public void Update(CFKRNode x, CFKRNode y)
{
var LCPAndZeta = GetLCP(x, y);
y.Label.Clear();
foreach (var l in LCPAndZeta.Item1)
{
y.Label.Add(l);
}
foreach (var l in LCPAndZeta.Item2)
{
y.Label.Add(l);
}
if (y.Rank != Infinity)
{
y.Label.Add(y);
}
// TODO If `(y) was updated then for all arcs (y, w) ∈ E, recursively apply update(y, w).
foreach (var node in y.Outgoing)
{
Update(y, node);
}
}
public Message(CFKRNode v, List<CFKRNode> label)
{
V = v;
Label = label;
}
public ReturnMessage BVisit(CFKRNode w, Message msg)
{
if(w.Index == msg.V.Index)
return ReturnMessage.Cycle;
if (Equals(w, msg.V) && !w.Visited(visitedCurrentRound))
{
foreach (var inNode in w.Incoming)
{
if(BVisit(inNode, msg) == ReturnMessage.Cycle)
return ReturnMessage.Cycle;
}
}
return ReturnMessage.NoCycle;
}
public ReturnMessage FVisit(CFKRNode w, CFKRNode u)
{
if(w.Visited(visitedCurrentRound) || u.Index == w.Index)
return ReturnMessage.Cycle;
if (GreaterThan(u, w) && !w.VisitedForward(visitedCurrentRound))
{
foreach (var outNode in w.Outgoing)
{
if(FVisit(outNode, u) == ReturnMessage.Cycle)
return ReturnMessage.Cycle;
}
}
return ReturnMessage.NoCycle;
}
public bool CycleDetect(CFKRNode u, CFKRNode v)
{
var backMessage = BVisit(u, new Message(v, u.Label));
if (backMessage == ReturnMessage.Cycle)
return true;
var forwardMessage = FVisit(v, u);
if (forwardMessage == ReturnMessage.Cycle)
return true;
return false;
}
// Item1 = LCP
// Item2 = Zeta
public Tuple<List<CFKRNode>, List<CFKRNode>> GetLCP(CFKRNode x, CFKRNode y)
{
int i = 0;
while (x.Label.Count > i && y.Label.Count > i && x.Label[i].Index == y.Label[i].Index)
{
i++;
}
var lcp = new List<CFKRNode>(i+1);
for (int b = 0; b < i; b++)
{
lcp.Add(x.Label[b]);
}
var zeta = new List<CFKRNode>();
for (int b = i; b < x.Label.Count; b++)
{
zeta.Add(x.Label[b]);
}
var zetaPrime = new List<CFKRNode>();
if(zeta.Count > 0)
zetaPrime.Add(zeta[0]);
for (int b = 1; b < zeta.Count; b++)
{
if(zeta[b].Rank < y.Rank)
zetaPrime.Add(zeta[b]);
else
break;
}
return new Tuple<List<CFKRNode>, List<CFKRNode>>(lcp, zetaPrime);
}
