public static PTD ExtendToPMC_Rule2(PTD Tau_wiggle, BitSet vNeighbors, ImmutableGraph graph)
{
BitSet bag = new BitSet(vNeighbors);
List <PTD> children = new List <PTD>(Tau_wiggle.children);
BitSet vertices = new BitSet(Tau_wiggle.vertices);
vertices.UnionWith(vNeighbors);
BitSet outlet = graph.Outlet(bag, vertices);
BitSet inlet = new BitSet(vertices);
inlet.ExceptWith(outlet);
return(new PTD(bag, vertices, outlet, inlet, children));
}
public static PTD ExtendToPMC_Rule3(PTD Tau_wiggle, BitSet newRoot, ImmutableGraph graph)
{
Debug.Assert(newRoot.IsSupersetOf(Tau_wiggle.Bag));
BitSet bag = newRoot;
BitSet vertices = new BitSet(Tau_wiggle.vertices);
vertices.UnionWith(newRoot);
List <PTD> children = new List <PTD>(Tau_wiggle.children);
BitSet outlet = graph.Outlet(bag, vertices);
BitSet inlet = new BitSet(vertices);
inlet.ExceptWith(outlet);
return(new PTD(bag, vertices, outlet, inlet, children));
}
/// <summary>
/// a method extracted from the method above due to performance reasons. Read it as if the body of the method above would just continue here.
/// </summary>
/// <param name="Tau_prime">the ptdur</param>
/// <param name="Tau">the ptd</param>
/// <param name="graph">the underlying graph</param>
/// <param name="result">the resulting ptd, or null if the return value is false</param>
/// <param name="bag">the bag of the ptd to be</param>
/// <returns>true, iff the resulting ptd is possibly usable</returns>
private static bool AddPTDToPTDUR_CheckPossiblyUsable_CheckCliquish_Helper(PTD Tau_prime, PTD Tau, ImmutableGraph graph, out PTD result, BitSet bag, uint futureBagSize, int k, Graph mutableGraph)
{
List <PTD> children = new List <PTD>(Tau_prime.children);
children.Add(Tau);
// exit early if not possibly usable
if (!IsPossiblyUsable(children, graph))
{
result = null;
return(false);
}
// if no vertices can be added to the bag due to size and the bag is not a pmc, we can reject this ptd immediately because it is not useful
if (futureBagSize == k + 1 && !graph.IsPotMaxClique(bag))
{
result = null;
return(false);
}
if (!graph.IsCliquish(bag))
{
result = null;
return(false);
}
// if only one vertex can be added, determine all the candidates that would make this bag a pmc when added. If there are none, return.
if (testIfAddingOneVertexToBagFormsPMC && futureBagSize == k)
{
// if bag is pmc already, we need this ptdur. (In that case no candidate exists which could be added.)
if (!graph.IsPotMaxClique(bag))
{
bool useless = true;
foreach ((BitSet component, BitSet neighbor) in graph.ComponentsAndNeighbors(bag))
{
// candidates are only found in full components
if (neighbor.Equals(bag) && !component.Intersects(Tau_prime.vertices) && !component.Intersects(Tau.vertices))
{
if (neighborsFirst)
{
onlyNeighborStopwatch.Start();
// test if a vertex in the bag has exactly one neighbor in this component, and the bag plus that vertex is still cliquish
foreach (int v in bag.Elements())
{
BitSet neighbors = new BitSet(graph.openNeighborhood[v]);
neighbors.IntersectWith(component);
if (neighbors.Count() == 1)
{
int candidate = neighbors.First();
bag[candidate] = true;
if (graph.IsCliquish(bag)) // in this case it is guaranteed that the bag is also a pmc
{
Debug.Assert(graph.IsPotMaxClique(bag));
bag[candidate] = false;
useless = false;
break;
}
bag[candidate] = false;
}
}
onlyNeighborStopwatch.Stop();
if (!useless)
{
break;
}
}
articulationPointCandidatesStopwatch.Start();
// find articulation points within this component
foreach (int articulationPoint in SafeSeparator.ArticulationPoints(mutableGraph, component))
{
bag[articulationPoint] = true;
if (graph.IsPotMaxClique(bag))
{
bag[articulationPoint] = false;
useless = false;
break;
}
bag[articulationPoint] = false;
}
articulationPointCandidatesStopwatch.Stop();
if (!useless)
{
break;
}
if (!neighborsFirst)
{
onlyNeighborStopwatch.Start();
// test if a vertex in the bag has exactly one neighbor in this component, and the bag plus that vertex is still cliquish
foreach (int v in bag.Elements())
{
BitSet neighbors = new BitSet(graph.openNeighborhood[v]);
neighbors.IntersectWith(component);
if (neighbors.Count() == 1)
{
int candidate = neighbors.First();
bag[candidate] = true;
if (graph.IsCliquish(bag)) // in this case it is guaranteed that the bag is also a pmc
{
Debug.Assert(graph.IsPotMaxClique(bag));
bag[candidate] = false;
useless = false;
break;
}
bag[candidate] = false;
}
}
onlyNeighborStopwatch.Stop();
if (!useless)
{
break;
}
}
// TODO: possibly exclude candidates that are in this ptdur's inlet? Is that correct?
}
}
if (useless)
{
result = null;
return(false);
}
}
}
// usability is established, so we build the ptd
BitSet vertices = new BitSet(Tau_prime.vertices);
vertices.UnionWith(Tau.vertices);
BitSet outlet = graph.Outlet(bag, vertices);
BitSet inlet = new BitSet(vertices);
inlet.ExceptWith(outlet);
result = new PTD(new BitSet(bag), vertices, outlet, inlet, children);
return(true);
}