColumnSteepest.hpp.

Persistence AbcPrimalColumnSteepest::persistence_`[private]`

Life of weights.

Definition at line 199 of file AbcPrimalColumnSteepest.hpp.

int AbcPrimalColumnSteepest::numberSwitched_`[private]`

Number of times switched from partial dantzig to 0/2.

Definition at line 201 of file AbcPrimalColumnSteepest.hpp.

int AbcPrimalColumnSteepest::pivotSequence_`[private]`

weight array

Definition at line 203 of file AbcPrimalColumnSteepest.hpp.

int AbcPrimalColumnSteepest::savedPivotSequence_`[private]`

weight array

Definition at line 205 of file AbcPrimalColumnSteepest.hpp.

int AbcPrimalColumnSteepest::savedSequenceOut_`[private]`

weight array

Definition at line 207 of file AbcPrimalColumnSteepest.hpp.

int AbcPrimalColumnSteepest::lastRectified_`[private]`

weight array

Definition at line 209 of file AbcPrimalColumnSteepest.hpp.

int AbcPrimalColumnSteepest::sizeFactorization_`[private]`

weight array

Definition at line 211 of file AbcPrimalColumnSteepest.hpp.

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

- /home/coin/svn-release/Alps-1.5.0/Clp/src/AbcPrimalColumnSteepest.hpp