ПарПрог C# 2

using System;
using System.Dynamic;
using System.Threading;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    class Program
    {
        static double fun(double x)
        {
            double ans = 0;

            for (int k = 1; k <= Math.Max(20, (int)20 * Math.Abs(x)); ++k)
                for (int j = 1; j <= Math.Max(20, (int)20 * Math.Abs(x)); ++j)
                {
                    double x_2 = x * x;

                    ans += x_2 * (k + j) / (x_2 + k * k * k + j * j * j) * Math.Cos(k * x) * Math.Sin(j * x);
                }

            return ans;
        }

        static void Main()
        {
            const int N = 200;

            double[] X = new double[N + 1];

            for (int k = 0; k <= N; k++)
            {
                X[k] = 100 * Math.Cos(1.0 * k);
            }

            double S = 0;

            Int64 Tms = (DateTime.Now).Ticks;

            foreach (double x in X) S += fun(x);

            Tms = (DateTime.Now).Ticks - Tms;
            TimeSpan Tmss1 = new TimeSpan(Tms);

            Console.WriteLine("S=" + S.ToString());
            Console.WriteLine("Время выполнения последовательной операции foreach "+(Tmss1.TotalSeconds).ToString()+" c");

            Object obj = new Object();

            S = 0;
            Tms = (DateTime.Now).Ticks;

            Parallel.ForEach(X, x => {
                double Tmp = fun(x);
                lock (obj) { S += Tmp; }});

            Tms = (DateTime.Now).Ticks - Tms;
            TimeSpan Tmss2 = new TimeSpan(Tms);

            Console.WriteLine("S=" + S.ToString());
            Console.WriteLine("Время выполнения параллельного метода ForEach " + (Tmss2.TotalSeconds).ToString() + " c");

            double a = Tmss1 / Tmss2;

            Console.WriteLine("Ускорение: " + a);
        }
    };
}