构建并行for循环

Question

这是到目前为止的全部代码。我只是无法让这一行运行。我需要“并行”线的帮助。这是针对需要多线程的矩阵乘法问题。程序运行直到输出然后它会爆炸。请帮忙！

using System;
using System.Collections.Generic;
using System.Collections.Concurrent;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace matrix_multiplication
{
    class Program
    {
        static void Main(string[] args)
        {
            int i, j,m,n; //This is where you tell the PC you want a number and store the var// 
            Console.WriteLine("Enter the number of rows (must be >1) you want in the MATRIX:"); //This writes to the screen//
            m = Convert.ToInt32(Console.ReadLine()); //This converts the input to a number//

            Console.WriteLine("Enter the number of columns (must be >1) you want in the MATRIX:");
            n = Convert.ToInt32(Console.ReadLine());

            int[,] a = new int[m, n];
            Console.WriteLine("Enter the numbers for the first MATRIX:");
            for (i = 0; i < m; i++)
            {
                for (j = 0; j < n; j++)
                {
                    a[i, j] = int.Parse(Console.ReadLine());
                }
            }

            Console.WriteLine("The first MATRIX is:");
            for (i = 0; i < m; i++)
            {
                for (j = 0; j < n; j++)
                {
                    Console.Write(a[i, j]+"\t");
                }
                Console.WriteLine();
            }

            int[,] b = new int[m, n];
            Console.WriteLine("Enter the numbers for the second MATRIX:");
            for (i = 0; i < m; i++)
            {
                for (j = 0; j < n; j++)
                {
                    b[i, j] = int.Parse(Console.ReadLine());
                }
            }
            Console.WriteLine("The second MATRIX is:");
            for (i = 0; i < 2; i++)
            {
                for (j = 0; j < 2; j++)
                {
                    Console.Write(b[i, j]+"\t");
                }
                Console.WriteLine();
            }

            Console.WriteLine("The MATRIX multiplication is:");
            int[,] c = new int[m, n];
           **Parallel.For(0, m,  =>**
            {
                for (j = 0; j < n; j++)
                {
                    c[i, j] = 0;
                    for (int k = 0; k < 2; k++)
                    {
                        c[i, j] += a[i, k] * b[k, j];
                    }
                }
            }); 



            for (i = 0; i < m; i++)
            {
                for (j = 0; j < n; j++)
                {
                    Console.Write(c[i, j]+"\t");
                }
                Console.WriteLine();
            }
            Console.ReadKey();
        }
    }
}

Answer 1

试试这个：

int m, n; //This is where you tell the PC you want a number and store the var// 
        Console.WriteLine("Enter the number of rows (must be >1) you want in the MATRIX:"); //This writes to the screen//
        m = Convert.ToInt32(Console.ReadLine()); //This converts the input to a number//

        Console.WriteLine("Enter the number of columns (must be >1) you want in the MATRIX:");
        n = Convert.ToInt32(Console.ReadLine());

        int[,] a = new int[m, n];
        Console.WriteLine("Enter the numbers for the first MATRIX:");
        for (int i = 0; i < m; i++)
        {
            for (int j = 0; j < n; j++)
            {
                a[i, j] = int.Parse(Console.ReadLine());
            }
        }

        Console.WriteLine("The first MATRIX is:");
        for (int i = 0; i < m; i++)
        {
            for (int j = 0; j < n; j++)
            {
                Console.Write(a[i, j] + "\t");
            }
            Console.WriteLine();
        }

        int[,] b = new int[m, n];
        Console.WriteLine("Enter the numbers for the second MATRIX:");
        for (int i = 0; i < m; i++)
        {
            for (int j = 0; j < n; j++)
            {
                b[i, j] = int.Parse(Console.ReadLine());
            }
        }
        Console.WriteLine("The second MATRIX is:");
        for (int i = 0; i < 2; i++)
        {
            for (int j = 0; j < 2; j++)
            {
                Console.Write(b[i, j] + "\t");
            }
            Console.WriteLine();
        }

        Console.WriteLine("The MATRIX multiplication is:");
        double[,] c = new double[m, n];

        // A basic matrix multiplication. 
        // Parallelize the outer loop to partition the source array by rows.
        Parallel.For(0, m, i =>
        {
            for (int j = 0; j < n; j++)
            {
                // Use a temporary to improve parallel performance. 
                double temp = 0;
                for (int k = 0; k < n; k++)
                {
                    temp += a[i, k] * b[k, j];
                }
                c[i, j] = temp;
            }
        }); // Parallel.For



        for (int i = 0; i < m; i++)
        {
            for (int j = 0; j < n; j++)
            {
                Console.Write(c[i, j] + "\t");
            }
            Console.WriteLine();
        }
        Console.ReadKey();

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