# Idiot Class Reference

This class implements a very silly algorithm. More...

`#include <Idiot.hpp>`

Collaboration diagram for Idiot:
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List of all members.

## Public Member Functions
void | solve2 (CoinMessageHandler *handler, const CoinMessages *messages)
| Stuff for internal use.
Constructors and destructor
Just a pointer to model is kept
| Idiot ()
| Default constructor.
| Idiot (OsiSolverInterface &model)
| Constructor with model.
| Idiot (const Idiot &)
| Copy constructor.
Idiot & | operator= (const Idiot &rhs)
| Assignment operator. This copies the data.
| ~Idiot ()
| Destructor.
Algorithmic calls
void | solve ()
| Get an approximate solution with the idiot code.
void | crash (int numberPass, CoinMessageHandler *handler, const CoinMessages *messages, bool doCrossover=true)
| Lightweight "crash".
void | crossOver (int mode)
| Use simplex to get an optimal solution mode is how many steps the simplex crossover should take to arrive to an extreme point: 0 - chosen,all ever used, all 1 - chosen, all 2 - all 3 - do not do anything - maybe basis + 16 do presolves.
Gets and sets of most useful data
double | getStartingWeight () const
| Starting weight - small emphasizes feasibility, default 1.0e-4.
void | setStartingWeight (double value)
double | getWeightFactor () const
| Weight factor - weight multiplied by this when changes, default 0.333.
void | setWeightFactor (double value)
double | getFeasibilityTolerance () const
| Feasibility tolerance - problem essentially feasible if individual infeasibilities less than this.
void | setFeasibilityTolerance (double value)
double | getReasonablyFeasible () const
| Reasonably feasible.
void | setReasonablyFeasible (double value)
double | getExitInfeasibility () const
| Exit infeasibility - exit if sum of infeasibilities less than this.
void | setExitInfeasibility (double value)
int | getMajorIterations () const
| Major iterations.
void | setMajorIterations (int value)
int | getMinorIterations () const
| Minor iterations.
void | setMinorIterations (int value)
int | getMinorIterations0 () const
void | setMinorIterations0 (int value)
int | getReduceIterations () const
| Reduce weight after this many major iterations.
void | setReduceIterations (int value)
int | getLogLevel () const
| Amount of information - default of 1 should be okay.
void | setLogLevel (int value)
int | getLightweight () const
| How lightweight - 0 not, 1 yes, 2 very lightweight.
void | setLightweight (int value)
int | getStrategy () const
| strategy
void | setStrategy (int value)
double | getDropEnoughFeasibility () const
| Fine tuning - okay if feasibility drop this factor.
void | setDropEnoughFeasibility (double value)
double | getDropEnoughWeighted () const
| Fine tuning - okay if weighted obj drop this factor.
void | setDropEnoughWeighted (double value)
## Private Member Functions
IdiotResult | IdiSolve (int nrows, int ncols, double *rowsol, double *colsol, double *pi, double *djs, const double *origcost, double *rowlower, double *rowupper, const double *lower, const double *upper, const double *element, const int *row, const CoinBigIndex *colcc, const int *length, double *lambda, int maxIts, double mu, double drop, double maxmin, double offset, int strategy, double djTol, double djExit, double djFlag, CoinThreadRandom *randomNumberGenerator)
int | dropping (IdiotResult result, double tolerance, double small, int *nbad)
IdiotResult | objval (int nrows, int ncols, double *rowsol, double *colsol, double *pi, double *djs, const double *cost, const double *rowlower, const double *rowupper, const double *lower, const double *upper, const double *elemnt, const int *row, const CoinBigIndex *columnStart, const int *length, int extraBlock, int *rowExtra, double *solExtra, double *elemExtra, double *upperExtra, double *costExtra, double weight)
int | cleanIteration (int iteration, int ordinaryStart, int ordinaryEnd, double *colsol, const double *lower, const double *upper, const double *rowLower, const double *rowUpper, const double *cost, const double *element, double fixTolerance, double &objChange, double &infChange)
## Private Attributes
OsiSolverInterface * | model_
| Underlying model.
double | djTolerance_
double | mu_
double | drop_
double | muFactor_
double | stopMu_
double | smallInfeas_
double | reasonableInfeas_
double | exitDrop_
double | muAtExit_
double | exitFeasibility_
double | dropEnoughFeasibility_
double | dropEnoughWeighted_
int * | whenUsed_
int | maxBigIts_
int | maxIts_
int | majorIterations_
int | logLevel_
int | logFreq_
int | checkFrequency_
int | lambdaIterations_
int | maxIts2_
int | strategy_
int | lightWeight_

