net.sf.cpsolver.ifs.dbt
Class DbtValueSelection

java.lang.Object
  net.sf.cpsolver.ifs.dbt.DbtValueSelection

All Implemented Interfaces:

ValueSelection

public class DbtValueSelection
extends Object
implements ValueSelection

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:

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 1.1 (Iterative Forward Search)
Copyright (C) 2006 Tomáš Müller
muller@unitime.org
Lazenska 391, 76314 Zlin, Czech Republic

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 2.1 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, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

Constructor Summary

DbtValueSelection(DataProperties properties)

Method Summary

void	init(Solver solver) Heuristics initialization
Value	selectValue(Solution solution, Variable 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 solver)

Heuristics initialization

Specified by:

init in interface ValueSelection

See Also:

ValueSelection.init(Solver)

selectValue

public Value selectValue(Solution solution,
                         Variable selectedVariable)

Value selection

Specified by:

selectValue in interface ValueSelection

Parameters:

solution - current solution

selectedVariable - selected variable

See Also:

ValueSelection.selectValue(Solution, Variable)