Random Number Generators QuickStart Sample (C#)

Illustrates how to use specialized random number generator classes in the Extreme.Statistics.Random namespace in C#.

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using System;

using Extreme.Statistics.Random;
using Extreme.Mathematics.LinearAlgebra;

namespace Extreme.Numerics.QuickStart.CSharp
{
	/// <summary>
	/// Illustrates the use of the classes that implement
	/// pseudo-random number generators.
	/// </summary>
	class RandomNumberGenerators
	{
		/// <summary>
		/// The main entry point for the application.
		/// </summary>
		[STAThread]
		static void Main(string[] args)
		{
			// This QuickStart Sample gives an overview of the pseudo-random
			// number generators that provide an alternative for the
			// System.Random class..

			//
			// ExtendedRandom class
			//

			// The ExtendedRandom class simply extends the functionality
			// of the System.Random class:
			ExtendedRandom extended = new ExtendedRandom();
			int[] intValues = new int[100];
			double[] doubleValues = new double[100];

			// The fill method fills an array of integers with random numbers
			extended.Fill(intValues);
			Console.WriteLine("integer(99) = {0}", intValues[99]);

			// Or, it can generate uniform real values:
			extended.Fill(doubleValues);
			Console.WriteLine("double(99) = {0}", doubleValues[99]);

			// All random number generators can also produce variates 
			// from any user-specified probability distribution.
			// The NonUniformRandomNumbers sample illustrates 
			// how to do this.


			//
			// RANLUX Generators
			//

			// The RANLUX generators are available with three different 
			// 'luxury levels.' Each level produces random numbers of 
			// increasing quality at a performance cost.
			//
			// There are four constructors. The first constructor uses the
			// default seed and the default (lowest) luxury level:
			RanLux ranLux1 = new RanLux();

			// We can specify a seed value as well:
			RanLux ranLux2 = new RanLux(99);

			// We can specify the luxury level in the constructor:
			RanLux ranLux3 = new RanLux(RanLuxLuxuryLevel.Better);

			// Finally, we can specify both a seed and the luxury level:
			RanLux ranLux4 = new RanLux(99, RanLuxLuxuryLevel.Best);

			// All methods of System.Random and ExtendedRandom are available:
			ranLux1.Fill(intValues);
			ranLux2.Fill(doubleValues);
			Console.WriteLine("Integer from RanLux(Best): {0}", ranLux3.Next(100));


			//
			// Generalized Feedback Shift Register Generator
			//

			// This generator is implemented by the GfsrGenerator class.
			// It has three constructors. A default constructor that uses
			// a default seed value:
			GfsrGenerator gfsr1 = new GfsrGenerator();

			// A constructor that takes a single integer seed:
			GfsrGenerator gfsr2 = new GfsrGenerator(99);

			// And a constructor that takes an array of integers
			// as its seed. The maximum size of this seed array
			// is 2^14-1 = 16383.
			GfsrGenerator gfsr3 = new GfsrGenerator(new int[] {99, 17, int.MaxValue});

			// Once again, all standard methods are available.
			Console.WriteLine("Double from GFSR: {0}", gfsr2.NextDouble());

			//
			// Mersenne Twister
			//

			// The Mersenne Twister is a variation on the GFSR generator and,
			// not surprisingly, also has three constructors:
			MersenneTwister mersenne1 = new MersenneTwister();
			MersenneTwister mersenne2 = new MersenneTwister(99);
			MersenneTwister mersenne3 = new MersenneTwister(new int[] {99, 17, int.MaxValue});

			Console.Write("Press any key to exit.");
			Console.ReadLine();
		}
	}
}