# AbcDualRowSteepest Class Reference

Dual Row Pivot Steepest Edge Algorithm Class. More...

`#include <AbcDualRowSteepest.hpp>`

Inheritance diagram for AbcDualRowSteepest:
[legend]
Collaboration diagram for AbcDualRowSteepest:
[legend]

List of all members.

## Public Types
enum | Persistence { normal = 0x00, keep = 0x01 }
| enums for persistence More...
## Public Member Functions
Algorithmic methods
virtual int | pivotRow ()
| Returns pivot row, -1 if none.
virtual double | updateWeights (CoinIndexedVector &input, CoinIndexedVector &updatedColumn)
| Updates weights and returns pivot alpha.
virtual double | updateWeights1 (CoinIndexedVector &input, CoinIndexedVector &updateColumn)
| Returns pivot row, -1 if none.
virtual void | updateWeightsOnly (CoinIndexedVector &input)
| Returns pivot row, -1 if none.
virtual void | updateWeights2 (CoinIndexedVector &input, CoinIndexedVector &updateColumn)
| Actually updates weights.
virtual void | updatePrimalSolution (CoinIndexedVector &input, double theta)
| Updates primal solution (and maybe list of candidates) Uses input vector which it deletes.
virtual void | updatePrimalSolutionAndWeights (CoinIndexedVector &weightsVector, CoinIndexedVector &updateColumn, double theta)
| Returns pivot row, -1 if none.
virtual void | saveWeights (AbcSimplex *model, int mode)
| Saves any weights round factorization as pivot rows may change 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 void | recomputeInfeasibilities ()
| Recompute infeasibilities.
virtual void | clearArrays ()
| Gets rid of all arrays.
virtual bool | looksOptimal () const
| Returns true if would not find any row.
Constructors and destructors
| AbcDualRowSteepest (int mode=3)
| Default Constructor 0 is uninitialized, 1 full, 2 is partial uninitialized, 3 starts as 2 but may switch to 1.
| AbcDualRowSteepest (const AbcDualRowSteepest &)
| Copy constructor.
AbcDualRowSteepest & | operator= (const AbcDualRowSteepest &rhs)
| Assignment operator.
void | fill (const AbcDualRowSteepest &rhs)
| Fill most values.
virtual | ~AbcDualRowSteepest ()
| Destructor.
virtual AbcDualRowPivot * | clone (bool copyData=true) const
| Clone.
gets and sets
int | mode () const
| Mode.
void | setPersistence (Persistence life)
| Set/ get persistence.
Persistence | persistence () const
| Mode.
CoinIndexedVector * | infeasible () const
| Infeasible vector.
CoinIndexedVector * | weights () const
| Weights vector.
AbcSimplex * | model () const
| Model.
## Private Attributes
Private member data
norm saved before going into update
double | norm_
| Ratio of size of factorization to number of rows.
double | factorizationRatio_
| Ratio of size of factorization to number of rows.
int | state_
| Status 0) Normal -1) Needs initialization 1) Weights are stored by sequence number.
int | mode_
| If 0 then we are using uninitialized weights, 1 then full, if 2 then uninitialized partial, 3 switchable.
Persistence | persistence_
| Life of weights.
CoinIndexedVector * | weights_
| weight array
CoinIndexedVector * | infeasible_
| square of infeasibility array (just for infeasible rows)
CoinIndexedVector * | savedWeights_
| save weight array (so we can use checkpoint)

## Detailed Description

Dual Row Pivot Steepest Edge Algorithm Class.

See Forrest-Goldfarb paper for algorithm

Definition at line 21 of file AbcDualRowSteepest.hpp.

## Member Enumeration Documentation

enum AbcDualRowSteepest::Persistence

enums for persistence

Enumerator:

  normal |
  keep |

Definition at line 69 of file AbcDualRowSteepest.hpp.

## Constructor & Destructor Documentation

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

Default Constructor 0 is uninitialized, 1 full, 2 is partial uninitialized, 3 starts as 2 but may switch to 1.

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

AbcDualRowSteepest::AbcDualRowSteepest | ( | const AbcDualRowSteepest & |  | ) |

Copy constructor.

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

Destructor.

## Member Function Documentation

virtual int AbcDualRowSteepest::pivotRow | ( |  | ) | `[virtual]`

Returns pivot row, -1 if none.

Implements AbcDualRowPivot.

virtual double AbcDualRowSteepest::updateWeights | ( | CoinIndexedVector & | input,
|  | CoinIndexedVector & | updatedColumn |
| ) |  |  | `[virtual]`

Updates weights and returns pivot alpha.

