1.5.4.1. fejezet, Paralell.For és ForEach

namespace ParalellMatrix
{
    class Program
    {
        static public double[,] GenerateMatrix(int size)
        {
            double[,] matrix = new double[size, size];
            Random r = new Random();
            for (int i = 0; i < size; ++i)
            {
                for (int j = 0; j < size; ++j)
                {
                    matrix[i, j] = r.Next(1000, 100000);
                }
            }
            return matrix;
        }
        static void Main(string[] args)
        {
            int size = 1000;
            double[,] a = GenerateMatrix(size);
            double[,] b = GenerateMatrix(size);
            double[,] c = new double[size, size];
            Stopwatch sw = new Stopwatch();
            sw.Start();
            for (int i = 0; i < size; ++i)
            {
                for (int j = 0; j < size; ++j)
                {
                    double v = 0;
                    for (int k = 0; k < size; ++k)
                    {
                        v += a[i, k] * b[k, j];
                    }
                    c[i, j] = v;
                }
            }
            sw.Stop();
            Console.WriteLine("A ciklus által felhasznált idő: {0} ms", sw.ElapsedMilliseconds);
            c = new double[size, size];
            sw.Reset();
            sw.Start();
            Parallel.For(0, size, (i) => {
                for (int j = 0; j < size; ++j)
                {
                    double v = 0;
                    for (int k = 0; k < size; ++k)
                    {                        
                        v += a[i, k] * b[k, j];
                    }
                    c[i, j] = v;
                }
            });
            sw.Stop();
            Console.WriteLine("A ciklus által felhasznált idő: {0} ms", sw.ElapsedMilliseconds);
            Console.ReadKey();
        }
    }
}

            DirectoryInfo di = new DirectoryInfo("C:\\");
            Parallel.ForEach(di.GetFiles(), (file) => 
            {
                Console.WriteLine(file.FullName);
            });
            Console.ReadKey();