zoukankan      html  css  js  c++  java
  • Biased Random Number Generator

    I am looking for a random number generator that is biased towards giving numbers "furthest away" from a set of already selected numbers. 
    For example, if my range is [1, 50] and I pass in a set of numbers such as (1, 20, 40),
    then I would want the generator to "prefer" producing numbers further away from 1, 20, and 40.
    Therefore, numbers such as 50 or 30 would be more likely to be drawn than 20 or 40.
    I suspect that this may already exist. Does anyone know of such an implementation that I can use for Java?

    Here is a way you can do it by hand. Basically the idea is we take in some numbers we don't want to generate, then we generate a random number and if that number is in the list of numbers we don't want we try again up to a maximum number of retries.

    public static void main(String[] args) {
    
            int times = 25;
            int[] listOfNumbers = {1, 2, 3};
            int max = 5, min = 1;
    
            while(times-- > 0)
            {   
                System.out.print(GeneratePreferredNumbers(listOfNumbers, max, min) + " ");
            }
    
    
        }//main method
    
        public static Integer GeneratePreferredNumbers(int[] listOfNotPreffered, int max, int min)
        {
            Random rand = new Random();
            int randomNum;
            int retry = 1; //increasing this lessons the likely of our non-preferred numbers to show up
            HashSet<Integer> notPrefer = new HashSet<>();
    
            //add all the numbers we don't want to generate into a HashSet for easy lookup
            for(int index = 0; index < listOfNotPreffered.length; index++)
                notPrefer.add(listOfNotPreffered[index]);
    
            do {
                randomNum = rand.nextInt((max - min) + 1) + min;
                if(notPrefer.contains(randomNum))
                {
                    retry--;
                }
                //we found a good value, let's return it
                else{
                    retry = 0;
                }
            } while (retry > 0);
    
            return randomNum;
        }
    

      NOTE: The more times we allow the algorithm to retry the more likely our output will consist of numbers we want. This allows you to control how likely you want those non-preferred numbers to show up. This makes sense because if we were to increase the retry to infinite, this would stop only when the number generated is not contained in our list non-preferred numbers.

  • 相关阅读:
    [经验] 如何在虚拟机上安装 CentOS
    [经验] Java 使用 netty 框架, 向 Unity 客户端的 C# 实现通信[2]
    [经验] Java 使用 netty 框架, 向 Unity 客户端的 C# 实现通信 [1]
    [经验] 关于 Java 中的非空判断
    [经验] Java Web 项目怎么部署到 Linux 系统上
    求和
    引用与指针
    C++学习前言
    大O
    ubuntu连接不上mysql问题
  • 原文地址:https://www.cnblogs.com/apanda009/p/7953008.html
Copyright © 2011-2022 走看看