/// <summary>
/// Returns a random simple bipartite graph on <c>V1</c> and <c>V2</c> vertices,
/// containing each possible edge with probability <c>p</c>.</summary>
/// <param name="V1">the number of vertices in one partition</param>
/// <param name="V2">the number of vertices in the other partition</param>
/// <param name="p">the probability that the graph contains an edge with one endpoint in either side</param>
/// <returns>a random simple bipartite graph on <c>V1</c> and <c>V2</c> vertices,
/// containing each possible edge with probability <c>p</c></returns>
/// <exception cref="ArgumentException">if probability is not between 0 and 1</exception>
///
public static Graph Bipartite(int V1, int V2, double p)
{
if (p < 0.0 || p > 1.0)
{
throw new ArgumentException("Probability must be between 0 and 1");
}
int[] vertices = new int[V1 + V2];
for (int i = 0; i < V1 + V2; i++)
{
vertices[i] = i;
}
StdRandom.Shuffle(vertices);
Graph G = new Graph(V1 + V2);
for (int i = 0; i < V1; i++)
{
for (int j = 0; j < V2; j++)
{
if (StdRandom.Bernoulli(p))
{
G.AddEdge(vertices[i], vertices[V1 + j]);
}
}
}
return(G);
}
public static void MainTest(string[] args)
{
int n = int.Parse(args[0]);
if (args.Length == 2)
{
StdRandom.Seed = int.Parse(args[1]);
}
double[] probabilities = { 0.5, 0.3, 0.1, 0.1 };
int[] frequencies = { 5, 3, 1, 1 };
string[] a = "A B C D E F G".Split(' ');
Console.WriteLine("seed = " + StdRandom.Seed);
for (int i = 0; i < n; i++)
{
Console.Write("{0} ", StdRandom.Uniform(100));
Console.Write("{0:F5} ", StdRandom.Uniform(10.0, 99.0));
Console.Write("{0} ", StdRandom.Bernoulli(0.5));
Console.Write("{0:F5} ", StdRandom.Gaussian(9.0, 0.2));
Console.Write("{0} ", StdRandom.Discrete(probabilities));
Console.Write("{0} ", StdRandom.Discrete(frequencies));
StdRandom.Shuffle(a);
foreach (string s in a)
{
Console.Write(s);
}
Console.WriteLine();
}
}
// tournament
/// <summary>
/// Returns a random tournament digraph on <c>V</c> vertices. A tournament digraph
/// is a DAG in which for every two vertices, there is one directed edge.
/// A tournament is an oriented complete graph.</summary>
/// <param name="V">the number of vertices</param>
/// <returns>a random tournament digraph on <c>V</c> vertices</returns>
///
public static Digraph Tournament(int V)
{
Digraph G = new Digraph(V);
for (int v = 0; v < G.V; v++)
{
for (int w = v + 1; w < G.V; w++)
{
if (StdRandom.Bernoulli(0.5))
{
G.AddEdge(v, w);
}
else
{
G.AddEdge(w, v);
}
}
}
return(G);
}
/// <summary>
/// Returns a random simple graph on <c>V</c> vertices, with an
/// edge between any two vertices with probability <c>p</c>. This is sometimes
/// referred to as the Erdos-Renyi random graph model.</summary>
/// <param name="V">the number of vertices</param>
/// <param name="p">the probability of choosing an edge</param>
/// <returns>a random simple graph on <c>V</c> vertices, with an edge between
/// any two vertices with probability <c>p</c></returns>
/// <exception cref="ArgumentException">if probability is not between 0 and 1</exception>
///
public static Graph Simple(int V, double p)
{
if (p < 0.0 || p > 1.0)
{
throw new ArgumentException("Probability must be between 0 and 1");
}
Graph G = new Graph(V);
for (int v = 0; v < V; v++)
{
for (int w = v + 1; w < V; w++)
{
if (StdRandom.Bernoulli(p))
{
G.AddEdge(v, w);
}
}
}
return(G);
}