/**
* Establishes arc-consistency for (xi, xj).
* @return value true if the domain of xi was reduced.
*/
private bool makeArcConsistent(VAR xi, VAR xj, IConstraint <VAR, VAL> constraint, CSP <VAR, VAL> csp)
{
Domain <VAL> currDomain = csp.getDomain(xi);
ICollection <VAL> newValues = CollectionFactory.CreateQueue <VAL>();
Assignment <VAR, VAL> assignment = new Assignment <VAR, VAL>();
foreach (VAL vi in currDomain)
{
assignment.add(xi, vi);
foreach (VAL vj in csp.getDomain(xj))
{
assignment.add(xj, vj);
if (constraint.isSatisfiedWith(assignment))
{
newValues.Add(vi);
break;
}
}
}
if (newValues.Size() < currDomain.size())
{
csp.setDomain(xi, new Domain <VAL>(newValues));
return(true);
}
return(false);
}
/**
* Replaces the domain of the specified variable by new domain, which
* contains all values of the old domain except the specified value.
*/
public bool removeValueFromDomain(VAR var, VAL value)
{
Domain <VAL> currDomain = getDomain(var);
ICollection <VAL> values = CollectionFactory.CreateQueue <VAL>();
foreach (VAL v in currDomain)
{
if (!v.Equals(value))
{
values.Add(v);
}
}
if (values.Size() < currDomain.size())
{
setDomain(var, new Domain <VAL>(values));
return(true);
}
return(false);
}