C# 我做的 "Bays & Durham Randomization by Shuffling"正确吗？

Question

我尝试使用“Bays & Durham Randomization by Shuffling”算法即兴创作一个随机数生成器。我按照在线教程制作了这段代码:

 public int[] GenerateRandomSequence_Improved(int n, int min, int max)
 {
       int[] seq = new int[n];
       for(int i = 0; i < n; i++)
       {
           int rand = GenerateNextRandomNumber(min, max);

           rand = min + rand % (max + 1 - min);
           seq[i] = rand;
       }
       return seq;
 }

我想知道我做的对不对..

编辑:这是 GenerateNextRandomNumber 方法的代码

public int GenerateNextRandomNumber(int min, int max)
{
       return cSharpRNG.Next(min,max);
}

Answer 1

根据 Knuth TAOCP Vol. 2 页34 算法B，正确的算法如下，

public class BaysDurham
{
    private readonly int[] t;
    private int y;      // auxiliary variable

    // Knuth TAOCP Vol. 2 p. 34 Algorithm B

    public BaysDurham(int k)
    {
        t = new int[k];

        for (int i = 0; i < k; i++)
        {
            t[i] = rand.Next();
        }

        y = rand.Next();
    }

    public int Next()
    {
        var i = (int)((t.Length * (long) y) / int.MaxValue);   // mitigates the bias
        y = t[i];
        t[i] = rand.Next();
        return y;
    }

    private readonly Random rand = new Random();
}

我让您调整输出范围，但只知道您使用模数的公式会引入显着偏差并使分布不均匀 please look at this .