// Returns a list of partitions represented by SetPartition<T>
// An old reference to the set is hold by SetPartition<T>::Difference
// An intersection is given by SetPartition<T>::Intersection which can
// be invalidaded with further actions on the instance of ProductRefinement
public List <SetPartition <T> > Refine(ICollection <T> elements)
{
var changedNodes = new List <LinkedListNode <SetPartition <T> > > ();
foreach (var el in elements)
{
pointers [el].ToSet.Value.CloseIntersection();
}
foreach (var el in elements)
{
var p = pointers [el];
if (!p.ToSet.Value.HasIntersection())
{
p.ToSet.Value.InitIntersection();
changedNodes.Add(p.ToSet);
}
var newIt = p.ToSet.Value.Intersect(p.ToIterator);
p.ToIterator = newIt;
}
foreach (var partNode in changedNodes)
{
if (!partNode.Value.Difference.Any())
{
foreach (T el in partNode.Value.Intersection)
{
var backIt = partNode.Value.Difference.AddLast(el);
pointers[el].ToIterator = backIt;
}
partNode.Value.Intersection.Clear();
continue;
}
var intersectionPart = new SetPartition <T> (partNode.Value.Intersection);
var node = partition.AddLast(intersectionPart);
foreach (T el in partNode.Value.Intersection)
{
pointers [el].ToSet = node;
}
}
var changes = new List <SetPartition <T> > ();
foreach (var node in changedNodes)
{
if (node.Value.Intersection.Any())
{
changes.Add(node.Value);
}
}
return(changes);
}
// list of sets depicting initial partition
public PartitionRefinement(IList <LinkedList <T> > sets)
{
foreach (var elements in sets)
{
var newSet = new SetPartition <T> (elements);
var node = partition.AddLast(newSet);
var iterator = elements.First;
while (iterator != null)
{
pointers [iterator.Value] = new Pointer(node, iterator);
iterator = iterator.Next;
}
}
}