具有TPL的多线程-访问内部类属性

Question

我正在使用TPL库来并行化2D网格操作。我从实际代码中提取了一个简单的示例来说明我在做什么。我得到了想要的结果，并且我的笔记本计算机（12）上的处理器数量加快了计算时间。

我很乐意就我的属性如何声明获得一些建议或意见。同样，它可以按预期工作，但是想知道设计是否会更好。先感谢您。

我的简化代码：

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace Gridding
{


    public abstract class Base
    {
        /// <summary>
        /// Values representing the mesh values where each node in the gridis assigned som value. 
        /// </summary>
        public float[,] Values { get; set; }
        public abstract void Compute();
    }


    public class Derived : Base
    {

        /// <summary>
        /// Make the mesh readonly.  Is this necessary?
        /// </summary>
        readonly Mesh MyMesh;

        Derived(Mesh mesh)
        {
            MyMesh = mesh;
        }


        public override void Compute()
        {
            Values = new float[MyMesh.NX, MyMesh.NY];

            double[] xn = MyMesh.GetXNodes();
            double[] yn = MyMesh.GetYNodes();

            /// Paralellize the threads along the columns of the grid using the Task Paralllel Library (TPL).
            Parallel.For(0, MyMesh.NX, i =>
            {
                Run(i, xn, yn);
            });
        }


        private void Run(int i, double[] xn, double[] yn)
        {
            /// Some long operation that parallelizes along the columns of a mesh/grid
            double x = xn[i];
            for (int j = 0; j < MyMesh.NY; j++)
            {

                /// Again, longer operation here
                double y = yn[j];

                double someValue = Math.Sqrt(x * y); 
                Values[i, j] = (float)someValue;
            }
        }


        static void Main(string[] args)
        {
            int nx = 100;
            int ny = 120;
            double x0 = 0.0;
            double y0 = 0.0;
            double width = 100;
            double height = 120;

            Mesh mesh = new Mesh(nx, ny, x0, y0, width, height);

            Base tplTest = new Derived(mesh);
            tplTest.Compute();

            float[,] values = tplTest.Values;

            Console.Read();


        }

        /// <summary>
        /// A simple North-South oriented grid.
        /// </summary>
        class Mesh
        {
            public int NX { get; } = 100;
            public int NY { get; set; } = 150;
            public double XOrigin { get; set; } = 0.0;
            public double YOrigin { get; set; } = 0.0;
            public double Width { get; set; } = 100.0;
            public double Height { get; set; } = 150.0;
            public double DX { get; }
            public double DY { get; }

            public Mesh(int nx, int ny, double xOrigin, double yOrigin, double width, double height)
            {
                NX = nx;
                NY = ny;
                XOrigin = xOrigin;
                YOrigin = yOrigin;
                Width = width;
                Height = height;
                DX = Width / (NX - 1);
                DY = Height / (NY - 1);
            }

            public double[] GetYNodes()
            {
                double[] yNodeLocs = new double[NY];
                for (int i = 0; i < NY; i++)
                {
                    yNodeLocs[i] = YOrigin + i * DY;
                }
                return yNodeLocs;
            }

            public double[] GetXNodes()
            {
                double[] xNodeLocs = new double[NX];
                for (int i = 0; i < NX; i++)
                {
                    xNodeLocs[i] = XOrigin + i * DX;
                }
                return xNodeLocs;
            }
        }
    }
}

Answer 1

仅使用100到150个数组元素，并行设置开销会抵消增益。当修改XOrigin，NX，YOrigin或NY时，可以缓存GetXNodes()和GetYNodes()的结果并使所缓存的值无效。