## Detailed Description

This class implements a very silly algorithm.

It has no merit apart from the fact that it gets an approximate solution to some classes of problems. Better if vaguely homogeneous. It works on problems where volume algorithm works and often gets a better primal solution but it has no dual solution.

It can also be used as a "crash" to get a problem started. This is probably its most useful function.

It is based on the idea that algorithms with terrible convergence properties may be okay at first. Throw in some random dubious tricks and the resulting code may be worth keeping as long as you don't look at it.

Definition at line 48 of file Idiot.hpp.

## Constructor & Destructor Documentation

Idiot::Idiot | ( |  | ) |

Default constructor.

Idiot::Idiot | ( | OsiSolverInterface & | model | ) |

Constructor with model.

Idiot::Idiot | ( | const Idiot & |  | ) |

Copy constructor.

Idiot::~Idiot | ( |  | ) |

Destructor.

## Member Function Documentation

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

Assignment operator. This copies the data.

void Idiot::solve | ( |  | ) |

Get an approximate solution with the idiot code.

void Idiot::crash | ( | int | numberPass,
|  | CoinMessageHandler * | handler,
|  | const CoinMessages * | messages,
|  | bool | doCrossover = `true` |
| ) |  |  |

Lightweight "crash".

void Idiot::crossOver | ( | int | mode | ) |

Use simplex to get an optimal solution mode is how many steps the simplex crossover should take to arrive to an extreme point: 0 - chosen,all ever used, all 1 - chosen, all 2 - all 3 - do not do anything - maybe basis + 16 do presolves.

double Idiot::getStartingWeight | ( |  | ) | const`[inline]`

Starting weight - small emphasizes feasibility, default 1.0e-4.

Definition at line 96 of file Idiot.hpp.

void Idiot::setStartingWeight | ( | double | value | ) | `[inline]`

Definition at line 99 of file Idiot.hpp.

double Idiot::getWeightFactor | ( |  | ) | const`[inline]`

Weight factor - weight multiplied by this when changes, default 0.333.

Definition at line 104 of file Idiot.hpp.

void Idiot::setWeightFactor | ( | double | value | ) | `[inline]`

Definition at line 107 of file Idiot.hpp.

double Idiot::getFeasibilityTolerance | ( |  | ) | const`[inline]`

Feasibility tolerance - problem essentially feasible if individual infeasibilities less than this.

default 0.1

Definition at line 113 of file Idiot.hpp.

void Idiot::setFeasibilityTolerance | ( | double | value | ) | `[inline]`

Definition at line 116 of file Idiot.hpp.

double Idiot::getReasonablyFeasible | ( |  | ) | const`[inline]`

Reasonably feasible.

Dubious method concentrates more on objective when sum of infeasibilities less than this. Very dubious default value of (Number of rows)/20

Definition at line 122 of file Idiot.hpp.

void Idiot::setReasonablyFeasible | ( | double | value | ) | `[inline]`

Definition at line 125 of file Idiot.hpp.

double Idiot::getExitInfeasibility | ( |  | ) | const`[inline]`

Exit infeasibility - exit if sum of infeasibilities less than this.

