//protected Random _random = new Random(0);
/// <summary>
/// Liefert die nächste zu belegende Variable zurück.
/// </summary>
/// <remarks>Die Auswahl findet dabei
/// über die MRV-Heuristic statt(Minimum Remaining Values).
/// Haben mehrere Variablen die gleiche Anzahl verbleibender Werte, dann
/// wird die GradHeuristic genutzt, d.h. es wird die Variable genommen, die in
/// den meisten Randbedingungen vorkommt.
/// </remarks>
/// <param name="configuration">Die Konfiguration, die noch nicht belegte Variablen enthält.</param>
/// <param name="constraintList">Die Liste mit den Randbedingungen.</param>
/// <returns>
/// Gibt die als nächstes zu belegende Variable zurück.
/// </returns>
public Variable GetHeuristicVariable(ConstraintConfiguration configuration, ConstraintList constraintList)
{
Variable result = null;
int minDomainValues = 0;
List <Variable> mrvVariables = new List <Variable>();
//// Zufall
//SortedList<double, Variable> sortedList = new SortedList<double, Variable>(configuration.Variables.GetLength(0));
//foreach (Variable var in configuration.Variables)
//{
// sortedList.Add(_random.NextDouble(), var);
//}
//// search the variables with the minimum remaining values
//foreach(Variable var in sortedList.Values)
foreach (Variable var in configuration.Variables)
{
if (!var.HasAsignedValue)
{
if (result == null)
{
result = var;
minDomainValues = var.Domain.Count;
mrvVariables.Add(var);
}
else if (minDomainValues > var.Domain.Count)
{
mrvVariables.Clear();
result = var;
minDomainValues = var.Domain.Count;
mrvVariables.Add(var);
}
else if (minDomainValues == var.Domain.Count)
{
mrvVariables.Add(var);
}
}
}
// are there more then one variables we should use the variable with the most constraints
if (mrvVariables.Count != 1)
{
int countConstraints = 0;
int varCountConstraints = 0;
foreach (Variable var in mrvVariables)
{
varCountConstraints = constraintList.GetConstraints(var.Name).Count;
if (varCountConstraints > countConstraints)
{
result = var;
countConstraints = varCountConstraints;
}
}
}
return(result);
}
/// <summary>
/// Für den übergebenen Knoten werden neue Unterknoten generiert.
/// </summary>
/// <param name="node">Anhand des übergebenen Knotens werden neue Unterknoten
/// generiert.</param>
/// <param name="maxCount">Beschränkt die Anzahl der Unterknoten.</param>
/// <returns>
/// Gibt die Menge der generierten Knoten als Array zurück.
/// </returns>
public virtual INode[] GenerateChildren(INode node, int maxCount)
{
ConstraintConfiguration parentConfiguration = (ConstraintConfiguration)node.Data;
Variable nextVar = _heuristicVariable.GetHeuristicVariable(parentConfiguration, _constraintList);
List <INode> generatedNodes = new List <INode>();
if (nextVar == null)
{
throw new Exception("nextVar is null");
}
//// Zufall
//List<KeyValuePair<double, double>> sortedList = new List<KeyValuePair<double, double>>(nextVar.Domain.Count);
//foreach (double value in nextVar.Domain)
//{
// sortedList.Add(new KeyValuePair<double,double>(_random.NextDouble(), value));
//}
//sortedList.Sort();
//foreach (KeyValuePair<double,double> pair in sortedList)
foreach (double value in nextVar.Domain)
{
ConstraintConfiguration configuration = new ConstraintConfiguration(parentConfiguration);
Variable currentVar = configuration.GetVariable(nextVar.Name);
currentVar.Value = value;
List <Constraint> constraints = _constraintList.GetConstraints(nextVar.Name);
bool operationFailed = false;
foreach (Constraint cons in constraints)
{
bool tempChanging = false;
cons.SetCurrentConfiguration(configuration);
// todo: Ist diese Abfrage wirklich notwendig?
//if (cons.IsComplied == false)
//{
// operationFailed = true;
// break;
//}
if (_consistencyOptions.GetCheckConsistencyActive(ConsistencyCheckRegion.EachNodeGenerating, ConsistencyType.Bounds) && ConstraintForms.CheckBoundsConsistency(cons, ref tempChanging) == false)
{
operationFailed = true;
break;
}
else if (_consistencyOptions.GetCheckConsistencyActive(ConsistencyCheckRegion.EachNodeGenerating, ConsistencyType.Node) && configuration.CheckNodeConsistency(cons, false) == false)
{
operationFailed = true;
break;
}
else if (_consistencyOptions.GetCheckConsistencyActive(ConsistencyCheckRegion.EachNodeGenerating, ConsistencyType.Arc) && CheckArcConsistency(configuration) == false)
{
operationFailed = true;
break;
}
}
if (!operationFailed)
{
// Die Domaene kann gelöscht werden
currentVar.Domain = null;
generatedNodes.Add(CreateNode(node, configuration));
//configuration.Show();
}
}
INode[] result;
result = new INode[generatedNodes.Count];
generatedNodes.CopyTo(result);
return(result);
}