c# - 优化double for循环以提高执行速度

Question

我是 C# 的新手，我需要一些帮助来优化我的代码。

struct Data
{
    public static int numberOfPixels;
    public static string[] filePaths;
    public static string[] fileNames;
    public static double[] z;
    public static int numberOfFrames;
    public static byte[][] imageBuffer;
    public static int bufferSize = 1000;
    public static double[] num;
    public static double[] den;
}
public class Methods
{
    public void RetrieveFileList()
    {
        Console.WriteLine("Please enter the folder path where all measurement files are stored: ");
        Data.filePaths = Directory.GetFiles(Console.ReadLine(),"*.bin");
        Data.fileNames = new string[Data.filePaths.Length];
        Data.numberOfFrames = Data.filePaths.Length;
        Data.z = new double[Data.filePaths.Length];
        int n = 0;
        foreach(string file in Data.filePaths)
        {
            Data.fileNames[n] = Path.GetFileNameWithoutExtension(file);
            n++;
        }
    }
    public void CreatePositionArray()
    {
        Console.WriteLine("Please enter the stepsize used during the scan in nanometers: ");
        double stepsize = Convert.ToDouble(Console.ReadLine());
        int n = 0;
        foreach(string file in Data.fileNames)
        {
            Data.z[n] = Convert.ToInt32(file) * stepsize / 1000; 
            n++;
        }
    }
    public void InitializeBufferArray()
    {
        Data.imageBuffer = new byte[Data.numberOfFrames][];
    }
    public byte[] ReadBinaryFile(int index)
    {
        return File.ReadAllBytes(Data.filePaths[index]); ;
    }
    public void FillImageBuffer()
    {
        for (int i = 0; i < Data.bufferSize; i++)
        {
            Data.imageBuffer[i] = ReadBinaryFile(i);
        }
        Data.numberOfPixels = Data.imageBuffer[0].Length;
        Data.num = new double[Data.numberOfPixels];
        Data.den = new double[Data.numberOfPixels];
    }
}
class Program
{
    static void Main(string[] args)
    {
        Method.RetrieveFileList();
        Method.CreatePositionArray();
        Method.InitializeBufferArray();
        Method.FillImageBuffer();
        for(int i = 0; i < Data.numberOfFrames; i++)
        {
            for (int j = 0; j < Data.numberOfPixels; j++)
            {
                double der = Math.Pow(Data.imageBuffer[i+1][j] - Data.imageBuffer[i][j], 2);
                if (der < 1) der = 0;
                Data.num[j] = Data.num[j] + Data.z[i] * der;
                Data.den[j] = Data.den[j] + der;
            }
        } 
    }
}

特别是我的 Main 方法中的两个循环。现在这个循环处理大约 1000 帧，每帧 1210000 像素。外层循环的一次迭代执行大约需要 80 毫秒。 到这里最好的方法是什么？ 创建多个线程并将我的缓冲区拆分为预定义的垃圾或使用 Parallel 类？ 我将不胜感激任何形式的帮助。

谢谢。

Answer 1

您可能需要反转循环顺序以减少数组索引引用。此外，最好不要使用 Math.Pow(der, 2)，而是使用 der*der - 它会更快一些

     Method.RetrieveFileList();
     Method.CreatePositionArray();
     Method.InitializeBufferArray();
     Method.FillImageBuffer();
      for (int j = 0; j < Data.numberOfPixels; j++)  {
        double num = 0
        double den = 0;
        for(int i = 0; i < Data.numberOfFrames; i++) {
           double der = Data.imageBuffer[i+1][j] - Data.imageBuffer[i][j]     
           if ((der *= der) < 1) der = 0;
           num += Data.z[i] * der;
           den += der;
        }
        Data.num[j] = num;
        Data.den[j] = den;
   } 

老实说，我认为它不会显着提高性能。