Default -1.0 (i.e. switched off)

Definition at line 130 of file Idiot.hpp.

void Idiot::setExitInfeasibility | ( | double | value | ) | `[inline]`

Definition at line 133 of file Idiot.hpp.

int Idiot::getMajorIterations | ( |  | ) | const`[inline]`

Major iterations.

stop after this number. Default 30. Use 2-5 for "crash" 50-100 for serious crunching

Definition at line 138 of file Idiot.hpp.

void Idiot::setMajorIterations | ( | int | value | ) | `[inline]`

Definition at line 141 of file Idiot.hpp.

int Idiot::getMinorIterations | ( |  | ) | const`[inline]`

Minor iterations.

Do this number of tiny steps before deciding whether to change weights etc. Default - dubious sqrt(Number of Rows). Good numbers 105 to 405 say (5 is dubious method of making sure idiot is not trying to be clever which it may do every 10 minor iterations)

Definition at line 150 of file Idiot.hpp.

void Idiot::setMinorIterations | ( | int | value | ) | `[inline]`

Definition at line 153 of file Idiot.hpp.

int Idiot::getMinorIterations0 | ( |  | ) | const`[inline]`

Definition at line 157 of file Idiot.hpp.

void Idiot::setMinorIterations0 | ( | int | value | ) | `[inline]`

Definition at line 160 of file Idiot.hpp.

int Idiot::getReduceIterations | ( |  | ) | const`[inline]`

Reduce weight after this many major iterations.

It may get reduced before this but this is a maximum. Default 3. 3-10 plausible.

Definition at line 166 of file Idiot.hpp.

void Idiot::setReduceIterations | ( | int | value | ) | `[inline]`

Definition at line 169 of file Idiot.hpp.

int Idiot::getLogLevel | ( |  | ) | const`[inline]`

Amount of information - default of 1 should be okay.

Definition at line 173 of file Idiot.hpp.

void Idiot::setLogLevel | ( | int | value | ) | `[inline]`

Definition at line 176 of file Idiot.hpp.

int Idiot::getLightweight | ( |  | ) | const`[inline]`

How lightweight - 0 not, 1 yes, 2 very lightweight.

Definition at line 180 of file Idiot.hpp.

void Idiot::setLightweight | ( | int | value | ) | `[inline]`

Definition at line 183 of file Idiot.hpp.

int Idiot::getStrategy | ( |  | ) | const`[inline]`

strategy

Definition at line 187 of file Idiot.hpp.

void Idiot::setStrategy | ( | int | value | ) | `[inline]`

Definition at line 190 of file Idiot.hpp.

double Idiot::getDropEnoughFeasibility | ( |  | ) | const`[inline]`

Fine tuning - okay if feasibility drop this factor.

Definition at line 194 of file Idiot.hpp.

void Idiot::setDropEnoughFeasibility | ( | double | value | ) | `[inline]`

Definition at line 197 of file Idiot.hpp.

double Idiot::getDropEnoughWeighted | ( |  | ) | const`[inline]`

Fine tuning - okay if weighted obj drop this factor.

Definition at line 201 of file Idiot.hpp.

void Idiot::setDropEnoughWeighted | ( | double | value | ) | `[inline]`

Definition at line 204 of file Idiot.hpp.

void Idiot::solve2 | ( | CoinMessageHandler * | handler,
|  | const CoinMessages * | messages |
| ) |  |  |

Stuff for internal use.

Does actual work

IdiotResult Idiot::IdiSolve | ( | int | nrows,
|  | int | ncols,
|  | double * | rowsol,
|  | double * | colsol,
|  | double * | pi,
|  | double * | djs,
|  | const double * | origcost,
|  | double * | rowlower,
|  | double * | rowupper,
|  | const double * | lower,
|  | const double * | upper,
|  | const double * | element,
|  | const int * | row,
|  | const CoinBigIndex * | colcc,
|  | const int * | length,
|  | double * | lambda,
|  | int | maxIts,
|  | double | mu,
|  | double | drop,
|  | double | maxmin,
|  | double | offset,
|  | int | strategy,
|  | double | djTol,
|  | double | djExit,
|  | double | djFlag,
|  | CoinThreadRandom * | randomNumberGenerator |
| ) |  |  | `[private]`

int Idiot::dropping | ( | IdiotResult | result,
|  | double | tolerance,
|  | double | small,
|  | int * | nbad |
| ) |  |  | `[private]`

