/// <summary>
/// Adds edgeCount number of edges to network. AllowMultiEdges and AllowSelfLoops will affect
/// how edges are added.
/// </summary>
public static void CreateEdges(INetworkAdjList network, int edgeCount)
{
Random rand = new Random(DateTime.Now.Millisecond);
int srcNodeIndex = -1;
int destNodeIndex = -1;
INode srcNode = null;
INode destNode = null;
for (int i = 0; i < edgeCount; i++)
{
srcNodeIndex = rand.Next(network.NodeCount);
destNodeIndex = rand.Next(network.NodeCount);
srcNode = network.Nodes[srcNodeIndex];
destNode = network.Nodes[destNodeIndex];
if (!AllowMultiEdges && AllowSelfLoops)
{
if (network.IsEdge(srcNode, destNode))
continue;
else
network.CreateEdge(srcNode, destNode);
}
else if (AllowMultiEdges && !AllowSelfLoops)
{
if (srcNode == destNode)
continue;
else
network.CreateEdge(srcNode, destNode);
}
else
network.CreateEdge(srcNode, destNode);
}
}
public void GarunteeEdgeCount(int edgeCount, INetworkAdjList network)
{
Random rand = new Random();
while (network.EdgeCount < edgeCount)
{
int index0 = rand.Next(network.EdgeCount);
int index1 = rand.Next(network.EdgeCount);
INode node0 = network.Nodes[index0];
INode node1 = network.Nodes[index1];
network.CreateEdge(node0, node1);
}
}
/// <summary>
/// Ensures a minimum number of self loops exist in the network.
/// </summary>
public static void EnsureMinSelfLoopCount(INetworkAdjList network, int n)
{
int ctr = 0;
foreach (IEdge edge in network.EdgeEnumerator)
{
if (edge.IsSelfLoop)
ctr++;
}
// if that many self loops exist, return
if (ctr>=n)
return;
// else create the needed number of self loops
int needed = n;
if (n<ctr)
needed = ctr-n;
ctr=0; // re-use ctr variable
do
{
foreach (INode node in network.NodeEnumerator)
{
network.CreateEdge(node, node);
ctr++;
if (ctr>=needed)
break;
}
} while (needed>ctr);
}