using System;

using System.Linq;

using NWaves.Transforms;

using MathNet.Numerics.IntegralTransforms;

public class Program

{

    public static void Main()

    {

        // NWaves:

        var x = new float[] { 1, 5, 2, 8, 5, 23, 8, 1, 9, 9, 2, 12, 31, 0, 8, 17 };

        new HartleyTransform(16).Direct(x);

​

        // MathNet.Numerics

        var d = new double[] { 1, 5, 2, 8, 5, 23, 8, 1, 9, 9, 2, 12, 31, 0, 8, 17 };

        var dx = Hartley.NaiveForward(d, HartleyOptions.NoScaling);

        // Result:

        foreach (var el in x)

            Console.Write(el + " ");

        // Difference:

        Console.WriteLine();

        for (var i = 0; i < x.Length; i++)

            Console.Write(x[i] - dx[i] + " ");

    }

}