///<summary>
/// Random graph generator for sparse graphs.
///</summary>
private void GenerateSparseGraph(IGraph G)
{
G.Clear();
IMapper <IPortOwner, int> index = new DictionaryMapper <IPortOwner, int>();
int n = NodeCount;
int m = Math.Min(GetMaxEdges(), EdgeCount);
INode[] V = new INode[n];
for (int i = 0; i < n; i++)
{
V[i] = G.CreateNode();
index[V[i]] = i;
}
RandomSupport.Permutate(random, V);
int count = m;
while (count > 0)
{
int vi = random.Next(n);
INode v = V[vi];
INode w = V[random.Next(n)];
if (G.GetEdge(v, w) != null || (v == w && (!AllowSelfLoops || !AllowCycles)))
{
continue;
}
G.CreateEdge(v, w);
count--;
}
if (!AllowCycles)
{
foreach (IEdge edge in G.Edges)
{
IPort sourcePort = edge.SourcePort;
IPort targetPort = edge.TargetPort;
if (index[sourcePort.Owner] > index[targetPort.Owner])
{
G.SetEdgePorts(edge, targetPort, sourcePort);
}
}
}
}
///<summary>
/// Random graph generator for dense graphs.
///</summary>
private void GenerateDenseGraph(IGraph g)
{
g.Clear();
INode[] nodes = new INode[NodeCount];
for (int i = 0; i < NodeCount; i++)
{
nodes[i] = g.CreateNode();
}
RandomSupport.Permutate(random, nodes);
int m = Math.Min(GetMaxEdges(), EdgeCount);
int n = NodeCount;
int adder = (AllowSelfLoops && AllowCycles) ? 0 : 1;
bool[] edgeWanted = RandomSupport.GetBoolArray(random, GetMaxEdges(), m);
for (int i = 0, k = 0; i < n; i++)
{
for (int j = i + adder; j < n; j++, k++)
{
if (edgeWanted[k])
{
if (AllowCycles && random.NextDouble() > 0.5f)
{
g.CreateEdge(nodes[j], nodes[i]);
}
else
{
g.CreateEdge(nodes[i], nodes[j]);
}
}
}
}
}
