← All NMath Code Examples

```using System;

using CenterSpace.NMath.Core;

namespace CenterSpace.NMath.Core.Examples.CSharp
{
/// <summary>
/// A .NET example in C# showing how to create a random number generator for a
/// particular probability distribution using a specified uniform deviate
/// method. Also shown is how to access and modify the uniform deviate
/// generating object from the NMath Core random number generator object.
/// </summary>
{

static void Main( string[] args )
{
Console.WriteLine();

// Create a RandomNumberGenerator.UniformRandomNumber delegate object
// from the method System.Random.NextDouble().
var sysRand = new Random();
var uniformDeviates = new RandomNumberGenerator.UniformRandomNumber( sysRand.NextDouble );

// Now, construct a binomial random number generator using this delegate to
// generate uniformly distributed random deviates between 0 and 1 (the
// binomial generator will transform these uniform deviates into binomial
// deviates).
int trials = 2000;
double prob = 0.002;
var binRand = new RandGenBinomial( trials, prob, uniformDeviates );

// Create a vector of binomial deviates and use it to create a histogram.
int n = 200;
var randomVec = new DoubleVector( n, binRand );

// Create histogram
int numBins = 20;
var h = new Histogram( numBins, randomVec );
Console.WriteLine( h.StemLeaf() );

// Change the uniform deviate generator to use the method NextDouble() form
// NMath Cores RandGenMTwist class.
int seed = 0x124;

// Construct the MT generator with the given seed.
var mt = new RandGenMTwist( seed );

// Create the delegate.
uniformDeviates = new RandomNumberGenerator.UniformRandomNumber( mt.NextDouble );

// Use the delegate to generate the uniform deviates necessary to for the
// binomial generator.
binRand.UniformDeviateMethod = uniformDeviates;

// Generate a vector of binomial deviates.
var randomSequence1 = new DoubleVector( n, binRand );

// All NMathCore random number generator classes have Reset() and Reset(int)
// methods that attempt to reset the underlying uniform generator with the
// time of day, for the no argument reset, or the given seed, for the integer
// argument version. These methods return true if the reset was successful and
// false if it was not. The reset methods will succeed if the following
// conditions are met:
// 1. The uniform generator delegate is an instance method, i.e. the Target
//    property of the Delegate class returns a non-null reference.
// 2. The object reference thus obtained has a method named Initialize that
//    returns void and takes no arguments, for the Reset() method, or a
//    single integer argument for the Reset(int) method.
// The RandGenMTwist class has an Initialize(int) method, so the Reset(int)
// method should succeed.
if ( binRand.Reset( seed ) )
{
// Random sequences started using the same seed, so they should be identical.
var randomSequence2 = new DoubleVector( n, binRand );
Console.WriteLine( "randomSequence1 == randomSequence2 is {0}", randomSequence1 == randomSequence2 );
}
else
{
Console.WriteLine( "Could not reset generator" );
}

Console.WriteLine();
Console.WriteLine( "Press Enter Key" );