private void checkLinksTowardsMin(PosetNode <T> node, HashSet <PosetNode <T> > links)
{
if (node != null)
{
if (FindEqual(node.Elements[0]) == null)
{
throw new InternalErrorException("Not findable!");
}
if (findEqualDownwards(node.Elements[0]) == null)
{
throw new InternalErrorException("Not findable!");
}
foreach (var l in links)
{
if (!l._largers.Contains(node))
{
throw new InternalErrorException("Links inconsistent");
}
}
}
foreach (var pair in links.UniquePairs())
{
if (pair.Item1 == pair.Item2)
{
throw new InternalErrorException("Duplicate link");
}
}
foreach (var l in links)
{
checkLinksTowardsMin(l, l._smallers);
}
}
/// <summary>
/// Adds an element to the poset. If available, the element will be added to an existing
/// equivalence class (node), otherwise a new one will be created, and the DAGs will be
/// updated as appropriate.
/// </summary>
public void Add(T element)
{
PosetNode <T> node;
node = FindEqual(element);
if (node != null)
{
node.AddElement(element);
return;
}
node = new PosetNode <T>(element);
add(true, node, _minimals, null);
add(false, node, _maximals, null);
}
private void add(bool upwards, PosetNode <T> toadd, HashSet <PosetNode <T> > links, PosetNode <T> linkfrom)
{
bool any = false;
List <PosetNode <T> > links_add = null;
List <PosetNode <T> > links_del = null;
foreach (var linkto in links)
{
var partcmp = toadd.PartialCompareTo(linkto);
if (partcmp == PartialComparisonResult.Equal)
{
any = true;
if (!object.ReferenceEquals(linkto, toadd))
{
throw new InternalErrorException("Equal poset nodes are not the same instance");
}
}
else if ((upwards && partcmp == PartialComparisonResult.Greater) || (!upwards && partcmp == PartialComparisonResult.Less))
{
any = true;
add(upwards, toadd, upwards ? linkto._largers : linkto._smallers, linkto);
}
else if ((upwards && partcmp == PartialComparisonResult.Less) || (!upwards && partcmp == PartialComparisonResult.Greater))
{
any = true;
if (links_add == null)
{
links_add = new List <PosetNode <T> >();
}
links_add.Add(toadd);
if (links_del == null)
{
links_del = new List <PosetNode <T> >();
}
links_del.Add(linkto);
if (linkfrom != null)
{
(upwards ? toadd._smallers : toadd._largers).Add(linkfrom);
(upwards ? linkto._smallers : linkto._largers).Remove(linkfrom);
}
(upwards ? toadd._largers : toadd._smallers).Add(linkto);
(upwards ? linkto._smallers : linkto._largers).Add(toadd);
}
}
if (links_add != null)
{
foreach (var link in links_add)
{
links.Add(link);
}
}
if (links_del != null)
{
foreach (var link in links_del)
{
links.Remove(link);
}
}
if (!any)
{
links.Add(toadd);
if (linkfrom != null)
{
(upwards ? toadd._smallers : toadd._largers).Add(linkfrom);
}
}
}
/// <summary>
/// Compares this node to the other node, using the partial comparison implemented
/// by the elements stored in the two nodes.
/// </summary>
public PartialComparisonResult PartialCompareTo(PosetNode <T> other)
{
return(_elements[0].PartialCompareTo(other._elements[0]));
}