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// Math.NET Numerics, part of the Math.NET Project
// http://numerics.mathdotnet.com
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using System;
using MathNet.Numerics;
using MathNet.Numerics.Distributions;

namespace Examples.SignalsExamples
{
    /// <summary>
    /// Example of generic function sampling and quantization provider
    /// </summary>
    public class Random : IExample
    {
              /// <summary>
        /// Gets the name of this example
        /// </summary>
        public string Name
        {
            get
            {
                return "Sampling - Random";
            }
        }

        /// <summary>
        /// Gets the description of this example
        /// </summary>
        public string Description
        {
            get
            {
                return "Samples a function randomly with the provided distribution";
            }
        }

        /// <summary>
        /// Run example
        /// </summary>
        public void Run()
        {
            // 1. Get 10 random samples of f(x) = (x * x) / 2 using continuous uniform distribution on [-10, 10]
            var uniform = new ContinuousUniform(-10, 10);
            var result = Generate.RandomMap(10, uniform, Function);
            Console.WriteLine(@" 1. Get 10 random samples of f(x) = (x * x) / 2 using continuous uniform distribution on [-10, 10]");
            for (var i = 0; i < result.Length; i++)
            {
                Console.Write(result[i].ToString("N") + @" ");
            }

            Console.WriteLine();
            Console.WriteLine();

            // 2. Get 10 random samples of f(x) = (x * x) / 2 using Exponential(1) distribution and retrieve sample points
            var exponential = new Exponential(1);
            double[] samplePoints = Generate.Random(10, exponential);
            result = Generate.Map(samplePoints, Function);
            Console.WriteLine(@"2. Get 10 random samples of f(x) = (x * x) / 2 using Exponential(1) distribution and retrieve sample points");
            Console.Write(@"Points: ");
            for (var i = 0; i < samplePoints.Length; i++)
            {
                Console.Write(samplePoints[i].ToString("N") + @" ");
            }

            Console.WriteLine();
            Console.Write(@"Values: ");
            for (var i = 0; i < result.Length; i++)
            {
                Console.Write(result[i].ToString("N") + @" ");
            }

            Console.WriteLine();
            Console.WriteLine();

            // 3. Get 10 random samples of f(x, y) = (x * y) / 2 using ChiSquare(10) distribution
            var chiSquare = new ChiSquared(10);
            result = Generate.RandomMap2(10, chiSquare, TwoDomainFunction);
            Console.WriteLine(@" 3. Get 10 random samples of f(x, y) = (x * y) / 2 using ChiSquare(10) distribution");
            for (var i = 0; i < result.Length; i++)
            {
                Console.Write(result[i].ToString("N") + @" ");
            }

            Console.WriteLine();
        }

        /// <summary>
        /// Fucntion f(x, y) = (x * y) / 2
        /// </summary>
        /// <param name="x">Input value</param>
        /// <returns>Calculation result</returns>
        public double Function(double x)
        {
            return Math.Pow(x, 2) / 2;
        }

        /// <summary>
        /// Fucntion f(x,y) = (x * y) / 2
        /// </summary>
        /// <param name="x">X input value</param>
        /// <param name="y">Y input value</param>
        /// <returns>Calculation result</returns>
        public double TwoDomainFunction(double x, double y)
        {
            return (x * y) / 2;
        }
    }
}