Also does FT update

Implements AbcDualRowPivot.

virtual double AbcDualRowSteepest::updateWeights1 | ( | CoinIndexedVector & | input,
|  | CoinIndexedVector & | updateColumn |
| ) |  |  | `[virtual]`

Returns pivot row, -1 if none.

Implements AbcDualRowPivot.

virtual void AbcDualRowSteepest::updateWeightsOnly | ( | CoinIndexedVector & | input | ) | `[virtual]`

Returns pivot row, -1 if none.

Implements AbcDualRowPivot.

virtual void AbcDualRowSteepest::updateWeights2 | ( | CoinIndexedVector & | input,
|  | CoinIndexedVector & | updateColumn |
| ) |  |  | `[virtual]`

Actually updates weights.

Implements AbcDualRowPivot.

virtual void AbcDualRowSteepest::updatePrimalSolution | ( | CoinIndexedVector & | input,
|  | double | theta |
| ) |  |  | `[virtual]`

Updates primal solution (and maybe list of candidates) Uses input vector which it deletes.

Implements AbcDualRowPivot.

virtual void AbcDualRowSteepest::updatePrimalSolutionAndWeights | ( | CoinIndexedVector & | weightsVector,
|  | CoinIndexedVector & | updateColumn,
|  | double | theta |
| ) |  |  | `[virtual]`

Returns pivot row, -1 if none.

Reimplemented from AbcDualRowPivot.

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

Saves any weights round factorization as pivot rows may change 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) for strong branching - initialize (uninitialized) , infeasibilities

Reimplemented from AbcDualRowPivot.

virtual void AbcDualRowSteepest::recomputeInfeasibilities | ( |  | ) | `[virtual]`

Recompute infeasibilities.

Reimplemented from AbcDualRowPivot.

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

Gets rid of all arrays.

Reimplemented from AbcDualRowPivot.

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

Returns true if would not find any row.

Reimplemented from AbcDualRowPivot.

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

Assignment operator.

Reimplemented from AbcDualRowPivot.

void AbcDualRowSteepest::fill | ( | const AbcDualRowSteepest & | rhs | ) |

Fill most values.

virtual AbcDualRowPivot* AbcDualRowSteepest::clone | ( | bool | copyData = `true` | ) | const`[virtual]`

Clone.

Implements AbcDualRowPivot.

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

Mode.

Definition at line 104 of file AbcDualRowSteepest.hpp.

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

Set/ get persistence.

Definition at line 108 of file AbcDualRowSteepest.hpp.

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

Mode.

Definition at line 111 of file AbcDualRowSteepest.hpp.

CoinIndexedVector* AbcDualRowSteepest::infeasible | ( |  | ) | const`[inline]`

Infeasible vector.

Definition at line 115 of file AbcDualRowSteepest.hpp.

CoinIndexedVector* AbcDualRowSteepest::weights | ( |  | ) | const`[inline]`

Weights vector.

Definition at line 118 of file AbcDualRowSteepest.hpp.

AbcSimplex* AbcDualRowSteepest::model | ( |  | ) | const`[inline]`

Model.

Definition at line 121 of file AbcDualRowSteepest.hpp.

## Member Data Documentation

double AbcDualRowSteepest::norm_`[private]`

Ratio of size of factorization to number of rows.

Definition at line 130 of file AbcDualRowSteepest.hpp.

double AbcDualRowSteepest::factorizationRatio_`[private]`

Ratio of size of factorization to number of rows.

Definition at line 132 of file AbcDualRowSteepest.hpp.

int AbcDualRowSteepest::state_`[private]`

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

Definition at line 138 of file AbcDualRowSteepest.hpp.

int AbcDualRowSteepest::mode_`[private]`

If 0 then we are using uninitialized weights, 1 then full, if 2 then uninitialized partial, 3 switchable.

Definition at line 141 of file AbcDualRowSteepest.hpp.

Persistence AbcDualRowSteepest::persistence_`[private]`

Life of weights.

Definition at line 143 of file AbcDualRowSteepest.hpp.

CoinIndexedVector* AbcDualRowSteepest::weights_`[private]`

weight array

Definition at line 145 of file AbcDualRowSteepest.hpp.

CoinIndexedVector* AbcDualRowSteepest::infeasible_`[private]`

square of infeasibility array (just for infeasible rows)

Definition at line 147 of file AbcDualRowSteepest.hpp.

CoinIndexedVector* AbcDualRowSteepest::savedWeights_`[private]`

save weight array (so we can use checkpoint)

Definition at line 149 of file AbcDualRowSteepest.hpp.

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

- /home/coin/svn-release/Alps-1.4.5/Clp/src/AbcDualRowSteepest.hpp