// This is experimental (for now at least), trying to see if we can swap edges and change assortativity while
// maintaining the degree vector, really need to reorganize this part. Would move it to a new class that inherits
// from Graph, but I want to use it in ER and BA..
public bool SwapRandomEdgesToIncreaseAssortativity()
{
Randomizer rand = new Randomizer();
var edges = EdgesAsNodes.ToList();
var e1 = edges[rand.Next(edges.Count)];
var e2 = edges[rand.Next(edges.Count)];
if (e1.Item1 == e2.Item1 || e1.Item1 == e2.Item2 || e1.Item2 == e2.Item1 || e1.Item2 == e2.Item2)
{
return(false);
}
var currVal = ((double)Math.Max(e1.Item1.Degree, e1.Item2.Degree) /
Math.Min(e1.Item1.Degree, e1.Item2.Degree) +
(double)Math.Max(e2.Item1.Degree, e2.Item2.Degree) /
Math.Min(e2.Item1.Degree, e2.Item2.Degree)) / 2.0;
var e1Ae2A = ((double)Math.Max(e1.Item1.Degree, e2.Item1.Degree) /
Math.Min(e1.Item1.Degree, e2.Item1.Degree) +
(double)Math.Max(e1.Item2.Degree, e2.Item2.Degree) /
Math.Min(e1.Item2.Degree, e2.Item2.Degree)) / 2.0;
var e1Ae2B = ((double)Math.Max(e1.Item1.Degree, e2.Item2.Degree) /
Math.Min(e1.Item1.Degree, e2.Item2.Degree) +
(double)Math.Max(e1.Item2.Degree, e2.Item1.Degree) /
Math.Min(e1.Item2.Degree, e2.Item1.Degree)) / 2.0;
String oldDegSeq = String.Join(",", DegreeVector);
if (e1Ae2A < currVal && e1Ae2A < e1Ae2B &&
!e1.Item1.Neighbors.Contains(e2.Item1) && !e1.Item2.Neighbors.Contains(e2.Item2))
{
RemoveEdge(e1.Item1, e1.Item2);
RemoveEdge(e2.Item1, e2.Item2);
AddEdge(e1.Item1, e2.Item1);
AddEdge(e1.Item2, e2.Item2);
if (oldDegSeq != String.Join(",", DegreeVector))
{
throw new Exception("Holy cow");
}
return(true);
}
else if (e1Ae2B < currVal && e1Ae2B < e1Ae2A &&
!e1.Item1.Neighbors.Contains(e2.Item2) && !e1.Item2.Neighbors.Contains(e2.Item1))
{
RemoveEdge(e1.Item1, e1.Item2);
RemoveEdge(e2.Item1, e2.Item2);
AddEdge(e1.Item1, e2.Item2);
AddEdge(e1.Item2, e2.Item1);
if (oldDegSeq != String.Join(",", DegreeVector))
{
throw new Exception("Holy cow");
}
return(true);
}
return(false);
}