org.cpsolver.ifs.dbt

Class DbtValueSelection<V extends Variable<V,T>,T extends Value<V,T>>

java.lang.Object

org.cpsolver.ifs.dbt.DbtValueSelection<V,T>

Type Parameters:

V - Variable

T - Value

All Implemented Interfaces:

ValueSelection<V,T>

public class DbtValueSelection<V extends Variable<V,T>,T extends Value<V,T>>
extends Object
implements ValueSelection<V,T>

Selection of a value for dynamic backtracking.

• Returns null if all values of the selected variable are nogood.
• Selected the best good value (according to the parameters) of the selected variable.

It is based on a weighted sum of several criteria.

This IFS solver value selection heuristics is to be used only in case of dynamic backtracking and it has the following parameters:

Related Solver Parameters

Parameter	Type	Comment
General.MPP	Boolean	Minimal Perturbation Problem
Value.MPPLimit	Integer	Limit on the number of perturbations (only in case of MPP, i.e., when General.MPP=true). MPP limit is decreased when a complete solution is found. If set to -1, it is no used
Value.InitialSelectionProb	Double	Probability of selection of initial value (only in case of MPP)
Value.WeightDeltaInitialAssignments	Double	Weight of difference in the number of assignments of initial values in case of selection of the value(only in case of MPP)
Value.RandomWalkProb	Double	Probability of random selection of a good value
Value.WeightNrAssignments	Double	Weight of the number of previous assignments of the value
Value.WeightValue	Double	Weight of the value itself (e.g., for minCSP)

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/.

Author:

Tomáš Müller

Constructor Summary

Constructors

Constructor and Description
DbtValueSelection(DataProperties properties)

Method Summary

Modifier and Type	Method and Description
void	init(Solver<V,T> solver) Heuristics 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

Constructor Detail

DbtValueSelection

public DbtValueSelection(DataProperties properties)

Method Detail

init

public void init(Solver<V,T> solver)

Heuristics initialization

Specified by:

init in interface ValueSelection<V extends Variable<V,T>,T extends Value<V,T>>

Parameters:

solver - current solver

See Also:

ValueSelection.init(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)

See Also:

ValueSelection.selectValue(Solution, Variable)