/// <summary>
/// Returns clustering coefficient of the given node.
/// </summary>
/// <param name="mnet">Multilayer network model.</param>
/// <param name="node">Node to calculate clustering coefficient on.</param>
/// <returns>Clustering coefficient of the given node.</returns>
public double ClusteringCoefficient(MultilayerNetwork mnet, Node node)
{
// Edges between neighbors.
// How well connected are they.
double edgesCount = 0;
// Get all neighbors of the node.
var neighbors = mnet.Neighbors(node, EdgeMode.InOut);
// Degree of the node.
var neighborsCount = neighbors.Count;
if (neighborsCount <= 1)
{
return(0);
}
// Go through all neighbors of our node.
// And check how well connected they are between each other.
foreach (var n1 in neighbors)
{
foreach (var n2 in neighbors)
{
if (n1 == n2)
{
continue;
}
if (mnet.GetEdge(n1, n2) != null)
{
edgesCount++;
}
}
}
return((edgesCount) / (neighborsCount * (neighborsCount - 1)));
}
// Possible to sort nodes.
// and in each loop go only through nodes with higher degree and higher id.
private double ClusteringCoefficient_TODO(MultilayerNetwork mnet, Layer layer)
{
// 3 x Number of triangles / number of connected triplets of vertices
// number of closed triplets / number of connected triplets of vertices
var triangleCount = 0;
double tripletsCount = 0;
var nodes = mnet.NodesByLayer[layer.Id];
// Count the triangles.
foreach (var v in nodes)
{
foreach (var u in nodes)
{
if (v == u || mnet.GetEdge(v, u) == null)
{
continue;
}
foreach (var w in nodes)
{
if (u == w || mnet.GetEdge(v, w) == null)
{
continue;
}
// Check for the final path.
if (mnet.GetEdge(u, w) != null)
{
triangleCount++;
}
}
}
}
var edgesCount = mnet.EdgesByLayerPair[layer.Id][layer.Id].Count;
return((3 * triangleCount) / tripletsCount);
}
/// <summary>
/// Flatten layers into single layer.
/// </summary>
/// <param name="mnet">Multilayer network.</param>
/// <param name="newLayerName">Name of the new layer.</param>
/// <param name="layers">Layers to flatten.</param>
/// <param name="forceDirected">True if new edges should be directed, false if not.</param>
/// <param name="forceActors">True if all actors should be on the new layer, false if not.</param>
/// <returns>Flattened layer.</returns>
public Layer FlattenUnweighted(MultilayerNetwork mnet, string newLayerName, HashSet <Layer> layers,
bool forceDirected = false, bool forceActors = false)
{
var newLayer = createLayer(mnet, newLayerName, layers, forceDirected, forceActors);
var directed = mnet.IsDirected(newLayer, newLayer);
foreach (var layer1 in layers)
{
foreach (var layer2 in layers)
{
foreach (var edge in mnet.GetEdges(layer1, layer2))
{
var node1 = mnet.GetNode(edge.V1.Actor, newLayer);
var node2 = mnet.GetNode(edge.V2.Actor, newLayer);
var newEdge = mnet.GetEdge(node1, node2);
if (newEdge == null)
{
newEdge = mnet.AddEdge(node1, node2);
}
// If new layer is directed, undirected edges must be added twice in both directions.
if (directed && edge.Directionality == EdgeDirectionality.Undirected)
{
newEdge = mnet.GetEdge(node2, node1);
if (newEdge == null)
{
newEdge = mnet.AddEdge(node2, node1);
}
}
}
}
}
return(newLayer);
}