IdiotResult Idiot::objval | ( | int | nrows,
|  | int | ncols,
|  | double * | rowsol,
|  | double * | colsol,
|  | double * | pi,
|  | double * | djs,
|  | const double * | cost,
|  | const double * | rowlower,
|  | const double * | rowupper,
|  | const double * | lower,
|  | const double * | upper,
|  | const double * | elemnt,
|  | const int * | row,
|  | const CoinBigIndex * | columnStart,
|  | const int * | length,
|  | int | extraBlock,
|  | int * | rowExtra,
|  | double * | solExtra,
|  | double * | elemExtra,
|  | double * | upperExtra,
|  | double * | costExtra,
|  | double | weight |
| ) |  |  | `[private]`

int Idiot::cleanIteration | ( | int | iteration,
|  | int | ordinaryStart,
|  | int | ordinaryEnd,
|  | double * | colsol,
|  | const double * | lower,
|  | const double * | upper,
|  | const double * | rowLower,
|  | const double * | rowUpper,
|  | const double * | cost,
|  | const double * | element,
|  | double | fixTolerance,
|  | double & | objChange,
|  | double & | infChange |
| ) |  |  | `[private]`

## Member Data Documentation

OsiSolverInterface* Idiot::model_`[private]`

Underlying model.

Definition at line 251 of file Idiot.hpp.

double Idiot::djTolerance_`[private]`

Definition at line 253 of file Idiot.hpp.

double Idiot::mu_`[private]`

Definition at line 254 of file Idiot.hpp.

double Idiot::drop_`[private]`

Definition at line 255 of file Idiot.hpp.

double Idiot::muFactor_`[private]`

Definition at line 256 of file Idiot.hpp.

double Idiot::stopMu_`[private]`

Definition at line 257 of file Idiot.hpp.

double Idiot::smallInfeas_`[private]`

Definition at line 258 of file Idiot.hpp.

double Idiot::reasonableInfeas_`[private]`

Definition at line 259 of file Idiot.hpp.

double Idiot::exitDrop_`[private]`

Definition at line 260 of file Idiot.hpp.

double Idiot::muAtExit_`[private]`

Definition at line 261 of file Idiot.hpp.

double Idiot::exitFeasibility_`[private]`

Definition at line 262 of file Idiot.hpp.

double Idiot::dropEnoughFeasibility_`[private]`

Definition at line 263 of file Idiot.hpp.

double Idiot::dropEnoughWeighted_`[private]`

Definition at line 264 of file Idiot.hpp.

int* Idiot::whenUsed_`[private]`

Definition at line 265 of file Idiot.hpp.

int Idiot::maxBigIts_`[private]`

Definition at line 266 of file Idiot.hpp.

int Idiot::maxIts_`[private]`

Definition at line 267 of file Idiot.hpp.

int Idiot::majorIterations_`[private]`

Definition at line 268 of file Idiot.hpp.

int Idiot::logLevel_`[private]`

Definition at line 269 of file Idiot.hpp.

int Idiot::logFreq_`[private]`

Definition at line 270 of file Idiot.hpp.

int Idiot::checkFrequency_`[private]`

Definition at line 271 of file Idiot.hpp.

int Idiot::lambdaIterations_`[private]`

Definition at line 272 of file Idiot.hpp.

int Idiot::maxIts2_`[private]`

Definition at line 273 of file Idiot.hpp.

int Idiot::strategy_`[private]`

Definition at line 274 of file Idiot.hpp.

int Idiot::lightWeight_`[private]`

Definition at line 286 of file Idiot.hpp.

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

- /home/coin/svn-release/Clp-1.15.11/Clp/src/Idiot.hpp

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