Потоки

using System;
using System.Threading;

namespace Lr
{
    class Program
    {
        static int sign(object z)
        {
            Console.WriteLine("\nsign виконується в потоці: " + Thread.CurrentThread.ManagedThreadId);

            if ((double)z > 0)
                return 1;
            else
                return -1;
        }

        static double sum(int k, double[,] d, double[,] s)
        {
            int i;
            double sum = 0;

            for (i = 0; i <= k - 2; i++)
                sum += d[i, i] * Math.Pow(s[i, k], 2);

            return sum;
        }

        static double sum(int k, int j, double[,] d, double[,] s)
        {
            double sum = 0;

            for (int i = 0; i <= k - 2; i++)
            {
                sum += d[i, i] * s[i, k] * s[i, j];
            }

            return sum;
        }

        static double sum(int i, double[,] d, double[] y, double[,] s)
        {
            double sum = 0;

            for (int k = 0; k <= i - 2; k++)
                sum += d[k, k] * y[k] * s[k, i];

            return sum;
        }

        static double sum(int i, double[,] s, double[] x)
        {
            double sum = 0;

            for (int k = i + 1; k <= 5 - 1; k++)
                sum += s[i, k] * x[k];
            Console.WriteLine("\nSum виконується в потоці: " + Thread.CurrentThread.ManagedThreadId);
            return sum;
        }
        static void Print(object a)
        {
            Console.WriteLine("\nPrint виконується в потоці: " + Thread.CurrentThread.ManagedThreadId);

            double[,] arr = (double[,])a;
            for (int i = 0; i < arr.GetLength(0); i++)
            {
                for (int j = 0; j < arr.GetLength(1); j++)
                {
                    Console.Write($"{arr[i, j]:f3}\t");
                }
                Console.WriteLine();
            }

        }

        static void ThreadWithParameters() => Console.WriteLine("\nПотік без параметрів: " + Thread.CurrentThread.ManagedThreadId);

        static void Starting()
        {
            const int n = 5;
            const int d = -5;
            const double q = -2.58;

            double[,] a = { { q, 1, 0, 0, 0 }, { 1, -2, 1, 0, 0 }, { 0, 1, -2, 1, 0 }, { 0, 0, 1, -2, 1 }, { 0, 0, 0, 1, q } };
            double[] b = { 0, d, d, d, 0 };
            double[,] s = { { 0, 0, 0, 0, 0 }, { 0, 0, 0, 0, 0 }, { 0, 0, 0, 0, 0 }, { 0, 0, 0, 0, 0 }, { 0, 0, 0, 0, 0 } };
            double[,] s_t = new double[n, n];
            double[,] dArr = { { 0, 0, 0, 0, 0 }, { 0, 0, 0, 0, 0 }, { 0, 0, 0, 0, 0 }, { 0, 0, 0, 0, 0 }, { 0, 0, 0, 0, 0 } };
            double[] x = new double[n];
            double[] y = new double[n];
            int i, j, k;

            dArr[0, 0] = sign(a[0, 0]);
            s[0, 0] = Math.Sqrt(Math.Abs(a[0, 0]));

            for (k = 0; k < n; k++)
            {
                if (k != 0)
                {
                    dArr[k, k] = sign(a[k, k] - sum(k, dArr, s));
                    s[k, k] = Math.Sqrt(Math.Abs(a[k, k] - sum(k, dArr, s)));
                    Console.WriteLine($"s[{k}, {k}] = {s[k, k]:f3}");
                }
                for (j = k + 1; j < n; j++)
                {
                    s[k, j] = (a[k, j] - sum(k, j, dArr, s)) / (s[k, k] * dArr[k, k]);
                    Console.WriteLine($"s[{k}, {j}] = {s[k, j]:f3}");
                }
            }
            Console.WriteLine();
            Console.WriteLine();

            Thread t1 = new Thread(Print);
            t1.Start(s);
           // Print(s);

            for (i = 0; i < n; i++)
            {
                for (j = 0; j < n; j++)
                {
                    s_t[i, j] = s[j, i];
                }
            }
            Console.WriteLine();
            Console.WriteLine();
            Console.WriteLine();

            Thread t2 = new Thread(Print);
            t2.Start(s_t);

            Console.WriteLine();

            y[0] = b[0] / (s[0, 0] * dArr[0, 0]);
            for (i = 0; i < n; i++)
                y[i] = (b[i] - sum(i, dArr, y, s)) / (s[i, i] * dArr[i, i]);
            for (i = 0; i < n; i++)
                Console.WriteLine("{0:f3}", y[i]);

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

            for (i = n - 1; i >= 0; i--) // n-1 ! n - выход за пределы массива
                x[i] = (y[i] - sum(i, s, x)) / s[i, i];
            for (i = 0; i < n; i++)
                Console.WriteLine("{0:f3}", x[i]);
        }
        static void Main(string[] args)
        {
            try
            {
                Console.WriteLine("\nГоловний потiк: " + Thread.CurrentThread.ManagedThreadId + "\n");
                Thread t1 = new Thread(ThreadWithParameters);
                t1.Start();
                Thread t2 = new Thread(Starting);
                t2.Start();

            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }

            Console.ReadKey();
        }

    }
}