org.cpsolver.ifs.heuristics

## Class GeneralValueSelection<V extends Variable<V,T>,T extends Value<V,T>>

• Type Parameters:
`V` - Variable
`T` - Value
All Implemented Interfaces:
ValueSelection<V,T>

```public class GeneralValueSelection<V extends Variable<V,T>,T extends Value<V,T>>
extends Object
implements ValueSelection<V,T>```
General implementation of value selection criterion.

Value selection criterion is based on weighted sum of various criteria. It also allows random walk technique and tabu search.
Parameters:
Parameter Type Comment
General.MPP `Boolean` if true, MPP is being solved
Value.MPPLimit `Integer` MPP: limitation of the number of allowed perturbations. If a solution within this limit is gound, it is decreased.
Value.InitialSelectionProb `Double` MPP: probability of selection of the initial value
Value.RandomWalkProb `Double` Random Walk: probability of selection of a value randomly among all the values
Value.Tabu `Integer` Tabu Search: length of the tabu-list
Value.GoodSelectionProb `Double` In case of `MacPropagation`, with this probability (1.0 means always), the selection is made only among good values (not removed from the domain).

Following weights are used in the weighted sum (computed for all values). The value with the lowest weighted sum is selected. If there are more than one of such values, one of them is selected randomly.
Parameter Type Comment
Value.WeightDeltaInitialAssignments `Double` MPP: Difference in the number of assigned initial values if the value is assigned to the variable (weighted by this Value.WeightDeltaInitialAssignments): -1 if the value is initial, 0 otherwise, increased by the number of initial values assigned to variables with hard conflicts with the value
Value.WeightWeightedConflicts `Double` When `ConflictStatistics` is used: weighted number of conflicting variables
Value.WeightPotentialConflicts `Double` When `ConflictStatistics` is used: weighted number of potentially conflicting variables
Value.WeightConflicts `Double` Number of conflicting variables `Model.conflictValues(Assignment, Value)`.
Value.WeightValue `Double` Value `Value.toDouble(Assignment)`
Version:
IFS 1.3 (Iterative Forward Search)
Copyright (C) 2006 - 2014 Tomáš Müller
muller@unitime.org
http://muller.unitime.org

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not see http://www.gnu.org/licenses.
`VariableSelection`, `Solver`
• ### Field Summary

Fields
Modifier and Type Field and Description
`protected ArrayList<T>` `iTabu`
`protected int` `iTabuPos`
`protected int` `iTabuSize`
• ### Constructor Summary

Constructors
Constructor and Description
`GeneralValueSelection()`
`GeneralValueSelection(DataProperties properties)`
Constructor
• ### Method Summary

All Methods
Modifier and Type Method and Description
`void` `init(Solver<V,T> solver)`
Initialization
`T` ```selectValue(Solution<V,T> solution, V selectedVariable)```
Value selection
• ### Methods inherited from class java.lang.Object

`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`
• ### Field Detail

• #### iTabuSize

`protected int iTabuSize`
• #### iTabu

`protected ArrayList<T extends Value<V,T>> iTabu`
• #### iTabuPos

`protected int iTabuPos`
• ### Constructor Detail

• #### GeneralValueSelection

`public GeneralValueSelection()`
• #### GeneralValueSelection

`public GeneralValueSelection(DataProperties properties)`
Constructor
Parameters:
`properties` - input configuration
• ### Method Detail

• #### init

`public void init(Solver<V,T> solver)`
Initialization
Specified by:
`init` in interface `ValueSelection<V extends Variable<V,T>,T extends Value<V,T>>`
Parameters:
`solver` - current solver
• #### selectValue

```public T selectValue(Solution<V,T> solution,
V selectedVariable)```
Value selection
Specified by:
`selectValue` in interface `ValueSelection<V extends Variable<V,T>,T extends Value<V,T>>`
Parameters:
`solution` - current solution
`selectedVariable` - selected variable
Returns:
selected value (of the given variable)