网络编程（2）

08 并行

并行串行计算比较

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace test07
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private async void bt_Click(object sender, RoutedEventArgs e)
        {
            long[] t1 = await Task.Run(() => Multiply(200, 18, 27));
            tb.Text = string.Format("测试1（矩阵1：200x18，矩阵2：18x27），非并行用时{0}毫秒，并行用时{1}毫秒\n", t1[0], t1[1]);
            long[] t2 = await Task.Run(() => Multiply(2000, 180, 270));
            tb.Text += string.Format("测试1（矩阵1：2000x180，矩阵2：180x270），非并行用时{0}毫秒，并行用时{1}毫秒\n", t2[0], t2[1]);
            long[] t3 = await Task.Run(() => Multiply(2000, 200, 300));
            tb.Text += string.Format("测试1（矩阵1：2000x200，矩阵2：200x300），非并行用时{0}毫秒，并行用时{1}毫秒\n", t3[0], t3[1]);

        }

        /// <summary>
        /// 传入行数和列数，初始化一个矩阵
        /// </summary>
        /// <param name="rows"></param>
        /// <param name="cols"></param>
        /// <returns></returns>
        public static int[,] InitializeMatrix(int rows, int cols)
        {
            int[,] matrix = new int[rows, cols];
            Random r = new Random();
            for(int i = 0; i < rows; i++)
            {
                for(int j = 0; j < cols; j++)
                {
                    matrix[i, j] = r.Next(100);
                }
            }
            return matrix;
        }
        /// <summary>
        /// 普通方法计算矩阵乘法
        /// </summary>
        /// <param name="a"></param>
        /// <param name="b"></param>
        public static void CommonCompute(int[,] a,int[,] b)
        {
            int arows = a.GetLength(0);
            int acols = a.GetLength(1);
            int bcols = b.GetLength(1);
            int[,] result = new int[arows, bcols];
            for(int i = 0; i < arows; i++)
            {
                for(int j = 0; j < bcols; j++)
                {
                    int temp = 0;
                    for (int k = 0; k < acols; k++)
                    {
                        temp += a[i, k] * b[k, j];
                    }
                    result[i, j] = temp;
                }
            }
        }
        /// <summary>
        /// 并行方法计算矩阵乘法
        /// </summary>
        /// <param name="a"></param>
        /// <param name="b"></param>
        public static void ParallelCompute(int[,] a, int[,] b)
        {
            int arows = a.GetLength(0);
            int acols = a.GetLength(1);
            int bcols = b.GetLength(1);
            int[,] result = new int[arows, bcols];
            Action<int> action = i =>
            {
                for (int j = 0; j < bcols; j++)
                {
                    int temp = 0;
                    for (int k = 0; k < acols; k++)
                    {
                        temp += a[i, k] * b[k, j];
                    }
                    result[i, j] = temp;
                }
            };
            //外循环并行执行
            Parallel.For(0, arows, action);     
        }
        /// <summary>
        /// 计算矩阵乘法
        /// </summary>
        /// <param name="rows"></param>
        /// <param name="cols"></param>
        /// <param name="cols2"></param>
        /// <returns></returns>
        public static long[] Multiply(int rows,int cols,int cols2)
        {
            //初始化矩阵
            int[,] a = InitializeMatrix(rows, cols);
            int[,] b = InitializeMatrix(cols, cols2);

            Stopwatch watch = new Stopwatch();
            long[] timeElapsed = new long[2];
            //串行
            watch.Start();
            CommonCompute(a, b);
            watch.Stop();
            timeElapsed[0] = watch.ElapsedMilliseconds;
            //并行
            watch.Restart();
            ParallelCompute(a, b);
            watch.Stop();
            timeElapsed[1] = watch.ElapsedMilliseconds;
            return timeElapsed;
        }
    }
}